Digital BW, The Print

on 5/22/02 9:41 AM, Austin Franklin wrote:

> But, they are specifically talking about color, and for color, what Dan says
> (as well as others, including my self) is correct, but that is only for
> color.  With 8 bit color you have 24 bits, not 8.  With grayscale you have 8
> bits, and that's it.  It's an entirely different matter.


Okay Austin, It seems you are correct. Below was part of Dan's recent post,
and as you said, he does indeed specify "color":

"I therefore issued a challenge for those who could come up with any color
photographic image where any reasonable course of events might conceivably
show an advantage for working in 16-bit as opposed to just converting
immediately to 8-bit, and said if I could verify it I would admit it and
print the results."

But how 'bout showing us some of your posterized images for our edification?
It's most interesting when the same moves are made to a duplicate 8-bit and
16-bit file and the two are compared. If you remember my little article on
the topic 
(<http://www.ourwebmaster.com/piezography3000/20020106ToddFlashner1.htm>),
which did use a BW image, fairly substantial moves can be made before
deterioration shows. Remember, we only need to retain a max of about 100
tones for a BW print; which means we can lose 156 out of 256. That's a lot
of admissible loss. The other thing is, even IF the 16-bit image looks
different than the 8-bit, does it look better?

I believe if/when this debate actually includes images the understanding of
the perceptual forces at work will be very interesting, which is why I'm
such a prod to get people to participate. It's not just if tones get lost,
it's how many, and where in the image, and what type of image.

Todd