Digital BW, The Print

This may border on OT, but here goes...

I'm looking for suggestions on testing a digital camera's BW mode against 
its color mode for BW output.  The question is: how does shooting in BW 
mode compare to shooting in color & converting later?  Converting later has 
the advantage of applying contrast filters after the fact.  Would BW mode 
be likely to offer advantages in, say, sharpness or dynamic range?  How 
would one test that?  In particular, what sort of test target would be best 
for sharpness?  Maybe something with saturated reds, greens & blues 
bordering each other to look for fringing.

The camera in question is a Canon G2.  It locks some functions in 'auto' 
for BW mode -- e.g., exposure is program mode only.  At least the ISO 
setting hold when switching to BW.  Low compression .jpg is the top quality 
save option in BW where Color includes a RAW ccd output losslessly 
compressed (about 2x the BW .jpg size).

Regards,
Bob G

Hi,  It seems the consensus on the digital photo boards is that 
capturing in full color on a digital camera is the way to go.  One of 
the main reasons is that many people use photoshop and it has a tool 
called "color mixer" which gives great flexibility in converting to 
bw.  You get to choose the percentage of each RGB channel you want in 
your BW image.  This means that it is easier emulate the different BW 
films (or just have more room for creativity).  Once I found it I 
havent gone back to the old "convert to momochrome" tool in photoshop.

Mark
BW pinhole and zone plate images -http://www.interwalk.com/gallery.htm


--- In DigitalBlackandWhiteThePrint@y..., bob geoghegan <bobgeo@d...> 
wrote:
> This may border on OT, but here goes...
> 
> I'm looking for suggestions on testing a digital camera's BW mode 
against 
> its color mode for BW output.  The question is: how does shooting 
in BW 
> mode compare to shooting in color & converting later?  Converting 
later has 
> the advantage of applying contrast filters after the fact.  Would 
BW mode 
> be likely to offer advantages in, say, sharpness or dynamic range?  
How 
> would one test that?  In particular, what sort of test target would 
be best 
> for sharpness?  Maybe something with saturated reds, greens & blues 
> bordering each other to look for fringing.
> 
> The camera in question is a Canon G2.  It locks some functions 
in 'auto' 
> for BW mode -- e.g., exposure is program mode only.  At least the 
ISO 
> setting hold when switching to BW.  Low compression .jpg is the top 
quality 

> save option in BW where Color includes a RAW ccd output losslessly 
> compressed (about 2x the BW .jpg size).
> 
> Regards,
> Bob G

It's called "channel mixer" ... not color mixer

snip
> the main reasons is that many people use photoshop and it has a tool
> called "color mixer" which gives great flexibility in converting to
> bw.  You get to choose the percentage of each RGB channel you want in
> your BW image.  This means that it is easier emulate the different BW

> films (or just have more room for creativity).  Once I found it I
> havent gone back to the old "convert to momochrome" tool in photoshop.

and "convert to profile" or grayscale mode conversion...

best,
Carolyn

--- ALONG THESE SAME LINES you can go to the WINDOW-SHOW channels. 
you will get the rgb image and the red, green and blue channels. this 
gives you an idea of what the image would look like with these three 
filters (don't ask me what specific filter numbers they are ). the 
red and the green are usually the most interesting. from there you 
can go to channel mixer and adjust the monochrome image. larry pirrone

 DigitalBlackandWhiteThePrint@y..., Carolyn  Frayn <carolyn@u...> 
wrote:
> It's called "channel mixer" ... not color mixer
> 
> snip
> > the main reasons is that many people use photoshop and it has a 
tool
> > called "color mixer" which gives great flexibility in converting 
to
> > bw.  You get to choose the percentage of each RGB channel you 
want in
> > your BW image.  This means that it is easier emulate the 
different BW
> 
> > films (or just have more room for creativity).  Once I found it I
> > havent gone back to the old "convert to momochrome" tool in 
photoshop.

> 
> and "convert to profile" or grayscale mode conversion...
> 
> best,
> Carolyn

I appreciate the suggestions on converting color to BW.  The benefits of 
post-shooting conversion from color are obvious.  But the other side of the 
question is if there are ever advantages in quality to using BW mode 
instead.  I'm wondering what sort of advantages those would be, if they 
even exist (I've only had the camera a week) .  Finer detail is a guess -- 
in limited tests I haven't seen this in BW mode but wondered what sort of 
subject would provide the best test.  Are there any other tests for quality 
that in theory might show better results in BW mode with a particular camera.

Bob G

At 01:23 PM 2/6/2002, you wrote:

>--- ALONG THESE SAME LINES you can go to the WINDOW-SHOW channels.
>you will get the rgb image and the red, green and blue channels. this
>gives you an idea of what the image would look like with these three
>filters (don't ask me what specific filter numbers they are ). the
>red and the green are usually the most interesting. from there you
>can go to channel mixer and adjust the monochrome image. larry pirrone
>
>  DigitalBlackandWhiteThePrint@y..., Carolyn  Frayn <carolyn@u...>
>wrote:
> > It's called "channel mixer" ... not color mixer
> >
> > snip
> > > the main reasons is that many people use photoshop and it has a
>tool
> > > called "color mixer" which gives great flexibility in converting
>to
> > > bw.  You get to choose the percentage of each RGB channel you
>want in
> > > your BW image.  This means that it is easier emulate the
>different BW
> >
> > > films (or just have more room for creativity).  Once I found it I
> > > havent gone back to the old "convert to momochrome" tool in
>photoshop.
> >
> > and "convert to profile" or grayscale mode conversion...
> >
> > best,
> > Carolyn
>
>
>
>Please visit the Group Homepage to check the Files, Bookmarks, Polls and 
>other resources as they are often being updated. The page is at:
>
>http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint
>
>Please follow these basic guidelines:
>- Include your full name with your message.
>- Include the address of your website, if you have one.
>- As threads develop, trim off excess portions of earlier messages to keep 
>them short.
>- As the topic of a thread changes remember to change the subject header.
>- Good manners are required at all time. No personal attacks or "flames."
>- Complete your Yahoo profile.
>- Before posting a question, search the message archives and the various 
>resources on the homepage.
>
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

--- I'M NO EXPERT here but it seems that you shoot in color you start 
with a larger file size and more bit depth (whatever the hell that 
means)so you have more information in the original file. is that any 
advantage? i don't know. would capture in color give you a greater 
tonal range? maybe. i guess i would shoot some finely detailed 
colored text  with both color and black and white modes and then loop 
the prints. i guess i never worried about it since i shoot large 
format (4x5) black and white and scan the negs.  larry

 DigitalBlackandWhiteThePrint@y..., bob geoghegan <bobgeo@d...> wrote:
> I appreciate the suggestions on converting color to BW.  The 
benefits of 
> post-shooting conversion from color are obvious.  But the other 
side of the 
> question is if there are ever advantages in quality to using BW 
mode 
> instead.  I'm wondering what sort of advantages those would be, if 
they 
> even exist (I've only had the camera a week) .  Finer detail is a 
guess -- 
> in limited tests I haven't seen this in BW mode but wondered what 
sort of 
> subject would provide the best test.  Are there any other tests for 
quality 
> that in theory might show better results in BW mode with a 
particular camera.
> 
> Bob G
> 
> At 01:23 PM 2/6/2002, you wrote:
> >--- ALONG THESE SAME LINES you can go to the WINDOW-SHOW channels.
> >you will get the rgb image and the red, green and blue channels. 
this
> >gives you an idea of what the image would look like with these 
three
> >filters (don't ask me what specific filter numbers they are ). the
> >red and the green are usually the most interesting. from there you
> >can go to channel mixer and adjust the monochrome image. larry 
pirrone
> >
> >  DigitalBlackandWhiteThePrint@y..., Carolyn  Frayn <carolyn@u...>
> >wrote:
> > > It's called "channel mixer" ... not color mixer
> > >
> > > snip
> > > > the main reasons is that many people use photoshop and it has 
a
> >tool
> > > > called "color mixer" which gives great flexibility in 
converting
> >to
> > > > bw.  You get to choose the percentage of each RGB channel you
> >want in
> > > > your BW image.  This means that it is easier emulate the
> >different BW
> > >
> > > > films (or just have more room for creativity).  Once I found 
it I
> > > > havent gone back to the old "convert to momochrome" tool in
> >photoshop.
> > >
> > > and "convert to profile" or grayscale mode conversion...
> > >
> > > best,
> > > Carolyn
> >
> >
> >
> >Please visit the Group Homepage to check the Files, Bookmarks, 
Polls and 
> >other resources as they are often being updated. The page is at:
> >
> >http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint
> >
> >Please follow these basic guidelines:
> >- Include your full name with your message.
> >- Include the address of your website, if you have one.
> >- As threads develop, trim off excess portions of earlier messages 
to keep 
> >them short.
> >- As the topic of a thread changes remember to change the subject 
header.
> >- Good manners are required at all time. No personal attacks 
or "flames."
> >- Complete your Yahoo profile.
> >- Before posting a question, search the message archives and the 
various 
> >resources on the homepage.
> >
> >
> >
> >
> >Your use of Yahoo! Groups is subject to 
http://docs.yahoo.com/info/terms/

Oops, yes thanks.  The risks of answering before coffee.

Mark
http://www.interwalk.com/gallery.htm

--- In DigitalBlackandWhiteThePrint@y..., Carolyn  Frayn 
<carolyn@u...> wrote:
> It's called "channel mixer" ... not color mixer
> 
> snip
> > the main reasons is that many people use photoshop and it has a 
tool
> > called "color mixer" which gives great flexibility in converting 
to
> > bw.  You get to choose the percentage of each RGB channel you 
want in
> > your BW image.  This means that it is easier emulate the 
different BW
> 
> > films (or just have more room for creativity).  Once I found it I
> > havent gone back to the old "convert to momochrome" tool in 
photoshop.

> 
> and "convert to profile" or grayscale mode conversion...
> 
> best,
> Carolyn

bob geoghegan wrote:

>  I appreciate the suggestions on converting color to BW.  The benefits of
> post-shooting conversion from color are obvious.  But the other side of the
> question is if there are ever advantages in quality to using BW mode
> instead.  I'm wondering what sort of advantages those would be, if they
> even exist (I've only had the camera a week) .  Finer detail is a guess --
> in limited tests I haven't seen this in BW mode but wondered what sort of
> subject would provide the best test.  Are there any other tests for quality
> that in theory might show better results in BW mode with a particular camera.
>
> Bob G
>

Conceptually shooting in B&W mode should give less interpolation, but it will
depend on how your particular camera captures the B&W data.

If you camera actually collects b&w data from each sensor, yes there would be
more detail.  But if, as I suspect, the camera still captures in color (R,G,G,B)
and then converts (on the fly) to B&W, you gain nothing.

When these digicams 'capture' all those claimed pixels, they don't really.  As I
have said several times before, these cameras concoct ('interpolate') a pixel's
worth of data from a third of a pixel's worth of information.  e.g.  A red
sensor produces, via interpolation an RGB pixel.

So....the best way to test the camera would be to use a highly detailed scene,
with very few straight lines.  These cameras do a very good job of
'interpolating' (another way of saying inventing) straight lines or images with
hard edges and broad areas of tone.

Highly detail scene therefore would be the most telling test.

Harvey Ferdschneider
partner, SKID Photography, NYC



[Non-text portions of this message have been removed]

> When these digicams 'capture' all those claimed pixels, they don't really.  As
> I
> have said several times before, these cameras concoct ('interpolate') a
> pixel's
> worth of data from a third of a pixel's worth of information.  e.g.  A red
> sensor produces, via interpolation an RGB pixel.
> 
> So....the best way to test the camera would be to use a highly detailed scene,
> with very few straight lines.  These cameras do a very good job of
> 'interpolating' (another way of saying inventing) straight lines or images
> with
> hard edges and broad areas of tone.

What I took from my question to Austin (Horses Mouth, about a week ago) is
that these one shot cameras interpolate color, not detail.

As you say "A red sensor produces, via interpolation an RGB pixel." That is
true for color mode, but as far as detail is concerned it doesn't care if
it's captured by an R, G, or B, sensor, and it only takes one color of
information to make detail. The depth of tone of that pixel may be differ
depending on which sensor records it, but a true pixel worth of detail
(let's call it a gray pixel) will be recorded.

Thus, for grayscale, the number of sensors the camera has IS the amount of
detail it records (raw) - no interpolation is necessary.

Todd

> What I took from my question to Austin (Horses Mouth, about a week ago) is
> that these one shot cameras interpolate color, not detail.

Yes and no...

> As you say "A red sensor produces, via interpolation an RGB
> pixel." That is
> true for color mode, but as far as detail is concerned it doesn't care if
> it's captured by an R, G, or B, sensor, and it only takes one color of
> information to make detail. The depth of tone of that pixel may be differ
> depending on which sensor records it, but a true pixel worth of detail
> (let's call it a gray pixel) will be recorded.

Well, yes and no...each sensor definitely gets unique data, but as far as it
being actual "grayscale" data, not really.  It's just like putting a
red/green/blue filter over your film camera, it may or may not "see" things.

> Thus, for grayscale, the number of sensors the camera has IS the amount of
> detail it records (raw) - no interpolation is necessary.

Well....not really...it still has to interpolate the "average" intensity
across colored sensors...

Austin

Todd Flashner wrote:

>
> > When these digicams 'capture' all those claimed pixels, they don't really.
> As
> > I
> > have said several times before, these cameras concoct ('interpolate') a
> > pixel's
> > worth of data from a third of a pixel's worth of information.  e.g.  A red
> > sensor produces, via interpolation an RGB pixel.
> >
> > So....the best way to test the camera would be to use a highly detailed
> scene,
> > with very few straight lines.  These cameras do a very good job of
> > 'interpolating' (another way of saying inventing) straight lines or images
> > with
> > hard edges and broad areas of tone.
>
> What I took from my question to Austin (Horses Mouth, about a week ago) is
> that these one shot cameras interpolate color, not detail.

I do not understand how one can separate 'color' information and 'detail'?  They
are one and the same.  It's not like there are separate or different parts that
make up the image.  A crude example of what it's *not* like would be the silver
matrix on which Kodachrome applies its dyes.

Harvey Ferdschneider
partner, SKID Photography, NYC


[Non-text portions of this message have been removed]

Hi Austin, thanks for weighing in.

>> As you say "A red sensor produces, via interpolation an RGB
>> pixel." That is
>> true for color mode, but as far as detail is concerned it doesn't care if
>> it's captured by an R, G, or B, sensor, and it only takes one color of
>> information to make detail. The depth of tone of that pixel may be differ
>> depending on which sensor records it, but a true pixel worth of detail
>> (let's call it a gray pixel) will be recorded.
> 
> Well, yes and no...each sensor definitely gets unique data, but as far as it
> being actual "grayscale" data, not really.  It's just like putting a
> red/green/blue filter over your film camera, it may or may not "see" things.

Well, to quote you, yes and no. Even the absence of light gets recorded as a
detail. It'd be a black pixel, no? As you say, if film is capable of so many
grains of info per unit measure of area, even empty areas represent
information.

What I mean is, if you use a high resolution film (like Techpan) to shoot a
piece of coal on snow, such that your image is composed of expanses of pure
black and pure white, you may have few tones, but the film still recorded
those two tones at great resolution.

>> Thus, for grayscale, the number of sensors the camera has IS the amount of
>> detail it records (raw) - no interpolation is necessary.
> 
> Well....not really...it still has to interpolate the "average" intensity
> across colored sensors...

This I don't get. Could you define that process a bit more for me. Why does
it have to average anything in grayscale?

Todd

> This I don't get. Could you define that process a bit more for
> me. Why does
> it have to average anything in grayscale?

More than likely, it takes the color value and just converts it to
grayscale.  I doubt they get more sophisticated than that, though they
could...somewhat.  You could possibly separate chrominance from luminance,
and somehow work with the data in that space, and get better actual
grayscale "data"...but I haven't do any work in that....yet.

Austin

on 2/7/02 12:53 AM, SKID Photography wrote:

>> What I took from my question to Austin (Horses Mouth, about a week ago) is
>> that these one shot cameras interpolate color, not detail.
>> 
> I do not understand how one can separate 'color' information and 'detail'?
> They are one and the same.  It's not like there are separate or different
> parts that make up the image.

Say your sensor is a grid of two sensors across by two down. In grayscale
mode you get a 4 pixel capture. You have 4 pixels of detail, represented by
one channel which has 4 pixels.

If the camera then applies an algorithm to give each of those pixels an RGB
component, that requires interpolation, and you'll end up 3 channels at 4
pixels each. You've added color channels, through interpolation, which may
or may not contain an accurate representation of the color they are tying to
create, but you've added no detail.

Nor have you lost any, but depending on how you convert that interpolated
color info back into grayscale, your file may stay as sharp as the original
4 pixel capture, or may get softer as you apply interpolated detail to your
original detail. However, the consequence of this softening could show up in
tonal smoothness. 

People will ague over which is better, but it often comes down to their
preference for one or the other between sharpness or tonal smoothness.

Todd

But in a typical digital camera there's a color filter placed over the chip
such that your 4 pixel grid would be:

[R][G]
[G][B]

...so there's no way to take a pure grayscale image, because there's a color
filter stuck on the chip. The camera can't not interpolate in greyscale
mode, because the only data it's capable of capturing is alread filtered for
color. See: http://www.foveon.com/interp.html

-Jason

> -----Original Message-----
> From: Todd Flashner [mailto:tflash@...]
> Sent: Thursday, February 07, 2002 1:23 AM
> To: DigitalBlackandWhiteThePrint@yahoogroups.com
> Subject: Re: [Digital BW] Re: Digicam in BW mode, how to test
>
> Say your sensor is a grid of two sensors across by two down. In grayscale
> mode you get a 4 pixel capture. You have 4 pixels of detail,
> represented by
> one channel which has 4 pixels.
>
> If the camera then applies an algorithm to give each of those
> pixels an RGB
> component, that requires interpolation, and you'll end up 3 channels at 4
> pixels each. You've added color channels, through interpolation, which may
> or may not contain an accurate representation of the color they
> are tying to
> create, but you've added no detail.

on 2/7/02 1:22 AM, Todd Flashner wrote:

Allow me to try to clarify something I wrote below, because as is it's
contradictory.

> If the camera then applies an algorithm to give each of those pixels an RGB
> component, that requires interpolation, and you'll end up 3 channels at 4
> pixels each. You've added color channels, through interpolation, which may
> or may not contain an accurate representation of the color they are tying to
> create, but you've added no detail.

Above I say that interpolation adds no detail.

Then below I say you may be able to take smoothness from the added detail.

I think I'm wrong about the below part. I was thinking of the three color
channels of scanned color film, where the channels don't always overlap each
other exactly, due to camera lens aberration, dye cloud composition, sensor
sensitivities, etc. But in the case of interpolated color I'd imagine the
registration between channels would be exact. You wouldn't gain tonal
smoothness, though you would still gain control over contrast and
"tonality".

But, nor would you loose detail from interpolation.

> Nor have you lost any, but depending on how you convert that interpolated
> color info back into grayscale, your file may stay as sharp as the original
> 4 pixel capture, or may get softer as you apply interpolated detail to your
> original detail. However, the consequence of this softening could show up in
> tonal smoothness.

My point in all this is that the interpolation we are speaking of is only
additive. It's not subtractive to not have the interpolation. Thus, from the
point of view of the amount of detail captured, it should not matter if the
camera is operated in grayscale mode or color, but tonality may definitely
be affected.

Todd

Todd Flashner wrote:

>  on 2/7/02 12:53 AM, SKID Photography wrote:
>
> >> What I took from my question to Austin (Horses Mouth, about a week ago) is
> >> that these one shot cameras interpolate color, not detail.
> >>
> > I do not understand how one can separate 'color' information and 'detail'?
> > They are one and the same.  It's not like there are separate or different
> > parts that make up the image.
>
> Say your sensor is a grid of two sensors across by two down. In grayscale
> mode you get a 4 pixel capture. You have 4 pixels of detail, represented by
> one channel which has 4 pixels.
>
> If the camera then applies an algorithm to give each of those pixels an RGB
> component, that requires interpolation, and you'll end up 3 channels at 4
> pixels each.

Stop right there and you have your answer.  INTERPOLATED INFORMATION!
Not reality.  End of more real information.

Harvey Ferdschneider
partner, SKID Photography, NYC



[Non-text portions of this message have been removed]

I see. So without interpolation my little 4 pixel grid would be analogous to
putting on a camera lens a filter which is split into 4 quadrants of color,
which would give wacky data.

Then how is grayscale handled? Are every 4 sensors averaged into one, or is
interpolation done for each sensor individually?

Todd

> But in a typical digital camera there's a color filter placed over the chip
> such that your 4 pixel grid would be:
> 
> [R][G]
> [G][B]
> 
> ...so there's no way to take a pure grayscale image, because there's a color
> filter stuck on the chip. The camera can't not interpolate in greyscale
> mode, because the only data it's capable of capturing is alread filtered for
> color. See: http://www.foveon.com/interp.html
> 
> -Jason
> 
>> -----Original Message-----
>> From: Todd Flashner [mailto:tflash@...]
>> Sent: Thursday, February 07, 2002 1:23 AM
>> To: DigitalBlackandWhiteThePrint@yahoogroups.com
>> Subject: Re: [Digital BW] Re: Digicam in BW mode, how to test
>> 
>> Say your sensor is a grid of two sensors across by two down. In grayscale
>> mode you get a 4 pixel capture. You have 4 pixels of detail,
>> represented by
>> one channel which has 4 pixels.
>> 
>> If the camera then applies an algorithm to give each of those
>> pixels an RGB
>> component, that requires interpolation, and you'll end up 3 channels at 4
>> pixels each. You've added color channels, through interpolation, which may
>> or may not contain an accurate representation of the color they
>> are tying to
>> create, but you've added no detail.
> 
> 
> 
> 
> Please visit the Group Homepage to check the Files, Bookmarks, Polls and other
> resources as they are often being updated. The page is at:
> 
> http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint
> 
> Please follow these basic guidelines:
> - Include your full name with your message.
> - Include the address of your website, if you have one.
> - As threads develop, trim off excess portions of earlier messages to keep
> them short.
> - As the topic of a thread changes remember to change the subject header.
> - Good manners are required at all time. No personal attacks or "flames."
> - Complete your Yahoo profile.
> - Before posting a question, search the message archives and the various
> resources on the homepage.
> 
> 
> 
> 
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> 
>

Todd,
My understanding of the interpolation is that it takes the specific color
information from the one sensor, and then it 'borrows' some data from the
surrounding sensors to finish out the information it needs to make the pixel.

And although it's a sophisticated algorithm, it's still made up information, not
reality.  And that is why there is not as much detail in a digital camera
captures as a scanned film file of the same resolution.

Harvey Ferdschneider
partner, SKID Photography, NYC



>  I see. So without interpolation my little 4 pixel grid would be analogous to
> putting on a camera lens a filter which is split into 4 quadrants of color,
> which would give wacky data.
>
> Then how is grayscale handled? Are every 4 sensors averaged into one, or is
> interpolation done for each sensor individually?
>
> Todd
>
> > But in a typical digital camera there's a color filter placed over the chip
> > such that your 4 pixel grid would be:
> >
> > [R][G]
> > [G][B]
> >
> > ...so there's no way to take a pure grayscale image, because there's a color
>
> > filter stuck on the chip. The camera can't not interpolate in greyscale
> > mode, because the only data it's capable of capturing is alread filtered for
>
> > color. See: http://www.foveon.com/interp.html
> >
> > -Jason
> >
> >> -----Original Message-----
> >> From: Todd Flashner [mailto:tflash@...]
> >> Sent: Thursday, February 07, 2002 1:23 AM
> >> To: DigitalBlackandWhiteThePrint@yahoogroups.com
> >> Subject: Re: [Digital BW] Re: Digicam in BW mode, how to test
> >>
> >> Say your sensor is a grid of two sensors across by two down. In grayscale
> >> mode you get a 4 pixel capture. You have 4 pixels of detail,
> >> represented by
> >> one channel which has 4 pixels.
> >>
> >> If the camera then applies an algorithm to give each of those
> >> pixels an RGB
> >> component, that requires interpolation, and you'll end up 3 channels at 4
> >> pixels each. You've added color channels, through interpolation, which may
> >> or may not contain an accurate representation of the color they
> >> are tying to
> >> create, but you've added no detail.
>





[Non-text portions of this message have been removed]

on 2/7/02 1:57 AM, SKID Photography wrote:

>>>> What I took from my question to Austin (Horses Mouth, about a week ago) is
>>>> that these one shot cameras interpolate color, not detail.
>>>> 
>>> I do not understand how one can separate 'color' information and 'detail'?
>>> They are one and the same.  It's not like there are separate or different
>>> parts that make up the image.
>> 
>> Say your sensor is a grid of two sensors across by two down. In grayscale
>> mode you get a 4 pixel capture. You have 4 pixels of detail, represented by
>> one channel which has 4 pixels.
>> 
>> If the camera then applies an algorithm to give each of those pixels an RGB
>> component, that requires interpolation, and you'll end up 3 channels at 4
>> pixels each.
> 
> Stop right there and you have your answer.  INTERPOLATED INFORMATION!
> Not reality.  End of more real information.

Well, it depends on how literal we want to be. See, I think I'm correct in
an absolute sense, just not a practical sense. I not clear on how these
cameras work in grayscale, so I would forget anything I've said as it
relates to one shot cameras, but we could discuss this on a pure digital
science level (not that we should need to or want to), where I am
"technically" correct (to the best of my knowledge ;-)).

Let me just expound a bit, then we can continue, or drop it.

Above you asked how we can separate "color" from "detail" as they are one
and the same. Well we can and they're not. Austin used the right terms,
chrominance and luminance - they are different. Convert an RGB image to Lab
mode and you will have separated the two. The Luminance will live in the L
channel, and the chrominance in the a & b channels. look at each channel
individually. The L channel is a grayscale image which has virtually all the
detail, the a & B channels hold the color, and they are mush. So the context
in which I discussed "detail" is as it relates to luminance.

Then you say interpolation is the end of real information. That's true by
definition, but has no relevance to luminance, and "information" is a vague
term which I never used as it has not been defined. My point is that these
one shot cameras do record a luminance value at each sensor, thus detail,
and it is the chrominance which is interpolated.

The problem is that with the color filter on each sensor the luminance
(detail) values will be somewhat arbitrary at each pixel in a real world
imaging sense.

Todd

> Todd,
> My understanding of the interpolation is that it takes the specific color
> information from the one sensor, and then it 'borrows' some data from the
> surrounding sensors to finish out the information it needs to make the pixel.

That sounds familiar.
 
> And although it's a sophisticated algorithm, it's still made up information,
> not
> reality.  And that is why there is not as much detail in a digital camera
> captures as a scanned film file of the same resolution.

That I never disputed. My only point was that each sensor did record detail,
which it does, but I was forgetting that each sensor has a filter over it.
Thus, although I'm *technically* correct that they each record detail, that
detail isn't useable as is (because of the filters) and needs to be factored
with the other sensors as you state above.

Never mind. ;-)

Todd

> 
>> I see. So without interpolation my little 4 pixel grid would be analogous to
>> putting on a camera lens a filter which is split into 4 quadrants of color,
>> which would give wacky data.
>> 
>> Then how is grayscale handled? Are every 4 sensors averaged into one, or is
>> interpolation done for each sensor individually?
>> 
>> Todd
>> 
>>> But in a typical digital camera there's a color filter placed over the chip
>>> such that your 4 pixel grid would be:
>>> 
>>> [R][G]
>>> [G][B]
>>> 
>>> ...so there's no way to take a pure grayscale image, because there's a color
>> 
>>> filter stuck on the chip. The camera can't not interpolate in greyscale
>>> mode, because the only data it's capable of capturing is alread filtered for
>> 
>>> color. See: http://www.foveon.com/interp.html
>>> 
>>> -Jason
>>> 
>>>> -----Original Message-----
>>>> From: Todd Flashner [mailto:tflash@...]
>>>> Sent: Thursday, February 07, 2002 1:23 AM
>>>> To: DigitalBlackandWhiteThePrint@yahoogroups.com
>>>> Subject: Re: [Digital BW] Re: Digicam in BW mode, how to test
>>>> 
>>>> Say your sensor is a grid of two sensors across by two down. In grayscale
>>>> mode you get a 4 pixel capture. You have 4 pixels of detail,
>>>> represented by
>>>> one channel which has 4 pixels.
>>>> 
>>>> If the camera then applies an algorithm to give each of those
>>>> pixels an RGB
>>>> component, that requires interpolation, and you'll end up 3 channels at 4
>>>> pixels each. You've added color channels, through interpolation, which may
>>>> or may not contain an accurate representation of the color they
>>>> are tying to
>>>> create, but you've added no detail.
>> 
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
> 
> 
> 
> Please visit the Group Homepage to check the Files, Bookmarks, Polls and other
> resources as they are often being updated. The page is at:
> 
> http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint
> 
> Please follow these basic guidelines:
> - Include your full name with your message.
> - Include the address of your website, if you have one.
> - As threads develop, trim off excess portions of earlier messages to keep
> them short.
> - As the topic of a thread changes remember to change the subject header.
> - Good manners are required at all time. No personal attacks or "flames."
> - Complete your Yahoo profile.
> - Before posting a question, search the message archives and the various
> resources on the homepage.
> 
> 
> 
> 
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> 
>

> I do not understand how one can separate 'color' information and
> 'detail'?
>  They are one and the same. 

The difference is in the chrominance and luminance. You get 
far greater critical information from the luminance 
channel than from the chrominance channels. That's the 
reason they use 2 green receptors for every red and 
blue.  You can have a sharp picture with good luminance 
detail but look crappy from color smearing in the chroma 
channels.

it's also another good reason for only apply the unsharp 
mask to the luminance channel. 

Greg

Todd Flashner wrote:

>  on 2/7/02 1:57 AM, SKID Photography wrote:
>
> >>>> What I took from my question to Austin (Horses Mouth, about a week ago)
> is
> >>>> that these one shot cameras interpolate color, not detail.
> >>>>
> >>> I do not understand how one can separate 'color' information and 'detail'?
>
> >>> They are one and the same.  It's not like there are separate or different
> >>> parts that make up the image.
> >>
> >> Say your sensor is a grid of two sensors across by two down. In grayscale
> >> mode you get a 4 pixel capture. You have 4 pixels of detail, represented by
>
> >> one channel which has 4 pixels.
> >>
> >> If the camera then applies an algorithm to give each of those pixels an RGB
>
> >> component, that requires interpolation, and you'll end up 3 channels at 4
> >> pixels each.
> >
> > Stop right there and you have your answer.  INTERPOLATED INFORMATION!
> > Not reality.  End of more real information.
>
> Well, it depends on how literal we want to be. See, I think I'm correct in
> an absolute sense, just not a practical sense. I not clear on how these
> cameras work in grayscale, so I would forget anything I've said as it
> relates to one shot cameras, but we could discuss this on a pure digital
> science level (not that we should need to or want to), where I am
> "technically" correct (to the best of my knowledge ;-)).
>
> Let me just expound a bit, then we can continue, or drop it.
>
> Above you asked how we can separate "color" from "detail" as they are one
> and the same. Well we can and they're not. Austin used the right terms,
> chrominance and luminance - they are different. Convert an RGB image to Lab
> mode and you will have separated the two. The Luminance will live in the L
> channel, and the chrominance in the a & b channels. look at each channel
> individually. The L channel is a grayscale image which has virtually all the
> detail, the a & B channels hold the color, and they are mush. So the context
> in which I discussed "detail" is as it relates to luminance.
>
> Then you say interpolation is the end of real information. That's true by
> definition, but has no relevance to luminance, and "information" is a vague
> term which I never used as it has not been defined. My point is that these
> one shot cameras do record a luminance value at each sensor, thus detail,
> and it is the chrominance which is interpolated.
>
> The problem is that with the color filter on each sensor the luminance
> (detail) values will be somewhat arbitrary at each pixel in a real world
> imaging sense.
>
> Todd
>

Todd,
But the luminance is only captured for the specific color of the specific
sensor.  Which is only 1/3 of the information needed to be real.  For example,
the red sensor can only capture the 'luminance' of the red information, the rest
of the luminance information, once again, is interpolated and therefore made up.

Harvey Ferdschneider
partner, SKID Photography, NYC





[Non-text portions of this message have been removed]

Pics4U@... wrote:

>
> > I do not understand how one can separate 'color' information and
> > 'detail'?
> >  They are one and the same.
>
> The difference is in the chrominance and luminance. You get
> far greater critical information from the luminance
> channel than from the chrominance channels. That's the
> reason they use 2 green receptors for every red and
> blue.  You can have a sharp picture with good luminance
> detail but look crappy from color smearing in the chroma
> channels.
>
> it's also another good reason for only apply the unsharp
> mask to the luminance channel.
>
> Greg

But the luminance is only captured for the specific color of the specific
sensor.  Which is only 1/3 of the information needed to be real.  For example,
the red sensor can only capture the 'luminance' of the red information, the rest

of the luminance information, once again, is interpolated and therefore made up.

Harvey Ferdschneider
partner, SKID Photography, NYC


[Non-text portions of this message have been removed]

Harvey 

I don't think either of us know how these cameras handle grayscale mode,
which is what this has been about, so to reduce confusion, until further
info is supplied, I will bow out.

Todd

> Todd Flashner wrote:
> 
>> on 2/7/02 1:57 AM, SKID Photography wrote:
>> 
>>>>>> What I took from my question to Austin (Horses Mouth, about a week ago)
>> is
>>>>>> that these one shot cameras interpolate color, not detail.
>>>>>> 
>>>>> I do not understand how one can separate 'color' information and 'detail'?
>> 
>>>>> They are one and the same.  It's not like there are separate or different
>>>>> parts that make up the image.
>>>> 
>>>> Say your sensor is a grid of two sensors across by two down. In grayscale
>>>> mode you get a 4 pixel capture. You have 4 pixels of detail, represented by
>> 
>>>> one channel which has 4 pixels.
>>>> 
>>>> If the camera then applies an algorithm to give each of those pixels an RGB
>> 
>>>> component, that requires interpolation, and you'll end up 3 channels at 4
>>>> pixels each.
>>> 
>>> Stop right there and you have your answer.  INTERPOLATED INFORMATION!
>>> Not reality.  End of more real information.
>> 
>> Well, it depends on how literal we want to be. See, I think I'm correct in
>> an absolute sense, just not a practical sense. I not clear on how these
>> cameras work in grayscale, so I would forget anything I've said as it
>> relates to one shot cameras, but we could discuss this on a pure digital
>> science level (not that we should need to or want to), where I am
>> "technically" correct (to the best of my knowledge ;-)).
>> 
>> Let me just expound a bit, then we can continue, or drop it.
>> 
>> Above you asked how we can separate "color" from "detail" as they are one
>> and the same. Well we can and they're not. Austin used the right terms,
>> chrominance and luminance - they are different. Convert an RGB image to Lab
>> mode and you will have separated the two. The Luminance will live in the L
>> channel, and the chrominance in the a & b channels. look at each channel
>> individually. The L channel is a grayscale image which has virtually all the
>> detail, the a & B channels hold the color, and they are mush. So the context
>> in which I discussed "detail" is as it relates to luminance.
>> 
>> Then you say interpolation is the end of real information. That's true by
>> definition, but has no relevance to luminance, and "information" is a vague
>> term which I never used as it has not been defined. My point is that these
>> one shot cameras do record a luminance value at each sensor, thus detail,
>> and it is the chrominance which is interpolated.
>> 
>> The problem is that with the color filter on each sensor the luminance
>> (detail) values will be somewhat arbitrary at each pixel in a real world
>> imaging sense.
>> 
>> Todd
>> 
> 
> Todd,
> But the luminance is only captured for the specific color of the specific
> sensor.  Which is only 1/3 of the information needed to be real.  For example,
> the red sensor can only capture the 'luminance' of the red information, the
> rest
> of the luminance information, once again, is interpolated and therefore made
> up.
> 
> Harvey Ferdschneider
> partner, SKID Photography, NYC

I've been waiting for someone to write an article like this one, as I do not
have the time.  Thanks for the link!  Now my job of explaining this has been
reduced to a simple link ;-)

Austin

> But in a typical digital camera there's a color filter placed
> over the chip
> such that your 4 pixel grid would be:
>
> [R][G]
> [G][B]
>
> ...so there's no way to take a pure grayscale image, because
> there's a color
> filter stuck on the chip. The camera can't not interpolate in greyscale
> mode, because the only data it's capable of capturing is alread
> filtered for
> color. See: http://www.foveon.com/interp.html
>
> -Jason

Hi Harvey,

> And although it's a sophisticated algorithm...

Actually, it's REALLY simple, you'd be surprised.

Regards,

Austin

> Then how is grayscale handled? Are every 4 sensors averaged into
> one,

No, not typically...

> or is
> interpolation done for each sensor individually?

Yes.

It's not a straight forward problem.  Remember, each sensor from a quad RGBG
isn't looking at the exact same thing...so they are measuring different
"space", so to say.  That means you just can't necessarily "combine" the
four (three) color values...but on the other hand, none of the values are
really complete unto themselves.  Answer is, no matter what is done, it's
got to be processed...and in doing so, it makes it more so not reality,
though it may look great.

Austin

To jump back in, having learned a lot from this discussion.  Here's Canon 
tech support on BW with the G2:
-----------
Images taken directly with the camera will have finer details than one
that is converted in a software application. During the conversion some
of the detail will be lost.
-----------

I asked for clarification on how the camera actually makes captures the BW 
image.  What happens when the subject is something like a stop sign that 
would give very different output on the RGB channels?  Maybe Canon will 
address the questions of luminance, RGB, interpolation, etc.  Austin's 
remarks make me curious:
---------
 > And although it's a sophisticated algorithm...
Actually, it's REALLY simple, you'd be surprised.
--------
Bob


At 08:37 AM 2/7/2002, you wrote:

> > Then how is grayscale handled? Are every 4 sensors averaged into
> > one,
>
>No, not typically...
>
> > or is
> > interpolation done for each sensor individually?
>
>Yes.
>
>It's not a straight forward problem.  Remember, each sensor from a quad RGBG
>isn't looking at the exact same thing...so they are measuring different
>"space", so to say.  That means you just can't necessarily "combine" the
>four (three) color values...but on the other hand, none of the values are
>really complete unto themselves.  Answer is, no matter what is done, it's
>got to be processed...and in doing so, it makes it more so not reality,
>though it may look great.
>
>Austin

> I asked for clarification on how the camera actually makes 
> captures the BW 
> image.  What happens when the subject is something like a stop sign that 
> would give very different output on the RGB channels?  Maybe Canon will 
> address the questions of luminance, RGB, interpolation, etc.  Austin's 
> remarks make me curious:
> ---------
>  > And although it's a sophisticated algorithm...
> Actually, it's REALLY simple, you'd be surprised.
> --------
> Bob

Hi Bob,

My comment was about interpolation, not the B&W conversion.

Regards,

Austin

To all interested in the digital test:

I may be way off on Canon cameras, but I can speak pretty accurately 
for Nikon (D1 series, at least) (and I just bought a Canon S40 for a 
pocket sized alternative, so I will try to figure this out and get 
back here).

The best way to shoot BW is to shoot RAW color and then make changes 
by desaturating or conversion to grayscale (your own religious 
choice) with software on the computer rather than the camera. Bibble, 
Qimage, Nikon Capture are all great.

The concept is that the RAW file is the "negative" and you 
can "develop" it in the camera or on your pc. Most users of apps like 
Bibble claim much better results on the pc... Not to mention that you 
can also go back and "redevelop" if there are improvements in the 
software (Bibble generally has a couple a year that are free).

Tom O'Connell

TomOC@...
www.thomasoconnell.com

Answer: If you are shooting with any digital camera, you should be 
capturing images in color, regardless of the output. There is 
absolutely no advantages to using "Monochrome Mode" on digital 
cameras.
WHY: The majority of digital cameras, reflective scanners and some 
film scanners, scan in only one color to obtain a digitized black 
and white image from the original color photo. Green is the color 
used due to overall balance and detail. Red generally contains 
highlights and Blue contains much of the noise and artifacts, and 
therefore both are not used. As a result you have not captured all 
of the tonal information, infact you only got 1/3 of the info.

If digital cameras captured in "Monochrome Mode" utilizing three 
color channels, you still would not want to utilize this function 
(At least not all the time). Because this would be the equivelant of 
limiting yourself to one type of Black & White film. The camera 
would be generating the monochrome image based on predetermined 
ratios of Red, Green, and Blue color information. This is the same 
as using the Photoshop conversion to Grayscale(Image>Mode>Grayscale) 
which converts your RGB image to Grayscale based on the following 
calculations(Approx):Red=43 Green=32 Blue=25
This often produces an excellant image, however, not always! And you 
have no say over the process. It would be like only shooting Kodak T-
Max 100 without any filters...Always.

By capturing the image in color, you have captured all of the color 
and tonal information nessesary to create a monochrome image with 
any characteristics you want, based on the method of conversion you 
choose (I currently have 8 PS actions for different methods of 
converting).

Basically, "Monochrome Mode" is provided as a feature for marketing 
purposes. This mode was never expected to be utilized for fine 
photography, nor should it.

Best Regards,
cr


--- In DigitalBlackandWhiteThePrint@y..., bob geoghegan 
<bobgeo@d...> wrote:
> This may border on OT, but here goes...
> 
> I'm looking for suggestions on testing a digital camera's BW mode 
against 
> its color mode for BW output.  The question is: how does shooting 
in BW 
> mode compare to shooting in color & converting later?  Converting 
later has 
> the advantage of applying contrast filters after the fact.  Would 
BW mode 
> be likely to offer advantages in, say, sharpness or dynamic 
range?  How 
> would one test that?  In particular, what sort of test target 
would be best 
> for sharpness?  Maybe something with saturated reds, greens & 
blues 
> bordering each other to look for fringing.
> 
> The camera in question is a Canon G2.  It locks some functions 
in 'auto' 
> for BW mode -- e.g., exposure is program mode only.  At least the 
ISO 
> setting hold when switching to BW.  Low compression .jpg is the 
top quality 

> save option in BW where Color includes a RAW ccd output losslessly 
> compressed (about 2x the BW .jpg size).
> 
> Regards,
> Bob G

Answer: If you are shooting with any digital camera, you should be 
capturing images in color, regardless of the output. There is 
absolutely no advantages to using "Monochrome Mode" on digital 
cameras.
WHY: The majority of digital cameras, reflective scanners and some 
film scanners, scan in only one color to obtain a digitized black 
and white image from the original color photo. Green is the color 
used due to overall balance and detail. Red generally contains 
highlights and Blue contains much of the noise and artifacts, and 
therefore both are not used. As a result you have not captured all 
of the tonal information, infact you only got 1/3 of the info.

If digital cameras captured in "Monochrome Mode" utilizing three 
color channels, you still would not want to utilize this function 
(At least not all the time). Because this would be the equivelant of 
limiting yourself to one type of Black & White film. The camera 
would be generating the monochrome image based on predetermined 
ratios of Red, Green, and Blue color information. This is the same 
as using the Photoshop conversion to Grayscale(Image>Mode>Grayscale) 
which converts your RGB image to Grayscale based on the following 
calculations(Approx):Red=43 Green=32 Blue=25
This often produces an excellant image, however, not always! And you 
have no say over the process. It would be like only shooting Kodak T-
Max 100 without any filters...Always.

By capturing the image in color, you have captured all of the color 
and tonal information nessesary to create a monochrome image with 
any characteristics you want, based on the method of conversion you 
choose (I currently have 8 PS actions for different methods of 
converting).

Basically, "Monochrome Mode" is provided as a feature for marketing 
purposes. This mode was never expected to be utilized for fine 
photography, nor should it.

Best Regards,
cr

--- In DigitalBlackandWhiteThePrint@y..., bob geoghegan 
<bobgeo@d...> wrote:
> This may border on OT, but here goes...
> 
> I'm looking for suggestions on testing a digital camera's BW mode 
against 
> its color mode for BW output.  The question is: how does shooting 
in BW 
> mode compare to shooting in color & converting later?  Converting 
later has 
> the advantage of applying contrast filters after the fact.  Would 
BW mode 
> be likely to offer advantages in, say, sharpness or dynamic 
range?  How 
> would one test that?  In particular, what sort of test target 
would be best 
> for sharpness?  Maybe something with saturated reds, greens & 
blues 
> bordering each other to look for fringing.
> 
> The camera in question is a Canon G2.  It locks some functions 
in 'auto' 
> for BW mode -- e.g., exposure is program mode only.  At least the 
ISO 
> setting hold when switching to BW.  Low compression .jpg is the 
top quality 

> save option in BW where Color includes a RAW ccd output losslessly 
> compressed (about 2x the BW .jpg size).
> 
> Regards,
> Bob G

> WHY: The majority of digital cameras, reflective scanners and some
> film scanners, scan in only one color to obtain a digitized black
> and white image from the original color photo.

I do not believe that is true.  They actually use a percentage of each of
the three colors, and yes, green is typically the highest of the mix.  It
would be nice if the scanner interfaces did allow you to select you own
"mix".

I do agree that it's better to capture in color (for scanners that do not
have a REAL B&W mode, like the Leafscanner ;-) and convert in
PS...but...some scanners have done a great job at determining what "mix"
works best for their particular scanner...so my advice for scanners, is to
try it and see which works for you.

Austin

Austin Franklin wrote:

>
> > WHY: The majority of digital cameras, reflective scanners and some
> > film scanners, scan in only one color to obtain a digitized black
> > and white image from the original color photo.
>
> I do not believe that is true.  They actually use a percentage of each of
> the three colors, and yes, green is typically the highest of the mix.  It
> would be nice if the scanner interfaces did allow you to select you own
> "mix".
>
> I do agree that it's better to capture in color (for scanners that do not
> have a REAL B&W mode, like the Leafscanner ;-) and convert in
> PS...but...some scanners have done a great job at determining what "mix"
> works best for their particular scanner...so my advice for scanners, is to
> try it and see which works for you.
>
> Austin

Austin,
In our Howtek (drum), it appears that you have a choice of which PMT sensor
channel you want to use for the B&W capture, and I assumed that any scanner
would just use one of the 3 sensor channels to render grayscale.

Are you saying that the Leafscan uses a 4th sensor to scan grayscale?  I'm not
arguing, just curious.

Harvey Ferdschneider
partner, SKID Photography, NYC





[Non-text portions of this message have been removed]

> Basically, "Monochrome Mode" is provided as a feature for marketing
> purposes. This mode was never expected to be utilized for fine
> photography, nor should it.

True enough, although I've found monochrome mode great for *visualizing* a
scene in B&W.  It's better than squinting, or using an orange filter.  You
can always change the mode to color and re-shoot.

john

> Are you saying that the Leafscan uses a 4th sensor to scan
> grayscale?  I'm not
> arguing, just curious.

Why, yes, Harvey, I am saying the Leafscan uses a 4th "sensor" to scan
grayscale ;-)

Actually, it's not a fourth sensor, but a fourth filter, a Neutral Density
filter...  IMO, the Leafscan gives the best grayscale scans of any scanner
on, or off, the market.

Austin

Austin Franklin wrote:

>  > Are you saying that the Leafscan uses a 4th sensor to scan
> > grayscale?  I'm not
> > arguing, just curious.
>
> Why, yes, Harvey, I am saying the Leafscan uses a 4th "sensor" to scan
> grayscale ;-)
>
> Actually, it's not a fourth sensor, but a fourth filter, a Neutral Density
> filter...  IMO, the Leafscan gives the best grayscale scans of any scanner
> on, or off, the market.
>
> Austin

So does the leaf scanner make 3 passes for RGB?

Sorry....I know this is OT)

Harvey Ferdschneider
partner, SKID Photography, NYC








[Non-text portions of this message have been removed]

on 2/7/02 6:26 PM, crwaldvogel wrote:

> This is the same 
> as using the Photoshop conversion to Grayscale(Image>Mode>Grayscale)
> which converts your RGB image to Grayscale based on the following
> calculations(Approx):Red=43 Green=32 Blue=25

I think your overall message is right on.

 I'm curious though, where did you get these numbers? I've seen several
times that the PS formula is R=59 G=29 B=11. This was said to be Thomas
Knoll's (the original PS developer) formula for approximating Plus-x film
without filtration.

Todd

> >  > Are you saying that the Leafscan uses a 4th sensor to scan
> > > grayscale?  I'm not
> > > arguing, just curious.
> >
> > Why, yes, Harvey, I am saying the Leafscan uses a 4th "sensor" to scan
> > grayscale ;-)
> >
> > Actually, it's not a fourth sensor, but a fourth filter, a 
> Neutral Density
> > filter...  IMO, the Leafscan gives the best grayscale scans of 
> any scanner
> > on, or off, the market.
> >
> > Austin
> 
> So does the leaf scanner make 3 passes for RGB?

Yes.

> Sorry....I know this is OT)

Why?  I know THAT question was color, but still, it's scanner related...

Regards,

Austin

Austin-
This is partially a response and a question:
Are you saying that all scanners average the three channels? I agree 
that many do (especially film scanners), but my understanding is 
that most reflective scanners use a single channel.

Irregardless of the answer to that one... once you take an average 
of channels from the device, you have given up data and accepted the 
manufacturers estimation of what a good B&W reproduction is.

cr

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" 
<darkroom@i...> wrote:
> 
> > WHY: The majority of digital cameras, reflective scanners and 
some
> > film scanners, scan in only one color to obtain a digitized black
> > and white image from the original color photo.
> 
> I do not believe that is true.  They actually use a percentage of 
each of
> the three colors, and yes, green is typically the highest of the 
mix.  It
> would be nice if the scanner interfaces did allow you to select 
you own
> "mix".
> 
> I do agree that it's better to capture in color (for scanners that 
do not
> have a REAL B&W mode, like the Leafscanner ;-) and convert in
> PS...but...some scanners have done a great job at determining 
what "mix"
> works best for their particular scanner...so my advice for 
scanners, is to

> try it and see which works for you.
> 
> Austin

I found this empty cart/chip reset page after being referred by someone who 
works for this company:

http://www.colorbat.com/empty_cartridges.htm

Has anyone used this company's offerings?  The names they give to their 
products are really different!  I'm curious who's inks they are using.

All the best!

-Andy Darlow

Photography, Digital Print Consulting and Custom Editions
Andrew Darlow Images International, www.andydarlow.com
Author: Inkjet Tip of the Month Club (newsletter) 
To subscribe, send e-mail to: Inkjettips-subscribe@yahoogroups.com

Hi cr,

> Austin-
> This is partially a response and a question:
> Are you saying that all scanners average the three channels? I agree
> that many do (especially film scanners), but my understanding is
> that most reflective scanners use a single channel.

You could very well be right, I am only talking about film scanners.

> Irregardless of the answer to that one... once you take an average
> of channels from the device, you have given up data and accepted the
> manufacturers estimation of what a good B&W reproduction is.

Yes, that is why I suggested that manufacturers might want to allow that to
be able to be set by the user.

Austin