Step Tablet Pedometer
 

I've been testing print developers using a step tablet. Two questions:
Where should I start counting? and at the end points of density how
much of an edge or step is needed to count as such? I'm reluctant
to count barely discernible edges or steps. I wish to be a good
pedometer. Dan

Step Tablet Pedometer
 

Dan Quinn wrote:
I've been testing print developers using a step tablet. Two questions:
Where should I start counting? and at the end points of density how
much of an edge or step is needed to count as such? I'm reluctant
to count barely discernible edges or steps. I wish to be a good
pedometer. Dan

I stick the wedge in the enlarger and make any old exposure, say what I
normally use for average prints. When I do this, I find that the less
dense steps are either all the same dense black, or they are not: that's
tautology for you. If they are all the same, your exposure is too much.
If they are a poor black, the exposure is not enough. It is usually
fairly easy to make a few runs until you get the clear step to print
maximum black, and you count steps to notice what range negative you
need to print on the paper at hand.

When I first did that, it was very interesting. I had thought that the
step with about 0.75 density should print Zone V under those conditions,
but it was always too dark, about Zone IV. Without thinking about it, I
just developed negatives N+1 and Zone V came out all right, but the
contrast was too high.

My solution was to develop normally, but expose the film so a Zone V
subject came out to a negative density of about 0.9. This puts Zone I at
a density closer to 0.3 than to the 0.1 typically sought. I.e., using
the film at about half the EI I used to use. This permits very dense
blacks to be obtained from the paper, Remember if the clear step is not
giving maximum black, nothing else on the negative will either. Of
course you need more exposure at printing time as well as when you
expose the negatives. But it works well for me.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ Registered Machine 73926.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 7:05am up 2 days, 18:04, 2 users, load average: 2.36, 3.28, 3.65

Step Tablet Pedometer
 

"Dan Quinn" wrote in message
om...
I've been testing print developers using a step tablet.
Two questions:
Where should I start counting? and at the end points of
density how
much of an edge or step is needed to count as such? I'm
reluctant
to count barely discernible edges or steps. I wish to be a
good
pedometer.
Dan


I think the confusion comes from visual judgement instead
of using some sort of densitometer. The barely discernable
steps at both ends are the toe (dark end) and shoulder
(light end) of the scale. With a reflection densitometer you
can plot the actual values and see what the paper is doing
quantitatively. If you don't have the instrument then visual
judgement will have to do but I think you can tell a lot
from it.
First, your eye is _very_ good at judging the difference
between adjacent areas of differing brightness but awul at
judging differences which are separated. Since the step
tablet probably has a considerably wider range than the
paper the exact exposure will not matter too much. You can
make test strips from the tablet using different
combinations of exposure and development or developers and
compare them by laying one next to the other. The number of
steps and their distribution should help in judging the
relative contrast and curve shape. To judge absolute maximum
density you must look through the paper with transmitted
light. Most printing paper will generate a black to dense to
be told from a slightly less dense one by reflected light.
Transmitted light lowers the effective density of all steps
since the light goes through the emulsion only once. For
normal viewing it goes through twice. You may be able to
adapt a sensitive light meter to read the transmitted
densities. While the paper surface and texture affect visual
conrast and density you can still get a good idea of what
changes are happening due to the variations. Of course, a
transmission densitometer can also be used this way if you
happen to have one.


--
---
Richard Knoppow
Los Angeles, CA, USA

Step Tablet Pedometer
 

Jean-David Beyer wrote

Dan Quinn wrote:
I've been testing print developers using a step tablet. Two questions:
Where should I start counting? and at the end points of density how
much of an edge or step is needed to count as such? I'm reluctant
to count barely discernible edges or steps. I wish to be a good
pedometer. Dan

I stick the wedge in the enlarger and make any old exposure, say what I
normally use for average prints. When I do this, I find that the less
dense steps are either all the same dense black, or they are not: that's
tautology for you. If they are all the same, your exposure is too much.
If they are a poor black, the exposure is not enough.

It is usually
fairly easy to make a few runs until you get the clear step to print
maximum black, and you count steps to notice what range negative you
need to print on the paper at hand.

"...the clear step to print maximum black" The clear step is step one.
I'll pay more attention to that. I've not been making a point of it. I
think that will help.
For paper contrast estimates I've not been counting the max. black or
the paper white. I've not found while reading 'THE' correct counting
method. D. Vestal suggests reading the edges.
I print only step one through eleven. Using 5x7 paper, both ends are
exposed by turning 180* in the easel. Dan





When I first did that, it was very interesting. I had thought that the
step with about 0.75 density should print Zone V under those conditions,
but it was always too dark, about Zone IV. Without thinking about it, I
just developed negatives N+1 and Zone V came out all right, but the
contrast was too high.

My solution was to develop normally, but expose the film so a Zone V
subject came out to a negative density of about 0.9. This puts Zone I at
a density closer to 0.3 than to the 0.1 typically sought. I.e., using
the film at about half the EI I used to use. This permits very dense
blacks to be obtained from the paper, Remember if the clear step is not
giving maximum black, nothing else on the negative will either. Of
course you need more exposure at printing time as well as when you
expose the negatives. But it works well for me.