Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Joe Dempsey"
<jdempsey@c...> wrote:
> Nelson:
> The gamma setting for Windows is 2.2, for Mac 1.8 ... at least
that's what
> two genuine PS gurus have told me.

Joe, sorry but that's an old rule that doesn't really apply any more.
Photoshop corrects for whatever gamma the space the file resides
within then to the gamma of the monior profile. You could easily
reprofile your monitor to a different gamma setting, and assuming both
profiles were good, the file would display the same in Photoshop.
Many of us Mac people profile our monitors to 2.2 now, so files will
display the same with non-icc aware apps like browsers.
At any rate, the gamma decision for Photoshop spaces is not a platform
issue.

> When converting to BW, direct to
> grayscale is the worst option because it considers converts colors
to gray
> equally.

Not meaning to beat up on you, but that's not true either. I believe
it's a 30/59/11channel mix.

>...LEAVE BRIGHTNESS AND CONTRAST
> ALONE, THESE ARE DESTRUCTIVE ADJUSTMENTS ... levels and curves are
> non-destructive adjustments.

Sorry again. All of these edits are destructive. Brightness and
contrast are generally not advised as they will probably clip without
your knowledge. With levels and curves at least you have a handle on
that yourself.
Gotta watch them gurus like a hawk.

As far as an ideal gray space for QTR output, a quick experiment shows
that a custom dot gain space of 31% (put 81 in the 50 box) makes 50%
gray equal to a LAB value of 50.
2.2 gamma is pretty close also, L50=52% in gamma 2.2.
Whether or not that means those spaces on monitor will closely match
QTR output on paper would have to be tested.
If you are doing RGB to gray conversions, there's something to be said
for using spaces of equal gamma. AdobeRGB and gray 2.2 or ColorMatch
and gray 1.8.
If you have plenty of high bit info in your files these concerns are a
bit less.

 Tyler