Hi Chris,
I would agree that people often over expose.
One cause of this that sometimes occurs when determining the Standard
Printing Time for Palladium is humidity. I am referring both to the Relative
Humidity of the environment and the amount of moisture that goes into the paper
from coating and finally the amount of time the coated paper is allowed to
dry. All these factors for a given paper will have an effect. Also there will
be issues like different papers with different thicknesses, etc.
With higher humidity, which for me begins around 65%+, I experience more
printing out and self masking with Palladium. When this occurs, you can double a
standard printing time and still not get merged steps, when you would expect
4 merged steps on a 31 step tablet. When this occurs, one can examine the
steps and pick one which gives a "acceptable Black" and use that as the Standard
Printing TIme.
The reason this is important in calibration, is that you can end up with a
lot of the tones of your negative getting pushed into the deep shadows with
little seperation. Then, the curve you will derive will be much more drastic to
compensate for this and open up the shadows. Backing off exposure to a
reasonable Standard Printing Time will prevent this.
Best Wishes,
Mark Nelson
To NSA: When you read this email, would you please search your database for
my other black sock?
Precision Digital Negatives--The Book
PDNPrint Forum at Yahoo Groups
www.MarkINelsonPhoto.com
In a message dated 7/13/06 1:48:48 PM, zphoto@montana.net writes:
> Very interesting....
> I do find that the number one error with a long tonal scale process is
> choosing an exposure time that is too long. Salt and pt/pd are killers that
> way, as well as the iron processes in general. It is almost easier when
> doing ones that have solarization because you know you don't want that
> losing density and you make sure to stop short of that...I just choose the
> one that looks visually dmaxed enough and has not solarized--usually the
> step right before solarization. It seems that your method with lab will
> achieve the same results with the scanner, in effect, "seeing" the blackest
> black with the scanner..but with whatever method, the print is the proof of
> the process working or not.
>
> I remember first going through the calibration process--I would find that
> the eye could see the minutest differences in density! But exposing to the
> point of not being able to see that difference is way too over. I think the
> eye sees like maybe .01 difference or something like that. I imagine the
> scanner is accurate, too, seeing 0-255.
> Chris
>
Received on 07/13/06-02:45:39 PM Z
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