I wrote a beautifully crafted reply to this posting but the computer told me
that there was a a stacking error and closed the file.
But thank you for your carefully considered, objective and enlightening reply.
Peter Marshall has commented in similar terms and thank you too, Peter..
"On Fri, 7 Jun 96, David Beakman wrote: <Therefore, it doesn't matter what the
final Dmax of the paper is, what really matters is what range of negative
density can the paper accept.>
Correct only, as long as you don't compare apples and oranges (sensitometry and
perception.) Certainly every process needs *his* negative. And a Dmax 2.0 paper
will show more different tones than a 1.4 one. "
Is it not possible that if our perception of d max is different from the
sensitometer's mechanical record, that our perception of intermediate tones
might also be different such that we may be able to perceive as many tones in
1.4 on platinum as we can in 2.0 on silver gelatine.
". That platinum
needs a dD of 1.8 and a silver print 1.2 doesn't mean, that there are more tones
in the platinum. In fact there will be less tones perceivable due to the lower
Dmax. Or, as Peter Marshall pointed out: <The number of tones you get is largely
a function of the density range of the print medium (with some allowance for its
surface, the illumination you use to view it etc.)>"
But does that necessarily follow in terms of perception. You say yourself that
we should not compare apples with oranges.
"But, as was said already, the total amount of different tones is only worth
discussing for "density transmitters" and not necessarily for artists..."
And so say all of us !
"Pete Marshal wrote: <For what it is worth I don't feel that platinum gives an
apparently denser black than some silver materials (although carbon does.) All
these materials can give an adequate black which is what really matters.>
That's it. It must be adequate, no matter what number hides behind its Dmax."
Again this is a matter of perception. To me platinum looks as black as a carbon
made with mat black pigment but I know that I can get more tones from a gravure
although I am about to try engraving ink to see if I can emulate the
platinum/carbon black with gravure.
To summarise in words of few syllables :
1. A silver gelatine negative can record the brightness range of a scene beyond
a range of eight or nine stops.
2. The negative from that exposure can be overdeveloped to produce a negative of
a wide density range for printing onto papers where the sensitiser is in the
fibers of the paper so that the self masking leads to an acceptance of a very
wide density range.
3. The negative could also be developed in a low contrast developer ( pyro soda
? ) to print onto normal silver gelatine paper.( May there not be problems with
the d log H slope here ?)
4. The higher density range negative could also be printed onto very soft silver
gelatine paper.
5. With dodging and burning in on the print or on inter negatives and positives
it is also possible to print detail on the negative not perceptible to the
observer at the time of exposure on both s/g and pt/pd papers.
On Fri, 7 Jun 96, Terry wrote:
<The question I have been asking is how wide a brightness range can we perceive
if we are at a single point and do not move from it. No matter how much we scan,
if an area is on zone 9 and the area next to it is on zone 1 and we are looking
at them both at the same time we will not be able to see the detail in zone 1
although both can be recorded on film> A day later you say: <I say that a scene,
at one time from one point, can recorded on film with the film recording far
more than we can see because we do not have the opportunity for the eye to scan
and adjust and we are not physically capable of perceiving contiguous
brightnesses that differ by more than about seven stops.>
"Terry, are you crosse-eyed? How can you look at two details at the same time?
As
soon as you are switching from one to the next detail (scanning...), your eyes
adapt to its brightness and the longer you concentrate on it, the more details
you perceive. Only if your eyes rest on that single detail, your point is
correct:"
Klaus, I am not crossed eyed neither am I related to the eminent Dr Strabismus
of Utrecht. This was the point that started this thread. Do you ever mask off
the light to look at a negative or a transparency on a light box. I am sure you
do. You also know that if you did not your ability to see the darker
transparency against the light would be reduced and the the longer you looked
so the ability to scan would be reduced by the high contrast. The same principle
applies when looking through the camera. It is not just a matter of points but
of broad areas that are contiguous to each other. This is not just a matter of
my perception. I asked my companion, on the day when the point first started to
worry me, whether his perception was the same. It was.
" Then high or low densities in the neighbourhood will disappear in
brightness or darkness. And certainly you are right considering that as the
interesting point: Our decision what to show and how to show it. I assume that's
what you mean when you say:
< That is just one of the points. If the printer is presenting more than we can
see of the scene, the printer is imposing his own view of the syntax on the
viewer, and it is a distortion.>
No, it is not a distortion, it is just a physically correct "density
transmission" but probably not an interesting "density interpretation" (which
would be distortion in a positive sense). "
It may not be a distortion in terms of the machine but it is in terms of human
perception which, you agree, differs.
<The real point remains that platinum can accept more of the scene, as we see
it, directly from the negative than can the silver gelatine print.>
Certainly
wrong regarding physics, but definitely true as an artists statement. "
I accept that.
I enjoyed this discussion, which (at least to me;-)) clarified things.
And to me. Thank you Peter and thank you Klaus.
Would
those who took part in it agree to the consensus: "Sensitometry is a perfect
tool but not the key...?"
Yes.
Klaus make you way to a brightly lit interior of an old church on a summer
Sunday afternoon. See if you can see the detail in the shadows if you are
looking at sun lit whitewashed walls at the same time. And so as to make best
use of the occasion, say a prayer for us all too.
Terry
p.s.: Judy asked: <Just one other point: what's "the original scene" got to do
with it?> A too philosophical question for me... ;-)