Digital BW, The Print

----- Original Message -----
From: "Todd Flashner" <tflash@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Thursday, March 28, 2002 12:35 PM
Subject: Re: [Digital BW] Dynamic Range Definitions and Print Tones


> on 3/28/02 1:22 PM, Martin Wesley wrote:
>
> > For my
> > work I couldn't live with just 256 shades of gray and would still be
> > sloshing around in the dark.
>
> Hmm. Next time you're working a grayscale image on your computer change
your
> monitor from millions of colors to 256 shades of gray and tell me if your
> image looks any worse for wear.

Todd,

I tried it and the on screen image looks terribly degraded and posterized in
comparison to 32-bit color monitor setting.

> And unless you are printing from images will
> full histograms, end to end, I'd presume your images to have less than 256
> shades of gray.

I have done some mono-ink prints and I am guessing that with dither they
probably give you something beyond 256 shades. They are very good for my
TMax 400 35mm negs but I am not happy with this for my 6x7 or 4x5.
>
> I suppose one could create a white to black gradient in Photoshop, and
> posterize it into as many steps as they want, print it, and see how many
> steps they can distinguish. I'd bet somewhere beyond 100 or so either the
> printing system or our perception would begin to break down. However, any
> system that can reproduce Tyler's Zees successfully can handle the 100
tones
> that comprise it, so we know at least that much IS possible today.

I really wish I had some comfort level as to how many shades of gray can be
perceived by the human eye or at least a range since there is bound to be
person to person variation. I have heard 100, 256 up to 1030. The most
thorough study which I neglected to save was done in Sweden and they
reported that most people could differentiate between 800 and 900 shades of
gray but that artists and people in the graphics industry could see 900 to
the 1030 number. Unfortunately they did give any details of how the testing
was done. I hate newspaper articles about scientific tests.

I think that if it is some fixed number of say 256 you can have multiple
sets of 256 tones in an image that contribute to its impact. Say you could
only differentiate 256 but you had 1024 tones. Your eye could see the
difference between 1 and 4, 4 and 8, 8 and 12, etc. You could also
distinguish between 2 and 5, 5 and 9, 9 and 13, etc.

Martin