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2009-01-04 by dale40203
How does an RGB scanner determine Greyscale equivalents? Is there a formula it applies to the three components? If so, would the color "fringing" I see on some RGB scans contribute to a softening of Greyscale scans? The only way I can see to avoid this is for only one of the RGB components to be used, and I know that would not be an accurate representation of RGB translated into GS. Thanks, Dale Hoffman
2009-01-05 by outdoornm
Dale, I cannot speak to scanners specifically, but Photoshop converts to grayscale directly in the red channel. ie, Image>Mode>grayscale (100% red, 0% green, 0% blue) There are other ways to grayscale, using various values of red, green or blue, but I would suspect that scanners use the same 100% red channel method. Lincoln - In DigitalBlackandWhiteThePrint@yahoogroups.com, "dale40203" <dhoff@...> wrote: > > How does an RGB scanner determine Greyscale equivalents? Is there a formula it applies to > the three components? If so, would the color "fringing" I see on some RGB scans contribute to > a softening of Greyscale scans? > > The only way I can see to avoid this is for only one of the RGB components to be used, and I
> know that would not be an accurate representation of RGB translated into GS. > > Thanks, > Dale Hoffman >
2009-01-05 by Peter De Smidt
It depends on the scanning software. Some, like Vuescan, allows the user to choose which rgb channel is used to make the grayscale channel.
2009-01-05 by Bill Morse
I don't believe that's true. You can test this with a Channel Mix layer, just compare the conversion with and without. To the OP; if you have signifcant fringing, then it likely will affect the gray conversion as well as (though less than) the color image. That said, you're still much better off converting in PS than the scanner software, as there you have full control over the conversion process. Learn to use the channel mixer. Bill On Sun, Jan 4, 2009 at 10:36 PM, outdoornm <outdoornm@...> wrote: > Dale, > > ...Photoshop converts to grayscale directly in the > red channel. ie, Image>Mode>grayscale (100% red, 0% green, 0% blue) > > There are other ways to grayscale, using various values of red, green or > blue, but I would > suspect that scanners use the same 100% red channel method. > > Lincoln > > > - In DigitalBlackandWhiteThePrint@yahoogroups.com<DigitalBlackandWhiteThePrint%40yahoogroups.com>, > "dale40203" <dhoff@...> wrote: > > > > How does an RGB scanner determine Greyscale equivalents? Is there a > formula it applies > to > > the three components? If so, would the color "fringing" I see on some RGB > scans > contribute to > > a softening of Greyscale scans? > > > > The only way I can see to avoid this is for only one of the RGB > components to be used, > and I > > know that would not be an accurate representation of RGB translated into > GS. > > > > Thanks, > > Dale Hoffman > > > > > -- Regards, Bill Morse Wm. Morse Editions http://www.MorseEditions.com/ [Non-text portions of this message have been removed]
2009-01-05 by Steve Clark
My vote would be to scan B&W neg as a single channel on the scanner. Especially if it's a prosumer scanner. My reasoning would be the optics and ccd alignment on these scanners are compromised thus the "fringing". Also, the blue channel is usually a garbage channel contributing most of the noise that the scanner will add. So, if channel mixing, you would really want to zero blue out and fiddle with the red and green. Ideally a scanner with a visual (salmon) filter would be best, but I think those days are long gone. The argument for scanning in RGB would be that you can finesse the channels to get what you want. So, I guess you would have to evaluate your hardware by scrutinizing a bunch of scans to decide if the extra size, image processing and time are worth it. I operate a Hell S3900 drum that is about as well engineered a scanner as you can get, and I don't waste a bunch of space and time fiddling with RGB from B&W negs. I pick either the Red or Green channel. Just my 2 pence. Clark On Jan 5, 2009, at 5:39 AM, Bill Morse wrote: > I don't believe that's true. You can test this with a Channel Mix > layer, > just compare the conversion with and without. > > To the OP; if you have signifcant fringing, then it likely will > affect the > gray conversion as well as (though less than) the color image. That > said, > you're still much better off converting in PS than the scanner > software, as > there you have full control over the conversion process. Learn to > use the > channel mixer. > > Bill > > On Sun, Jan 4, 2009 at 10:36 PM, outdoornm <outdoornm@...> > wrote: > > > Dale, > > > > ...Photoshop converts to grayscale directly in the > > red channel. ie, Image>Mode>grayscale (100% red, 0% green, 0% blue) > > > > There are other ways to grayscale, using various values of red, > green or > > blue, but I would > > suspect that scanners use the same 100% red channel method. > > > > Lincoln > > > > > > - In > DigitalBlackandWhiteThePrint > @yahoogroups.com<DigitalBlackandWhiteThePrint%40yahoogroups.com>, > > "dale40203" <dhoff@...> wrote: > > > > > > How does an RGB scanner determine Greyscale equivalents? Is > there a > > formula it applies > > to > > > the three components? If so, would the color "fringing" I see on > some RGB > > scans > > contribute to > > > a softening of Greyscale scans? > > > > > > The only way I can see to avoid this is for only one of the RGB > > components to be used, > > and I > > > know that would not be an accurate representation of RGB > translated into > > GS. > > > > > > Thanks, > > > Dale Hoffman > > > > > > > > > > > -- > Regards, > > Bill Morse > Wm. Morse Editions > > http://www.MorseEditions.com/ > > [Non-text portions of this message have been removed] > > > [Non-text portions of this message have been removed]
2009-01-05 by Louis Dina
--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Bill Morse" <Bill.Morse@...> wrote: > > I don't believe that's true. You can test this with a Channel Mix > layer, just compare the conversion with and without. Correct, Bill. When converting from color to grayscale in Photoshop (using Desaturate or Mode : Grayscale), Photoshop takes its tonal values as follows: approximately 30% of the red channel, 60% of the green channel, and 10% of the blue channel. Works fine for some images, but lousy for others. "Usually", the green channel comes closest to the true tonality, but even that is a dangerous statement, depending on the colors and tonalities of the image. Green is also usually the least noisy channel, but again, not always. Blue is usually the noisiest. Channel Mixer, Calculations, Apply Image and numerous plugins do a good job on color to B&W conversion. You can also do quite a bit of tonal manipulation in LightRoom. Lou
2009-01-05 by Lincoln Michaud
It is true that the direct conversion to greyscale from RGB in Photoshop changes to the red channel. You can check this easily by: converting an image to greyscale in PS by: Image>mode>grayscale. Go to Edit and select 'change profile to rgb'. Go back to Mode>Channel mixer and you will see that the red channel is at 100% Don't know about scanners. Lincoln
2009-01-05 by Jules
I agree. Don't do the conversion with the scanner as it's software is poor compared to the ways in which PhotoShop can convert. Scan in full colour and import into PS first. Jules --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "outdoornm" <outdoornm@...> wrote: > > Dale, > > I cannot speak to scanners specifically, but Photoshop converts to grayscale directly in the > red channel. ie, Image>Mode>grayscale (100% red, 0% green, 0% blue) > > There are other ways to grayscale, using various values of red, green or blue, but I would > suspect that scanners use the same 100% red channel method. > > Lincoln > > > - In DigitalBlackandWhiteThePrint@yahoogroups.com, "dale40203" <dhoff@> wrote: > > > > How does an RGB scanner determine Greyscale equivalents? Is there a formula it applies > to > > the three components? If so, would the color "fringing" I see on some RGB scans > contribute to > > a softening of Greyscale scans? > > > > The only way I can see to avoid this is for only one of the RGB components to be used, > and I > > know that would not be an accurate representation of RGB translated into GS.
> > > > Thanks, > > Dale Hoffman > > >
2009-01-06 by E Neilsen
If you have PS CS3 or CS4 why would you even consider just hitting mode>grayscale when you could convert to B&W with image>adjustment>B&W complete with preset that you can load for yourself? As for just using the red channel? I don't think so. It just does sound right at all. Just did a screen capture of a red channel only B&W, and a convert to grayscale screen capture and the numbers don't match. Close but not a match. There are default setting lurking in PS and I think that you idea about what is being done there is just that. I'd ask some Adobe folks about it. As for scanning, you can use the channels for sharpening, noise control, etc in the scanner software. It is a whole new exposure of a scene. How would you like to render it? That is the first question and the beauty of it is there is no ONE answer, but many equally valid choices. Eric Neilsen Photo 4101 Commerce Street, Suite 9 Dallas, TX 75226 214 827-8301 http://ericneilsenphotography.com SKype ejprinter _____
From: DigitalBlackandWhiteThePrint@yahoogroups.com [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of Lincoln Michaud Sent: Monday, January 05, 2009 9:25 AM To: DigitalBlackandWhiteThePrint@yahoogroups.com Subject: [Digital BW] Re: B+W Scans from RGB Scanners It is true that the direct conversion to greyscale from RGB in Photoshop changes to the red channel. You can check this easily by: converting an image to greyscale in PS by: Image>mode>grayscale. Go to Edit and select 'change profile to rgb'. Go back to Mode>Channel mixer and you will see that the red channel is at 100% Don't know about scanners. Lincoln [Non-text portions of this message have been removed]
2009-01-06 by outdoornm
Eric, I'm not arguing that direct grayscaling is the best method. I am just stating what the default is in my CS2. If you do the check I mentioned it will show you that is exactly the case. I have also read it elsewhere, but I can't find reference to it at this point. You guys need to come up with some authentication for your opinion- it sounds to me like you just think it is improbable. Personally, I choose to use direct grayscale because you can drive yourself crazy seeing what tweak works the best using channel mixer. I have found it much more effective to convert to grayscale directly Image>mode>Grayscale and then work on the image in curves. I find it gives me much more control. You wouldn't think so, but for me, it does. Like anything in Photoshop there are many ways to achieve what you want. Regards, Lincoln --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "E Neilsen" <e.neilsen2@...> wrote:
> > If you have PS CS3 or CS4 why would you even consider just hitting > mode>grayscale when you could convert to B&W with image>adjustment>B&W > complete with preset that you can load for yourself? As for just using the > red channel? I don't think so. It just does sound right at all. > > > > Just did a screen capture of a red channel only B&W, and a convert to > grayscale screen capture and the numbers don't match. Close but not a match. > > > There are default setting lurking in PS and I think that you idea about what > is being done there is just that. I'd ask some Adobe folks about it. > > > > As for scanning, you can use the channels for sharpening, noise control, etc > in the scanner software. It is a whole new exposure of a scene. How would > you like to render it? That is the first question and the beauty of it is > there is no ONE answer, but many equally valid choices. > > > > > > Eric Neilsen Photo > > 4101 Commerce Street, Suite 9 > > Dallas, TX 75226 > > 214 827-8301 > > > > http://ericneilsenphotography.com > > SKype ejprinter > > > > _____ > > From: DigitalBlackandWhiteThePrint@...m > [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of Lincoln > Michaud > Sent: Monday, January 05, 2009 9:25 AM > To: DigitalBlackandWhiteThePrint@yahoogroups.com > Subject: [Digital BW] Re: B+W Scans from RGB Scanners > > > > It is true that the direct conversion to greyscale from RGB in > Photoshop changes to the red channel. You can check this easily by: > converting an image to greyscale in PS by: Image>mode>grayscale. Go > to Edit and select 'change profile to rgb'. Go back to Mode>Channel > mixer and you will see that the red channel is at 100% Don't know > about scanners. > > Lincoln > > > > > > [Non-text portions of this message have been removed] >
2009-01-07 by Eric Neilsen
Lincoln, I understand were not arguing, just stating observations. When I did my test of the screen capture done two ways; 1) using the convert to gray and screen capture that and 2) show only the red channel and screen capture that. I got two very different results. And I'd love to see an attributable adobe source that states that grayscale uses red channel only or as ??? suggested a % of R, %G, and small % B. I rarely use the convert to grayscale unless I'm in a hurry. Each conversion is specific to that image and what you want to do just as with each camera exposure can have a red filter or orange filter or. I have seen several people suggest that PS has a better conversion of RGB to grayscale than does the scanning software, but I have not seen them mention published test that show this. I have seen Epson and Imacon side by side at demo events and they would NOT make the best scan they could and show the difference. Why? Could it be that much of it is operator experience and an equal part software/hardware driven? Could have simply been time. Eric Eric Neilsen 4101 Commerce Street, Suite 9 Dallas, TX 75226 214-827-8301 www.ericneilsenphotography.com SKYPE ejprinter
From: DigitalBlackandWhiteThePrint@yahoogroups.com [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of outdoornm Sent: Tuesday, January 06, 2009 4:34 PM To: DigitalBlackandWhiteThePrint@yahoogroups.com Subject: [Digital BW] Re: B+W Scans from RGB Scanners Eric, I'm not arguing that direct grayscaling is the best method. I am just stating what the default is in my CS2. If you do the check I mentioned it will show you that is exactly the case. I have also read it elsewhere, but I can't find reference to it at this point. You guys need to come up with some authentication for your opinion- it sounds to me like you just think it is improbable. Personally, I choose to use direct grayscale because you can drive yourself crazy seeing what tweak works the best using channel mixer. I have found it much more effective to convert to grayscale directly Image>mode>Grayscale and then work on the image in curves. I find it gives me much more control. You wouldn't think so, but for me, it does. Like anything in Photoshop there are many ways to achieve what you want. Regards, Lincoln --- In DigitalBlackandWhiteThePrint@yahoogroups.com <mailto:DigitalBlackandWhiteThePrint%40yahoogroups.com> , "E Neilsen" <e.neilsen2@...> wrote: > > If you have PS CS3 or CS4 why would you even consider just hitting > mode>grayscale when you could convert to B&W with image>adjustment>B&W > complete with preset that you can load for yourself? As for just using the > red channel? I don't think so. It just does sound right at all. > > > > Just did a screen capture of a red channel only B&W, and a convert to > grayscale screen capture and the numbers don't match. Close but not a match. > > > There are default setting lurking in PS and I think that you idea about what > is being done there is just that. I'd ask some Adobe folks about it. > > > > As for scanning, you can use the channels for sharpening, noise control, etc > in the scanner software. It is a whole new exposure of a scene. How would > you like to render it? That is the first question and the beauty of it is > there is no ONE answer, but many equally valid choices. > . Image removed by sender. [Non-text portions of this message have been removed]
2009-01-07 by Tyler Boley
hey folks, it's well documented what the RGB combo is they use for straight grayscale conversion, I can't recall what it is though, it's a mix. I'm sure someone here knows... Tyler http://www.custom-digital.com/ --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Eric Neilsen" <e.neilsen2@...> wrote: > > Lincoln, I understand were not arguing, just stating observations. When I > did my test of the screen capture done two ways; 1) using the convert to > gray and screen capture that and 2) show only the red channel and screen > capture that. I got two very different results. And I'd love to see an > attributable adobe source that states that grayscale uses red channel only > or as ??? suggested a % of R, %G, and small % B. > > > > I rarely use the convert to grayscale unless I'm in a hurry. Each conversion > is specific to that image and what you want to do just as with each camera > exposure can have a red filter or orange filter or. > > > > I have seen several people suggest that PS has a better conversion of RGB to > grayscale than does the scanning software, but I have not seen them mention > published test that show this. I have seen Epson and Imacon side by side at > demo events and they would NOT make the best scan they could and show the > difference. Why? Could it be that much of it is operator experience and an > equal part software/hardware driven? Could have simply been time. > > > > Eric > > > > > > Eric Neilsen > > 4101 Commerce Street, Suite 9 > > Dallas, TX 75226 > > 214-827-8301 > > > > www.ericneilsenphotography.com > > SKYPE ejprinter > > > > From: DigitalBlackandWhiteThePrint@yahoogroups.com > [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of outdoornm > Sent: Tuesday, January 06, 2009 4:34 PM > To: DigitalBlackandWhiteThePrint@yahoogroups.com > Subject: [Digital BW] Re: B+W Scans from RGB Scanners > > > > Eric, > > I'm not arguing that direct grayscaling is the best method. I am just > stating what the > default is in my CS2. If you do the check I mentioned it will show you that > is exactly the > case. I have also read it elsewhere, but I can't find reference to it at > this point. You guys > need to come up with some authentication for your opinion- it sounds to me > like you just > think it is improbable. > > Personally, I choose to use direct grayscale because you can drive yourself > crazy seeing > what tweak works the best using channel mixer. I have found it much more > effective to > convert to grayscale directly Image>mode>Grayscale and then work on the > image in > curves. I find it gives me much more control. You wouldn't think so, but for > me, it does. > Like anything in Photoshop there are many ways to achieve what you want. > > Regards, > > Lincoln > > --- In DigitalBlackandWhiteThePrint@yahoogroups.com > <mailto:DigitalBlackandWhiteThePrint%40yahoogroups.com> , "E Neilsen" > <e.neilsen2@> > wrote: > > > > If you have PS CS3 or CS4 why would you even consider just hitting > > mode>grayscale when you could convert to B&W with image>adjustment>B&W > > complete with preset that you can load for yourself? As for just using the > > red channel? I don't think so. It just does sound right at all. > > > > > > > > Just did a screen capture of a red channel only B&W, and a convert to > > grayscale screen capture and the numbers don't match. Close but not a > match. > > > > > > There are default setting lurking in PS and I think that you idea about > what > > is being done there is just that. I'd ask some Adobe folks about it. > > > > > > > > As for scanning, you can use the channels for sharpening, noise control, > etc > > in the scanner software. It is a whole new exposure of a scene. How would > > you like to render it? That is the first question and the beauty of it is
> > there is no ONE answer, but many equally valid choices. > > > > > > . > > Image removed by sender. > > > > > [Non-text portions of this message have been removed] >
2009-01-07 by Eric Neilsen
Tyler, I asked my friend Dan Burkholder and here is his reply, Hey Eric, I asked Julianne Kost of Adobe that very question a few years ago and can't find her response. I'm pretty sure it was either 70G/20R/10B or 60G/30R/10B...but with my memory who knows. Guess you could manually do those and see which more closely matches the RGB>Grayscale conversion. But certainly not 100% red. Eric Neilsen 4101 Commerce Street, Suite 9 Dallas, TX 75226 214-827-8301 www.ericneilsenphotography.com SKYPE ejprinter
From: DigitalBlackandWhiteThePrint@yahoogroups.com [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of Tyler Boley Sent: Tuesday, January 06, 2009 9:03 PM To: DigitalBlackandWhiteThePrint@yahoogroups.com Subject: [Digital BW] Re: B+W Scans from RGB Scanners hey folks, it's well documented what the RGB combo is they use for straight grayscale conversion, I can't recall what it is though, it's a mix. I'm sure someone here knows... Tyler http://www.custom-digital.com/ _ [Non-text portions of this message have been removed]
2009-01-07 by John Vitollo
--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Eric Neilsen" <e.neilsen2@...> wrote: > I asked Julianne Kost of Adobe that very question a few years ago and can't > find her response. I'm pretty sure it was either 70G/20R/10B or > 60G/30R/10B...but with my memory who knows. Guess you could manually do > those and see which more closely matches the RGB>Grayscale conversion. Photoshop's default grayscale conversion is: R-30% G-60% B-10%
2009-01-07 by Ernst Dinkla
Eric Neilsen wrote: > I asked Julianne Kost of Adobe that very question a few years ago and can't > find her response. I'm pretty sure it was either 70G/20R/10B or > 60G/30R/10B...but with my memory who knows. Guess you could manually do > those and see which more closely matches the RGB>Grayscale conversion. That's what I recall of the Vuescan default settings for the greyscale scan mode, the green dominant in the mix. -- Met vriendelijke groeten, Ernst | Dinkla Grafische Techniek | | www.pigment-print.com | | ( unvollendet ) |
2009-01-08 by outdoornm
John, If that is true, why don't you see those values in the channel mixer of a directly grayscaled image? If you directly grayscale an image Image>Mode>Grayscale, you can no longer access the image via the channel mixer. However, If you change the profile of that same image to RGB and go back in thru' Image>Adjustments>Channel Mixer you will see that the default is 100% red. ????? Why doesn't it read R30% G60% B10% since those are supposed to be the values in each channel? Lincoln --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "John Vitollo" <jvlist@...> wrote:
> > --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Eric Neilsen" <e.neilsen2@> > wrote: > > I asked Julianne Kost of Adobe that very question a few years ago and can't > > find her response. I'm pretty sure it was either 70G/20R/10B or > > 60G/30R/10B...but with my memory who knows. Guess you could manually do > > those and see which more closely matches the RGB>Grayscale conversion. > > Photoshop's default grayscale conversion is: R-30% G-60% B-10% >
2009-01-08 by Louis Dina
Lincoln, Channel Mixer simply defaults to 100% of the red channel upon opening, but that doesn't mean it is the default B&W conversion formula for Photoshop. When you click 'grayscale' in Channel Mixer, it just jumps to the first available channel, which is red, and leaves it at 100% so you can start fiddling around with the sliders. That gives you a display of the Red channel only, with both Green and Blue channels set to 0%. It's just a blank canvas and a starting point. Looking at any grayscale conversion using Mode>Grayscale, you can see that the result is not the Red channel only. All the information I can find suggests 30%R, 60%G, 10%B is about right for a standard mode change. If it isn't that, it is close. Sometimes a single channel provides the best conversion, or at least comes close to the desired result. It may be the red, green or blue channel, but usually it is some combination of at least two channels. Since Hue and Saturation are no longer relevant in B&W, it's a matter of selecting and blending those channels that give you the tonality distribution and separation you want between tones. And since we don't see in B&W, we get to select the relationships we want. Adobe decided 3/6/1 was a good "general" formula for the "average" mode conversion, but one size definitely does not fit all. Regards, Lou --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "outdoornm" <outdoornm@...> wrote: > > John, > > If that is true, why don't you see those values in the channel mixer of a directly grayscaled > image? If you directly grayscale an image Image>Mode>Grayscale, you can no longer > access the image via the channel mixer. However, If you change the profile of that same > image to RGB and go back in thru' Image>Adjustments>Channel Mixer you will see that > the default is 100% red. ????? Why doesn't it read R30% G60% B10% since those are > supposed to be the values in each channel? > > Lincoln > > > --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "John Vitollo" <jvlist@> wrote: > > > > --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Eric Neilsen" <e.neilsen2@> > > wrote: > > > I asked Julianne Kost of Adobe that very question a few years ago and can't > > > find her response. I'm pretty sure it was either 70G/20R/10B or > > > 60G/30R/10B...but with my memory who knows. Guess you could manually do > > > those and see which more closely matches the RGB>Grayscale conversion.
> > > > Photoshop's default grayscale conversion is: R-30% G-60% B-10% > > >
2009-01-08 by pr_roark
"Louis Dina" <lou@...> wrote: > ... All the information I can find suggests 30%R, 60%G, 10%B > is about right for a standard mode change. ... > Sometimes a single channel provides the best conversion, ... With my older DSLR, the blue channel was very noisy. With the new Canon 5D2, for at least some lenses, blue is sharper and noise free, at least outside the deep shadows. The shorter wavelengths are affected less by diffraction, so it makes sense blue would be sharper, all else being equal. > ... it's a matter of selecting and blending those channels > that give you the tonality distribution and separation you > want between tones. I split the RGB channels so that I can compare the B&W images of each. Then I clone/pull image information from each as needed. > Adobe decided 3/6/1 was a good "general" formula for the > "average" mode conversion, ... And often if there is no significant color information in the shot, I'll just use their mode change. It's easy. Paul www.PaulRoark.com
2009-01-08 by Dana H. Myers
Louis Dina wrote: > > > Lincoln, > > Channel Mixer simply defaults to 100% of the red channel upon opening, > but that doesn't mean it is the default B&W conversion formula for > Photoshop. When you click 'grayscale' in Channel Mixer, it just jumps > to the first available channel, which is red, and leaves it at 100% so > you can start fiddling around with the sliders. That gives you a > display of the Red channel only, with both Green and Blue channels set > to 0%. It's just a blank canvas and a starting point. > > Looking at any grayscale conversion using Mode>Grayscale, you can see > that the result is not the Red channel only. All the information I > can find suggests 30%R, 60%G, 10%B is about right for a standard mode > change. If it isn't that, it is close. According to _mastering black and white digital photography_ ( http://www.amazon.com/Mastering-Black-White-Digital-Photography/dp/1579907075 ), Photoshop uses 30% red, 59% green and 11% blue, which jives with the 30/60/10 number. Desaturate gives equal weight to all the channels. Dana
2009-01-08 by Eric Neilsen
I have done a bit more research on this and I think that the %s given might be old hat. The speed at which information changes from books, articles, even internet blogs, can be inaccurate. I checked with another source and a more current conversation indicates a reduction based on HSL; Hue saturation and Lightness. And with all the programs that are active; CS 1-4 and before it is quite possible that many answer will remain correct. I pointed this out about internet information in a previous thread and one member took great offense. But it remains a real aspect of the digital information and digital processes. The actual conversion is going to be an elusive answer unless some can get Adobe to post it for specific version unless that information is in Freeman's book. Eric Neilsen 4101 Commerce Street, Suite 9 Dallas, TX 75226 214-827-8301 www.ericneilsenphotography.com SKYPE ejprinter
From: DigitalBlackandWhiteThePrint@yahoogroups.com [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of Dana H. Myers Sent: Thursday, January 08, 2009 10:56 AM To: DigitalBlackandWhiteThePrint@yahoogroups.com Subject: Re: [Digital BW] Re: B+W Scans from RGB Scanners Louis Dina wrote: > According to _mastering black and white digital photography_ ( http://www.amazon.com/Mastering-Black-White-Digital-Photography/dp/157990707 5 ), Photoshop uses 30% red, 59% green and 11% blue, which jives with the 30/60/10 number. Desaturate gives equal weight to all the channels. Dana . Image removed by sender. [Non-text portions of this message have been removed]
2009-01-08 by Louis Dina
--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Eric Neilsen" <e.neilsen2@...> wrote: > > I have done a bit more research on this and I think that the %s given might > be old hat. Eric, I suspect you are right. I opened an sRGB color image in PSCS2 and made three duplicates. The first I converted to grayscale (Mode>Grayscale) using gamma 2.2 space. The 2nd duplicate used Hue/Saturation, and the saturation slider was totally desaturated. The 3rd duplicate used Channel Mixer and I played around with the sliders. The mode conversion and desatuated images were totally different. Channel Mixer did not match either when set to 30R, 59G, 11B. In fact, it was tough to duplicate the mode conversion without also adjusting the "constant" slider, and even that was just close. To me, it is a moot point, since I rarely find that any of the default conversions work well (unless, as Paul Roark pointed out, you are starting with a relatively low key image to begin with). Sometimes a single channel works, but I find I need to blend channels to get a grayscale image that works. Lou
2009-01-08 by outdoornm
Thank you, Lou, What you say, makes sense. I could see the diff' between direct grayscaling and running 100% red in the channel mixer, but I thought that was because Photoshop was automatically adjusting for the luminescence values. I assume from what you are saying that Photoshop has some set ratio(possibly 30%R, 60%G and 10%B) However, If one wishes to modify the results he can use the channel mixer. It would be good to get the actual percentages from Adobe so that we would all know the actual percentages without guessing. Well, they don't call Photoshop the most complicated software system on earth for nothing. I thought the 'learning curve' would flatten out after a while. :-) Lincoln
> Lincoln, > > Channel Mixer simply defaults to 100% of the red channel upon opening, > but that doesn't mean it is the default B&W conversion formula for > Photoshop. When you click 'grayscale' in Channel Mixer, it just jumps > to the first available channel, which is red, and leaves it at 100% so > you can start fiddling around with the sliders. That gives you a > display of the Red channel only, with both Green and Blue channels set > to 0%. It's just a blank canvas and a starting point. > > Looking at any grayscale conversion using Mode>Grayscale, you can see > that the result is not the Red channel only. All the information I > can find suggests 30%R, 60%G, 10%B is about right for a standard mode > change. If it isn't that, it is close. > > Sometimes a single channel provides the best conversion, or at least > comes close to the desired result. It may be the red, green or blue > channel, but usually it is some combination of at least two channels. > Since Hue and Saturation are no longer relevant in B&W, it's a matter > of selecting and blending those channels that give you the tonality > distribution and separation you want between tones. And since we > don't see in B&W, we get to select the relationships we want. Adobe > decided 3/6/1 was a good "general" formula for the "average" mode > conversion, but one size definitely does not fit all. > > Regards, Lou > > > --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "outdoornm" > <outdoornm@> wrote: > > > > John, > > > > If that is true, why don't you see those values in the channel mixer > of a directly grayscaled > > image? If you directly grayscale an image Image>Mode>Grayscale, you > can no longer > > access the image via the channel mixer. However, If you change the > profile of that same > > image to RGB and go back in thru' Image>Adjustments>Channel Mixer > you will see that > > the default is 100% red. ????? Why doesn't it read R30% G60% B10% > since those are > > supposed to be the values in each channel? > > > > Lincoln > > > > > > --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "John Vitollo" > <jvlist@> wrote: > > > > > > --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Eric > Neilsen" <e.neilsen2@> > > > wrote: > > > > I asked Julianne Kost of Adobe that very question a few years > ago and can't > > > > find her response. I'm pretty sure it was either 70G/20R/10B or > > > > 60G/30R/10B...but with my memory who knows. Guess you could > manually do > > > > those and see which more closely matches the RGB>Grayscale > conversion. > > > > > > Photoshop's default grayscale conversion is: R-30% G-60% B-10% > > > > > >
2009-01-08 by Louis Dina
--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "outdoornm" <outdoornm@...> wrote: > > Thank you, Lou, > > I assume from what you are saying that Photoshop has some set >ratio(possibly 30%R, 60%G and 10%B) You're welcome. Glad it was clear. Not so sure that the 30/60/10 balance is correct, even though it has circulated in many forums and become widely accepted as true. http://tech.groups.yahoo.com/group/DigitalBlackandWhiteThePrint/message/94784 Lou
2009-01-09 by Steve Clark
It seems you could test it by creating an RGB document with solid 100% Red, Green and Blue bands that do not overlap and then do Mode>Greyscale. Then eyedropper the resultant greyscale in each of the corresponding bands. Clark On Jan 8, 2009, at 9:42 AM, Eric Neilsen wrote: > I have done a bit more research on this and I think that the %s > given might > be old hat. The speed at which information changes from books, > articles, > even internet blogs, can be inaccurate. I checked with another > source and a > more current conversation indicates a reduction based on HSL; Hue > saturation and Lightness. > > And with all the programs that are active; CS 1-4 and before it is > quite > possible that many answer will remain correct. I pointed this out > about > internet information in a previous thread and one member took great > offense. > But it remains a real aspect of the digital information and digital > processes. The actual conversion is going to be an elusive answer > unless > some can get Adobe to post it for specific version unless that > information > is in Freeman's book. > > Eric Neilsen > > 4101 Commerce Street, Suite 9 > > Dallas, TX 75226 > > 214-827-8301 > > www.ericneilsenphotography.com > > SKYPE ejprinter > > From: DigitalBlackandWhiteThePrint@yahoogroups.com > [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of > Dana H. > Myers > Sent: Thursday, January 08, 2009 10:56 AM > To: DigitalBlackandWhiteThePrint@...m > Subject: Re: [Digital BW] Re: B+W Scans from RGB Scanners > > Louis Dina wrote: > > > > According to _mastering black and white digital photography_ ( > http://www.amazon.com/Mastering-Black-White-Digital-Photography/dp/157990707 > 5 ), > Photoshop uses 30% red, 59% green and 11% blue, which jives with > the 30/60/10 number. Desaturate gives equal weight to all the > channels. > > Dana > > . > > Image removed by sender. > > > [Non-text portions of this message have been removed] > > > [Non-text portions of this message have been removed]
2009-01-10 by br80906
Please check out this page...it helped me a ton on b/w conversion. You need to experiment w/your scanner, but the end result will give you what you are looking for... http://www.butzi.net/articles/colorscan.htm
2009-01-10 by Roy Harrington
--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "John Vitollo" <jvlist@...> wrote: > > --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Eric Neilsen" <e.neilsen2@> > wrote: > > I asked Julianne Kost of Adobe that very question a few years ago and can't > > find her response. I'm pretty sure it was either 70G/20R/10B or > > 60G/30R/10B...but with my memory who knows. Guess you could manually do > > those and see which more closely matches the RGB>Grayscale conversion. > > Photoshop's default grayscale conversion is: R-30% G-60% B-10% > There are no fixed ratios. Photoshop uses color management to convert Modes. So if you convert RGB to Grayscale you are preserving the L values of the RGB profile space -- converting them to identical L values in the grayscale working space. This is easy to see: take any set of RGB patches, using the eyedropper look at the L values, convert to grayscale and all the L values remain the same. Conversions using desaturate, channel mixer, black&white, I think use ratios but they are all different. Roy
2009-01-10 by Eric Neilsen
What I find interesting is no conversation about refocusing the scanner. While we know that RGB channels don't always focus at the same distance, isn't it possible that the real difference is simply a matter of how the focus was achieved? And has really nothing to do with a superior channel for the conversion. It might be a sensor issue which was discussed. And the stouffers step wedge is a Tech Pan film stock, or at least they were made from that, it may also be allowing light to pass differently than Elfe, Adox, Ilford, etc. And Roy, Do you know for what version of PS your information pertains to? All? Personal testing is still the order of the day. Eric Neilsen Photography 4101 Commerce Street Suite 9 Dallas, TX 75226 http://e.neilsen.home.att.net http://ericneilsenphotography.com Skype ejprinter
From: DigitalBlackandWhiteThePrint@yahoogroups.com [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of br80906 Sent: Friday, January 09, 2009 9:59 PM To: DigitalBlackandWhiteThePrint@yahoogroups.com Subject: [Digital BW] Re: B+W Scans from RGB Scanners Please check out this page...it helped me a ton on b/w conversion. You need to experiment w/your scanner, but the end result will give you what you are looking for... http://www.butzi.net/articles/colorscan.htm [Non-text portions of this message have been removed]
2009-01-10 by Roy Harrington
--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Eric Neilsen" <e.neilsen2@...> wrote: > ... > > > And Roy, Do you know for what version of PS your information pertains to? > All? Hi Eric, Color Management has been used for Photoshop Mode conversions for quite a while. At least all the CS versions (CS,CS2,CS3,CS4) do it that way. It's also worth mentioning that the Info Palette also uses this. If you display say RGB values when you have a grayscale file, you are seeing the ICC converted values based on the RGB working space. In other words since K values are displayed in values 0-100 you don't see the full 8 bits that are really there. Often people will look at the RGB values 0-255. But they aren't the files values they are the converted values from K to RGB -- matching Lab Luminosity. Roy > > > Personal testing is still the order of the day. > Yes, testing is always worthwhile. It's a great way to learn what's going on "under the hood" -- if you are curious about it. R
> > > > Eric Neilsen Photography > > 4101 Commerce Street > > Suite 9 > > Dallas, TX 75226 > > http://e.neilsen.home.att.net > > http://ericneilsenphotography.com > > Skype ejprinter > > From: DigitalBlackandWhiteThePrint@yahoogroups.com > [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of br80906 > Sent: Friday, January 09, 2009 9:59 PM > To: DigitalBlackandWhiteThePrint@yahoogroups.com > Subject: [Digital BW] Re: B+W Scans from RGB Scanners > > > > Please check out this page...it helped me a ton on b/w conversion. > You need to experiment w/your scanner, but the end result will give > you what you are looking for... > > http://www.butzi.net/articles/colorscan.htm > > > > > > [Non-text portions of this message have been removed] >
2009-01-10 by Roy Harrington
--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Eric Neilsen" <e.neilsen2@...> wrote: > ... > > > And Roy, Do you know for what version of PS your information pertains to? > All? Hi Eric, Color Management has been used for Photoshop Mode conversions for quite a while. At least all the CS versions (CS,CS2,CS3,CS4) do it that way. It's also worth mentioning that the Info Palette also uses this. If you display say RGB values when you have a grayscale file, you are seeing the ICC converted values based on the RGB working space. In other words since K values are displayed in values 0-100 you don't see the full 8 bits that are really there. Often people will look at the RGB values 0-255. But they aren't the files values they are the converted values from K to RGB -- matching Lab Luminosity. Roy > > > Personal testing is still the order of the day. > Yes, testing is always worthwhile. It's a great way to learn what's going on "under the hood" -- if you are curious about it. R
> > > > Eric Neilsen Photography > > 4101 Commerce Street > > Suite 9 > > Dallas, TX 75226 > > http://e.neilsen.home.att.net > > http://ericneilsenphotography.com > > Skype ejprinter > > From: DigitalBlackandWhiteThePrint@yahoogroups.com > [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of br80906 > Sent: Friday, January 09, 2009 9:59 PM > To: DigitalBlackandWhiteThePrint@yahoogroups.com > Subject: [Digital BW] Re: B+W Scans from RGB Scanners > > > > Please check out this page...it helped me a ton on b/w conversion. > You need to experiment w/your scanner, but the end result will give > you what you are looking for... > > http://www.butzi.net/articles/colorscan.htm > > > > > > [Non-text portions of this message have been removed] >
2009-01-10 by Eric Neilsen
Roy, Yes, Color management has been a round in PS for many generations. And the values to look at are not just the RGB values. But that doesn't answer the question of, "Has the conversion to grayscale been the same from PS6 through CS4 the same"?. Are those stating the best way to scan is from RGB convert to gray in PS talking about a particular workflow; scanner, software with Version, PS what version, etc. Without the stated workflow, the answers may not be valid today with the next users workflow. The issue surrounding what conversion method Adobe uses when applying convert to gray have presented themselves because we have received various answers without a version and source. I have contacted several people that work in the industry and have either direct working relationships with Adobe or deal with writing plug ins for Adobe products. I have received indications that at one point they used a conversion that included the RGB % values that were stated. It was expressed to me that at some point that was true, but has since changed to more of the HSL conversion method. I really don't care as I use other methods to convert a RGB file to a K. Rereading the answer to the OP, Peter answered it; it depends on the software. But I also say what hardware too. The thread moved away from just what the scanner does to how PS converts to gray -K. Including references to books, contacts, etc and we have several in the specific values camp of RGB and some that are in the HSL camp. I am saying it sounds that both are valid for various times in the life of Adobe PS. And now we have Lightroom that will take a scan and whether it was output from the scanner with a gamma 2.2 or whatever, will output it as an RGB file to PS and beyond. So to Dale, run tests in the scanning software to determine what works best for your set up paying attention to the controls available for noise, focus, etc. All things that contribute to the proper exposure for your image intent. Eric Neilsen 4101 Commerce Street, Suite 9 Dallas, TX 75226 214-827-8301 www.ericneilsenphotography.com SKYPE ejprinter
From: DigitalBlackandWhiteThePrint@yahoogroups.com [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of Roy Harrington Sent: Saturday, January 10, 2009 12:23 PM To: DigitalBlackandWhiteThePrint@yahoogroups.com Subject: [Digital BW] Re: B+W Scans from RGB Scanners --- In DigitalBlackandWhiteThePrint@yahoogroups.com <mailto:DigitalBlackandWhiteThePrint%40yahoogroups.com> , "Eric Neilsen" <e.neilsen2@...> wrote: > ... > > > And Roy, Do you know for what version of PS your information pertains to? > All? Hi Eric, Color Management has been used for Photoshop Mode conversions for quite a while. At least all the CS versions (CS,CS2,CS3,CS4) do it that way. It's also worth mentioning that the Info Palette also uses this. If you display say RGB values when you have a grayscale file, you are seeing the ICC converted values based on the RGB working space. In other words since K values are displayed in values 0-100 you don't see the full 8 bits that are really there. Often people will look at the RGB values 0-255. But they aren't the files values they are the converted values from K to RGB -- matching Lab Luminosity. Roy > > > Personal testing is still the order of the day. > Yes, testing is always worthwhile. It's a great way to learn what's going on "under the hood" -- if you are curious about it. R > > > > Eric Neilsen Photography > > 4101 Commerce Street > > Suite 9 > > Dallas, TX 75226 > > http://e.neilsen.home.att.net > > http://ericneilsenphotography.com > > Skype ejprinter > > From: DigitalBlackandWhiteThePrint@yahoogroups.com <mailto:DigitalBlackandWhiteThePrint%40yahoogroups.com> > [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com <mailto:DigitalBlackandWhiteThePrint%40yahoogroups.com> ] On Behalf Of br80906 > Sent: Friday, January 09, 2009 9:59 PM > To: DigitalBlackandWhiteThePrint@yahoogroups.com <mailto:DigitalBlackandWhiteThePrint%40yahoogroups.com> > Subject: [Digital BW] Re: B+W Scans from RGB Scanners > > > > Please check out this page...it helped me a ton on b/w conversion. > You need to experiment w/your scanner, but the end result will give > you what you are looking for... > > http://www.butzi.net/articles/colorscan.htm > > > > > > [Non-text portions of this message have been removed] > [Non-text portions of this message have been removed]