Digital BW, The Print

Hello Josh,

I've been following this thread, and seems to me there are some
unspoken assumptions going on here that could use some clarification.
so let me add .02 worth.


>>>>
I asked the original question because I have seen on this forum that
many people work in GG2.2 ...   
>>>>

When converting RGB to Grayscale mode (either from a neg scan
or a digicam file), the workspace/image profile doesn't automatically
have to be GG2.2 .  It can default to anything you want.  This is
determined by the Gray setting in the Color Settings window.

There are 7 canned profiles for grayscale images in PS: 2 GG and 5 DG
(Dot Gain) profiles.  You can choose any of these to be the default in
Color Settings (or you can also make your own custom profile and use
that).  Whatever is set there becomes the default grayscale profile
whenever you convert an RGB image to Grayscale (or scan directly into
Grayscale).  After the initial assignment, this profile can be changed
to something else if you wish.  This, of course, doesn't address the
question of which to use and why, but first things first.


>>>>
Another question I have is why greygamma 2.2, and not greygamma 1.8? 
When I bought my first set of piezotones for a 1280, the documentation
from Cone said to use GG1.8.
>>>>

There are lots of reasons for choosing one image profile or another,
but it boils down to what kind of workflow you want to use.  You have
to understand all that stuff before you can make an informed decision
here.  Anyone who is offering advice on how to get started has to say
something.  The PZ folks probably said GG 1.8 because it matched
whatever else they were recommending in the workflow.

I use DG 20% for the image profile because for my workflow it closely
matches the print I get (good WYSIWYG) when the printer driver gamma
is set to 1.8.  I use driver gamma 1.8 because the print density is
closest to what I want before doing any work on the file (gamma 2.2 is
too dark and 1.5 is too light).  If I use driver Gamma 2.2 I have to
do more work to the image to get the print back to the density that
1.8 gives me in the first place.  Why do that?  (there is a more
detailed discussion of this subject in article #4 at the web link
below).

So the bottom line is before you can make an informed choice of image
profile, you must first determine what the output settings will be. 
What they are is largely determined by what kind of over all workflow
is used (BO, partition curves, icc profiles, whatever).  When you add
a RIP to the mix a whole new dimension is added.  I see the image
profile as being at the front end of the workflow, so it seems to me
the best way to determine this is to start at the end and work
backwards.  


>>>>
My real curiosity is that for those of us shooting digital, that start
out in an RGB space, is it useful to convert to a gray space after our
color to b&w conversion, and before continuing the rest of our edits
in PS?  Are there any downsides to staying in RGB?  Possible tints
introduced, file size . . . something else?  I only ask because my
current  workflow includes Photokit Sharpener, which requires an RGB
working space.  
>>>>>

For me the main reason is file size.  Grayscale images are 1/3 the
size (a 90mg RGB file becomes 30 mg).  During the work, when adding
layers, etc., the memory usage is enormous and things take longer, so
grayscale adds an advantage there as well, not just in storage space.
 As for differences in the result, in my early experiments I saw that
prints from RGB images were slightly different in density and
contrast, but with no real advantage either way, just different.   So
I always go Grayscale.  

I hope this is of some help.


Regards,
Clayton


Info on black and white digital printing at    
http://www.cjcom.net/digiprnarts.htm