Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@y..., antonisphoto@y... wrote:
> --- In DigitalBlackandWhiteThePrint@y..., mwesley250@e... wrote:
> 
> > You are setting a custom curve for grayscale I assume by printing 
out 
> > a step wedge and visually calibrating the screen to match.
> 
> ---Correct

I find that frustrating. Is there an empirical way to do a match? 
Densitometer readings of printed step wedge to curve?

>  But if you 
> > are working in a RGB space even with a channel layer set to mono 
> > would the custom grayscale curve apply?
> 
> ----No. Not while in RGB. It will apply at the moment of transition 
from RGB to 
> gray. You can set up ways to preview, but that's not the issue here.

Do you need to preview or will the on screen view be faithfully 
translated into the new space with profile conversion?

> 
> > Is there enough difference between the channels to provide 
useable 
> > information at the print level?
> 
(snip earlier)
>  
> > 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.
> 
> ----- That's exactly my understanding too. If you have a subtle 
gradation over a 
> long distance - say a clear sky that goes from 11 to 18% percent - 
you are 
> more likely to notice a difference. Even then, nothing a little 
noise couldn't fix. 
> Even 2% noise will fill in a gap-toothed histo.

Thanks for the tip on using noise! 

> 
(snip)

> >Really need to try it from scan to print 
> > both ways and see if there is a detectable benefit.
> 
> ---- It isn't so much about the 3 channels or the histogram as much 
as it is 
> about the distortion introduced in the workflow when working in 
grayscale and 
> have already calibrated to a printed reference by adjusting the 
gray curve (in 
> the color prefs).

Could you clarify the distortion issue for me? Is this distortion 
caused by the manipulation of the smaller set of data, 8 vs 24 bit?

> The minute you change that gray curve for an alternate use, your 
whole 
> dodge-and-burn goes out the window because it was done for that 
specific ink 
> and paper.

Should you have a whole set of Custom curves, one for each paper? 
Could you imbed the specific curve for that image into the file?

> The other benefits are secondary; though, considering Paul's RGB 
workflow, 
> I'd say the whole grayscale thing should stay in RGB.

I am wondering how that would work with my RGB pyro scans where I do 
have a lot of difference on the Blue channel.

Martin