Re: Pt/Pd printing with various lights

[Judy Seigel <jseigel@panix.com>]

On Thu, 9 May 2002, Sandy King wrote:
>
> I think it is incorrect to describe the reduction in density that I
> reported as solarization. Solarization as I understand it is a gross
> reversal of tones. As I indicated in my first notes the difference
> between maximum density, which took place at about step 6 or 7, and
> the density at step 1, was on the order of log 0.05 to 0.10. I know
> because it was measured with a densitometer but visually you would
> been hard pressed to notice the difference. Carl Weese in an earlier
> message indicated that this was to be expected in Pt/Pd so there does
> not appear to be anything out of the ordinary here.

What is the tipping point -- from "difference" to "gross reversal"? And
if it isn't "solarization", what is it?

For what it's worth, Cassell's defines "solarisation" as, "A term with
many photographic meanings. It is synonymous with reversal (which see),
and it is also applied to halation and bronzing."

for Reversal: "REVERSAL OR SOLARISATION -- A phenomenon occurring as the
result of extreme over-exposure, a positive instead of a negative image
being produced on development. Abney has stated that preliminary exposure
to diffused daylight, the use of a powerful developer, and the treatment
of the plate with a solution of an oxidising agent before exposure,
facilitate reversal; and, in his opinion it can only be produced when
there is atmospheric oxidation. The addition of thiocarbamide to a
well-restrained developer will produce reversal, especially if
hydroquinone or eikonogen is used."

All of which apparently refers to silver chemistry.  Whether or not the
phenomenon in iron chemistry is same, similar, or other, is not (AFAIK) on
record.

Judy