Digital BW, The Print

On 3/29/02 7:57 PM, "Martin Wesley" <mwesley250@...> wrote:

> (snip)
> 
>> I think a silver print does have a DyR.  I'm not sure what noise
>> would be in a silver print but I think the minimum perceptible change
>> could be determined -- with some difficulty.  Perhaps it could be
>> done by precisely exposing  and developing greyscale step wedges with
>> veryfine increments in the grey.  If they were in say 1cm squares
>> then the point at which you could no longer tell the difference
>> between the measured densities of the squares would be the smallest
>> discernable change.  No?
> 
> Kevin,
> 
> My reasons for believing this have to do with fact that crystal growth or
> image stain are the result of chemical processes that can be very well
> controlled in a stepless manner at least to the molecular level.
> 
> However, for the moment let's put aside my claim about infinite tones and
> consider that the goal of a nice print would be to convince the eye that it
> is truly continuous so that a subtle gradient in the image such as a sky
> does not have discernable step changes in tone. Would you agree that is
> generally our goal in printing?
> 

Yes, very much so.

> If you cannot perceive the variation that Austin suggests might be the noise
> of a print, then for practical purposes it is zero and the equation no
> longer gives a meaningful result. Austin's equation would only seem to be
> valid for systems that fail to produce prints that convince the eye that
> they are continuous tone.

I agree that if my eyes can only discern 100 shades of grey then certainly I
couldn't tell if the print had 101, 256 or 512 shades of grey.  I think
Austin's use of the noise floor as the minimum increment only comes into
play if the instrument you are measuring with is sufficiently precise.
Certainly, in my view, our eyes as the sensing instrument don't come
anywhere close.  

If a silver print is 'nearly' continuous tone then its DyR is way above that
of the digital print.  It seems reasonable to me that a silver print can
produce more the 256 shades of grey but I don't know for sure.

If we can't perceive the variation, the equations are still valid but the
exercise is largely academic as you suggest.

You could use his definition to compare how close
> they got to mimicking continuous tone. Once you have passed that point and
> are comparing two systems that both convince the eye they are continuous
> tone then his definition does not help you compare them in a meaningful way
> and you are left with the old Dmax minus Dmin.
> 
I agree.  If both systems are producing continuous tones then the need for a
descriptor of that characteristic of the print is moot isn't it?  Part of my
initial reluctance was because to MY eyes many of my prints do appear
continuous tone (I'll grant that many others have a better ability in this
area).  Until you get to that point though it seems that Austin's definition
could communicate the short coming.

One could argue that using terms like 'posterised', and 'compressed tones'
and 'too few tones to render...' could also communicate the short coming.
DyR seemed/seems like a reasonable way to proceed, but not the only way.

> I also want to stress that the comparison of the dynamic range (whatever you
> understand it to be) or the density range of systems is a technical
> comparison and not an artistic one. Photography and especially digital
> photography is so full of technical processes we tend to spend an inordinate
> amount of time on them and often mix them in with considerations that are
> purely artistic.
> 
Absolutely!!  Shortly after I started photography I became obsessed with the
zone system.  I spent hours and hours taking pictures of grey cards and
towels, and changing development times and crapping around in the dark.
While I certainly gained a lot of experience and info it seems to me that I
wasted a lot of time I could have devoted to composition and creativity.  I
have never enjoyed photography more than when I started focusing on the
creative side.  Not only that but two of my favorite prints have nowhere
near a full tonal range.  So go figure ;)

However the time that you and Austin have invested in this discussion has
helped produce a framework in my mind that is helpful for me. So thanks!
> Martin
> 
> 
> 
> 
> 
> Please visit the Group Homepage to check the Files, Bookmarks, Polls and other
> resources as they are often being updated. The page is at:
> 
> http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint
> 
> Please follow these basic guidelines:
> - Include your full name with your message.
> - Include the address of your website, if you have one.
> - As threads develop, trim off excess portions of earlier messages to keep
> them short.
> - As the topic of a thread changes remember to change the subject header.
> - Good manners are required at all time. No personal attacks or "flames."
> - Complete your Yahoo profile.
> - Before posting a question, search the message archives and the various
> resources on the homepage.
> 
> 
> 
> 
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> 
> 
>