DI, developer incorporated emulsions came up
on an other subject thread. I thought it a good
subject to be up front.
I reviewed an article by Steve Anchell in Camera & Darkroom
where he mentions the addition of a small amount of standard
paper developer to the emulsion. Speed AND Contrast can be
increased by doing so. He was working with Liquid Light.
In my quest for whole-print contrast control techniques I
did not ignore the mentioned Contrast Control. Steve added
a little Selectol Soft but did not go into any detail at all
save for mentioning a shortened emulsion life. Note,
Selectol includes an activator.
Such a simple approach; a pre-soak in a very dilute
developer, dry, then expose. There may be some very
interesting experimenting! Has anyone tried the method
on any usual print paper? Dan
Originally Posted by dancqu
Dan, most papers sold today contain small amounts of incorporated developing agents.
To test for this, add a drop of sodium hydroxide solution to the paper in the light. If it darkens or turns black, it contains an incorporated developing agent. If it does not, then there are no incorporated developing agents.
This is not the traditional method of controlling contrast. Contrast has usually been controlled by metal salts, gelatin type, pH, and organic antifoggants.
The keeping of these newer emulsions with developer incorporated is shortened, and cannot be improved much by refrigeration, as the decomposition is through aerial oxidation.
I thought I should confirm Freestyles claim of DI
Originally Posted by Photo Engineer
free Graded papers so I tested an Arista Gr.2 RC
with Na2CO3. Zero indication. Perhaps the agent
involved was not or was so little activated by a
carbonate as not to show. Perhaps very minute
amounts, none even, are present. So the
So, from my reading of S. Anchell I'd suppose
speed enhancement is the reason for the small
amount of DI. If not for altering the contrast
what other than altering the speed? Dan
Dan, try using sodium hydroxide (NaOH) instead. Sodium carbonate works, but it needs to be in concentrated amounts.