Digital BW, The Print

on 3/21/02 2:28 PM, antonisphoto wrote:

> Todd,
> 
> nicely done and nice of you to take the time to post it with examples etc.

Thanks.
 
> Here is the catch, as I see it, though: You won't see the benefits of the 16
> bits until.... they become obvious!  What I mean is that unless there are
> areas that visibly posterize in an 8bit image as a result of whatever tonal
> moves are done to it, there will be no visible benefit to the 16bit workflow.

Yup.

> For example, if you chose a smooth, grainless sky whose final gray values go
> from 8% to 12% over a large stretch of a big print, you are likely to see
> posterization if you manipulated in 8bits unless the original scan needed no
> adjustment. Grain, or other texture (such as skin in your example) would mask
> this posterization. In that case you have to resort to 16 bits to avoid as
> much of it as possible, and you may still have to add some noise at the end if
> all else fails.

Yup.
 
> So, how about an addition to your treatise: While your conclusions so far are
> valid for the subject and size you have chosen, you may add another example
> where a narrow part of a gray ramp is given the 8 vs 16 bit test and show how
> both histos and visual results compare?

Nope. ;-)

I have no doubt certain images can be broken, and when I expand the article
I'll touch on that, but I can never be exhaustive of all scenarios. I'm not
the only one with the capability to make such tests, so I'm far more
interested in seeing others results than trying to prove anything, other
than that some images can take a lot of abuse, even if others can't. It's
only through testing many different type of images that we can get a feel
for which will be troublesome and which won't, and how far any of them can
be taken.

Todd

> 
> --- In DigitalBlackandWhiteThePrint@y..., Todd Flashner <tflash@e...> wrote:
> It's by no means meant to be exhaustive or conclusive, and I expect it should
> raise more questions than it answers, but it's meant to encourage testing and
> the sharing of results:
> 
>> 
> <http://www.ourwebmaster.com/piezography3000/20020106ToddFlashner1.h tm>