> I have recently started printing in palladium and have a problem
> that I need some advice on. An ordinary (suitable for silver)
> negative prints nicely but flat, so I have made a contrasty
> negative at the recommended density of around 2.1 for highlights,
> 1.2 for mid-tones. If I expose this negative for an adequate time
> to get some detail in the highlights I grossly overexpose the
> shadows. I get what I have heard referred to as "bronzing". Can
> anyone suggest a way to avoid this??
>
> Also. I have tried mixing palladium 50/50 with platinum, and I do
> not see any difference between this and pure palladium. The color,
> D-max and tonal range appear to be the same. I developed the images
> in fresh ammonia citrate to insure that palladium deposits wouldnt
> influence the color. What should I expect??
>
> Al Strauss
Others have already responded to Al's questions but I'll add my $0.02
worth anyhow.
1. NEGATIVE DENSITY RANGE
My tests with palladium on a variety of papers show a range of
exposure scale (without the use of chlorate or dichromate) of about
1.6 for the contrastiest paper to about 2.1 for the least. Most
papers cluster around 1.8. This was determined using a 21-step wedge
as the test negative. Unfortunately real life negatives are seldom
easy to read with a densitometer (at least mine aren't). For example,
a typical negative developed to a DR of 1.6 would most likely produce
densitometer readings of about 1.7(hi) - 0.5(lo) = 1.2(DR). However
it would print as if it were 1.5 or 1.6. My negatives have been very
consistent in this way.
2. IMAGE COLOR
I have always found a clear distinction among platinum,
platinum/palladium, and palladium along a scale from cooler to warmer
(also more to less graininess). Even a 1:20 ratio of platinum to
palladium is cooler than pure palladium in my own experience.
Potassium Oxalate produces warmer image color than Ammonium Citrate.
Higher developer temperature also produces a warmer image.
Maybe after working with the process for a while these rather subtle
differences will become more obvious to you - they did for me {:-}
3. SOLARIZATION
Only a problem with pure palladium. Sometimes the coated area outside
the negative will begin to lighten leaving the clear negative edge as the
darkest tone. This doesn't bother me personally. If image shadows
start to solarize yiur negative is too contrasty for your coating
mixture - Use less chlorate or dichromate (or peroxide if you use the
method espoused by John Rudiak).
Hope this is of some help,
Keith