Digital BW, The Print

Antonis,

I am not quite following the workflow here so I have inserted some 
questions:

--- In DigitalBlackandWhiteThePrint@y..., antonisphoto@y... wrote:
(sniP)
> 
> Here now is a workflow idea (8 or 16bits)  that I would like to 
post for
> feedback and comments:  
> 
> -The scan of the negative or other monochrome original is done in 
RGB (8 or 
> 16) and  saved out of the scanner software with the appropriate 
profile. If it is 
> an existing gs file, it can be thrown into RGB mode (with careful 
choices in the 
> gray and RGB color settings).
> 
> - The file is then opened in photoshop for tonal adjustments while 
still in RGB. 
> But  before starting, we check our color settings (the following 
assumes PS 6): 
> a)----Under gray we have created a curve that matches the 
paper/ink/printer 
> we intend to use. That means that a _grayscale file_ on screen will 
look 
> identical to a print made under those settings. 
> b)----Under RGB we set the same color space that the file came 
from, so that 
> the intentions of the scanner and our view in PS match. The only 
real critical 
> number here is the gamma.

You are setting a custom curve for grayscale I assume by printing out 
a step wedge and visually calibrating the screen to match. But if you 
are working in a RGB space even with a channel layer set to mono 
would the custom grayscale curve apply?

> 
> - We now do global and local adjustments as needed while still in 
RGB mode. 
>  At this point we have the option to add a channel mixer set to 
mono as the top 
> layer (if in 8bits) which does 2 things: Helps us see a consistent 
gray-color 
> image, and allows us to pick whatever mix of scanner channels looks 
best 
> (more important for CCD users).

Is there enough difference between the channels to provide useable 
information at the print level?

As a thought, what if you modified the gamma of each channel slightly 
to increase the difference between them?
> 
> - After we are happy with the look of the image, we make a dupe of 
the file, 
> flatten (if it was 8bits) and convert to grayscale. We now notice 
that the file
> looks exactly the same in grayscale as it did in RGB. What in fact 
has 
> happened is that Photoshop has internally "adapted" the RGB file to 
the Gray 
> settings we previously set, which compensated for our 
paper/ink/printer. It is 
> like putting it through a custom profile made for our specific 
output.

Okay so this is the answer to my first question. In the mode change 
Photoshop is also performing a conversion from one profile to another.

> 
> - We now take that grayscale and print with no further adjustments.
> 
> There may be several benefits to this:
> 
> -We have a master file in RGB from which subsequent gray files can 
be made 
> for different papers just as one would for color (through 
profiles). 
> - We have used all the information our scanner is capable of by 
utilizing all
> its channels with whatever benefits they each may have in noise, 
sharpness 
> etc.
> - We have done no moves in the fragile 8bit gray mode. We stand a 
chance at 
> a better histogram (depending on whether we move all 3 channels at 
once or 
> separately).

I am beginning to wonder if the 8-bit space is as fragile as we have 
been thinking. After doing some identical manipulations of raw scans 
at 16 and 8 bit to the point of heavy combing of the 8-bit histogram 
I am not seeing any difference in the print quality. Not to say that 
there would not be a difference at some point but a bad 8-bit 
histogram does not automatically mean a bad print. It may mean you 
are getting close to the edge of posterizing but that edge may be 
image dependent.

Todd should jump in here as he has been giving me these terrible 
ideas.

> 
> That's the general idea: work in RGB, drop to a pre-calibrated gray 
when done 
> and print with no other tweaks. This may help with the situation 
Todd was 
> describing - but is also a good workflow that allows quick 
alternate files for 
> different print settings without re-curving each file.

The theory is sound but I don't know how much you are really getting 
in print quality at the end because of the very close similarity 
between the three channels to start with. You are also paying a 
performance price in working with the bigger files.

My feeling is that for a normal negative requiring moderate 
adjustment there might be no gain but for manipulating a difficult or 
marginal negative perhaps. Really need to try it from scan to print 
both ways and see if there is a detectable benefit.

Martin
> 
> I hope we can compare notes on the above.
> 
> Antonis Ricos