Re: digital negative possibilities for gum
In other words (I hope not to overstate the case but since people are
always misunderstanding me no matter how clear I think I've made
myself, I try to be clearer and clearer) I would feel better if the
comparison I posted yesterday had been done the way I describe below,
not by standardizing the protocol but by optimizing each of the
prints, and then comparing those optimized prints with each other.
On the basis of my previous experience with both types of negatives,
I suspect that what you would see is a similar density range, similar
level of detail, but the print from the bitmap would be grittier, not
as smooth. But I'm not going to do that comparison, because it would
involve constructing a curve for the bitmap, and I'm not willing to
put that kind of effort into bitmaps.
Katharine
On Oct 20, 2006, at 9:49 AM, Katharine Thayer wrote:
On Oct 20, 2006, at 5:44 AM, stwang@bellsouth.net wrote:
And each of these affect how the resulting gum print would look
like. And each will need a different curve and a different way of
printing.
I think this last point is especially well taken, and should
provide a warning against reading too much into comparisons where
the printing method is held constant across different negative
types or conditions.
We think we're making our results more interpretable or
generalizable by holding everything constant, but in many cases
we're doing the opposite. For example, I've been puzzled in the
past by demonstrations that compare the DMax or contrast for
different concentrations of dichromate, keeping the exposure time
and development time constant. Of course, if you're going to go
that, you can show anything you want by choosing an exposure time
that favors the conclusion you want to draw. But the only
reasonable and meaningful way to compare the contrast and DMax of
different concentrations of dichromate, is to print each
concentration at its natural exposure time, which will be different
for each dichromate concentration (since speed varies directly with
concentration) and compare the contrast and DMax of the resulting
prints that are properly printed for the dichromate concentration.
By the same token, if you compare different negative types using
the protocol for one negative type as a standard protocol applied
to all the different negatives, then the negative type whose
protocol you used will of course come out looking best, because
the protocol is calibrated for that material. But it would be
misleading to say that means that material is better just because
it looks better in a side by side comparison of this kind. If
you'd calibrated the protocol on one of the other types of
material, then that's the kind that would come out looking best.
The only way to really compare different negative types in a
meaningful way is to print each using the protocol which optimizes
its performance, which as Sam says will be different for each of
them, and then compare those prints. These *seems* less
standardized, but it's actually more standardized. You're
optimizing the print, rather than standardizing the protocol, and
optimizing the print after all is what we're after, isn't it, or
have we got so obsessed with standardization that we've forgotten
what the goal is? By standardizing the protocol, you're actually
confounding the results, not clarifying them.
Perhaps an example would help clarify my meaning. It's like the
time I printed a small image on a lot of different paper samples,
to use in a demonstration to show how gum looks on different paper
surfaces and textures and so forth. I certainly wasn't going to
calibrate the printing time for 20 different papers (and yes,
different papers do require different methods too) so I just used
the printing time I always used for my standard paper, which at the
time was Arches Aquarelle. But they drew a completely different
conclusion from the demonstration than I intended them to. I just
wanted them to see that different papers give a different look, in
terms of detail and texture, to a gum print. But instead, they
concluded that because the print on Arches was perfect in tonal
scale and contrast and all that, that Arches must be the best paper
to print gum on. I'm not sure I ever managed to convince them,
though I tried very hard, that the print on Arches looked best
because my whole printing protocol was calibrated for Arches, and
that if I had calibrated for a different paper, any of the other
19, then the print on that paper would look best.
Sorry, I'll get off my soapbox now, but this is something that I've
been thinking about for quite a while around different issues.
Katharine
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