Digital BW, The Print

When calibrating a crt monitor (I guess a lcd is different?) on a PC 
running windows what settings should be used. According to computer-
darkroom/Ian Lyons, using OptiCal the Luminance white & black points 
are set to .3 and 90. The col temp to 6500K and the Gamma for a PC 2.2

Could the col temp be set at 5000K which I think is more of an 
industry standard. I think that prints should be viewed under the 
same light temperature as the monitor is set to?

For PC 's is the gamma standard 2.2 ? And for Macs 1.8 ?
What if I need to work with someone (provide files) who is printing 
from a mac, should my pc be set to 1.8 too or will the 
platforms 'talk to each other' if I'm on 2.2 and he is on 1.8 ?

And the white and black luminance points  .3 and 90 that are 
recommended..are these standards or ....???

thanks

When calibrating a crt monitor (I guess a lcd is different?) on a PC 
running windows what settings should be used. According to computer-
darkroom/Ian Lyons, using OptiCal the Luminance white & black points 
are set to .3 and 90. The col temp to 6500K and the Gamma for a PC 2.2

Could the col temp be set at 5000K which I think is more of an 
industry standard. I think that prints should be viewed under the 
same light temperature as the monitor is set to?

For PC 's is the gamma standard 2.2 ? And for Macs 1.8 ?
What if I need to work with someone (provide files) who is printing 
from a mac, should my pc be set to 1.8 too or will the 
platforms 'talk to each other' if I'm on 2.2 and he is on 1.8 ?

And the white and black luminance points  .3 and 90 that are 
recommended..are these standards or ....???

thanks

On the subject of white point settings, I use 5000 K for the reason you
mentioned - that it is an industry standard for viewing.  I often have to
make files and prints that match slides, transparencies, or original
artwork, and have a GTI Softview viewer near my computer that allows me to
either use 5000 K reflected light or 5000 K light from behind to see
slides/film.  Many people seem to choose 6500 K because they feel it is
brighter and not that much different, but I find for critical purposes my
setup serves me well.  I'll be curious to see what the reasons are for other
choices!

P.S. - Obviously if you are making a print that will be seen under something
other than 5000 K light, you need to have a profile, curve, or make some
adjustments that take the final color temperature of that light into
account.  But to use the 5000 K matching as a starting point gives me a base
file that I can tailor to other uses, if necessary.

> From: frankg_photo [mailto:fh.gross@...]
>
> When calibrating a crt monitor (I guess a lcd is different?) on a PC
> running windows what settings should be used. According to computer-
> darkroom/Ian Lyons, using OptiCal the Luminance white & black points
> are set to .3 and 90. The col temp to 6500K and the Gamma for a PC 2.2

Some people swear by 6500K, even though their viewing lamps are closer to
5000K. Personally, I like having them match. I use Solux halogens, and have
tweaked the line voltage with a variac to get 5000K at the viewing surface,
measured with an Eye-One, and the match between that and my CRT is
excellent.

> For PC 's is the gamma standard 2.2 ? And for Macs 1.8 ?
> What if I need to work with someone (provide files) who is printing
> from a mac, should my pc be set to 1.8 too or will the
> platforms 'talk to each other' if I'm on 2.2 and he is on 1.8 ?

The whole point of profiles is that it doesn't matter how you calibrate your
monitor. The monitor settings only affects non-color-managed stuff in
Windows, like Internet Explorer, your wallpaper, and the window borders. The
Mac, as I understand it, is completely color-managed, so the profile will
provide the correct appearance even in web browsers.

> And the white and black luminance points  .3 and 90 that are
> recommended..are these standards or ....???

I like getting the monitor as bright as I can, but my monitor's power
supplies are a bit weak. If I crank the brightness (actually the Contrast
knob) all the way, the power supply sags depending upon how much white is on
the screen, which makes it totally impossible to calibrate the monitor. So
what I do is put up a black background, then put a small white square on the
corner of it (you can use Photoshop or Paint). Then, I opened up a Notepad
window to fill most of the screen with white, but leaving the white square
uncovered. Then, I watched the small white square while I alternately
minimized and restored the Notepad window, to see if the white square
changed in brightness, meaning the power supply was sagging. I adjusted the
monitor's Contrast knob as bright as I could before this effect became
visible. Then, I used my cal software to measure the brightness, and used
that as my white luminance for calibration purposes. Of course, you may have
a monitor that you can crank all the way up with no problems. I've never
heard of anyone complaining about a monitor that's too bright, but I suppose
such a thing is possible, in a dark room.

As to black luminance, I like setting it about as low as the monitor will
go, but 0.3 sounds pretty reasonable.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@...

> I use Solux halogens, and have
> tweaked the line voltage with a variac to get 5000K at the viewing surface

Paul - What's a variac?  How much tweaking can be accomplished with it?

A Variac is a big light dimmer. A large variable resistor. They come in 
many different sizes depending upon the amount of electricity used.

As more resistance is applied, the voltage to the lamp drops and the 
light output decreases while the color temp also decreases.

By the use of the dimmer, I assume that the Solux halogens are filtered 
in such a way as to produce light (at normal voltage) of above 5000K.


On Sunday, Dec 19, 2004, at 08:43 US/Pacific, 
DigitalBlackandWhiteThePrint@yahoogroups.com wrote:

> Message: 18
>    Date: Sun, 19 Dec 2004 08:36:04 -0500
>    From: Stephen Petegorsky <petegorsky@...>
> Subject: Re: Setting Monitor Luminance, Col Temp & Gamma
>
>
>> I use Solux halogens, and have
>> tweaked the line voltage with a variac to get 5000K at the viewing 
>> surface
>
> Paul - What's a variac?  How much tweaking can be accomplished with it?

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Stephen 
Petegorsky <petegorsky@e...> wrote:
> 
> > I use Solux halogens, and have
> > tweaked the line voltage with a variac to get 5000K at the 
viewing surface
> 
> Paul - What's a variac?  How much tweaking can be accomplished with 
it?

Running the solexes at the voltage required to get 5000K (about 
13.2V) would reduce life significantly (by more than half)... but 
what I'm interested in knowing is what kind of fixture you are using. 
I am considering building something given the high cost of the retail 
fixtures.

-Pieris

> From: bruce greene [mailto:bagreene@...]
>
> A Variac is a big light dimmer. A large variable resistor. They come in
> many different sizes depending upon the amount of electricity used.
>
> As more resistance is applied, the voltage to the lamp drops and the
> light output decreases while the color temp also decreases.
>
> By the use of the dimmer, I assume that the Solux halogens are filtered
> in such a way as to produce light (at normal voltage) of above 5000K.

Actually, it's a variable transformer, which has a range that allows for
some step-up, not just dimming. Since the fixtures are Chinese, they are
designed for 125V, and the bulbs were running well below 5000K without the
variac.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@...

> From: Pieris Berreitter [mailto:pieris@...]
>
> Running the solexes at the voltage required to get 5000K (about
> 13.2V) would reduce life significantly (by more than half)... but
> what I'm interested in knowing is what kind of fixture you are using.
> I am considering building something given the high cost of the retail
> fixtures.

Some crappy Chinese track lighting, with high-frequency switching
down-converters built into each fixture. I don't have the boxes any more,
but the fixtures themselves say WAC on them, whoever that is. Works fine,
though.

However, you won't get 5000K unless you can step the voltage up a little. I
just happened to have an old variable transformer lying around, so I used
it.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@...

Thanks Paul,

I seem to remember burning out bulbs quickly by applying extra voltage 
to get a little bluer light.

It's been a while since I handled one myself...

-bruce



On Tuesday, Dec 21, 2004, at 07:43 US/Pacific, 
DigitalBlackandWhiteThePrint@yahoogroups.com wrote:

> Message: 8
>    Date: Mon, 20 Dec 2004 20:34:15 -0800
>    From: "Paul D. DeRocco" <pderocco@...>
> Subject: RE: Re: Setting Monitor Luminance, Col Temp & Gamma
>
>> From: bruce greene [mailto:bagreene@...]
>>
>> A Variac is a big light dimmer. A large variable resistor. They come 
>> in
>> many different sizes depending upon the amount of electricity used.
>>
>> As more resistance is applied, the voltage to the lamp drops and the
>> light output decreases while the color temp also decreases.
>>
>> By the use of the dimmer, I assume that the Solux halogens are 
>> filtered
>> in such a way as to produce light (at normal voltage) of above 5000K.
>
> Actually, it's a variable transformer, which has a range that allows 
> for
> some step-up, not just dimming. Since the fixtures are Chinese, they 
> are
> designed for 125V, and the bulbs were running well below 5000K without 
> the
> variac.
>
> --
>
> Ciao,               Paul D. DeRocco
> Paul                mailto:pderocco@...