How sensitive are films going to become to things other than light?

[Photo Engineer]

The 24,000 ISO film is normal 400 speed film with 2 addenda. It yields a positive image with the grain and sharpness of the 400 speed parent emulsion. This speed jump takes place with any emulsion, but the final speed is based on the original emulsion.

Direct positives can be made with converted emulsions and the use of a nucleating agent to give quite high speed, but grainy, images. However, due to internal fog, any silver halide solvent will cause fog, and any overexposure will cause re-reversal. Many commercial products used these. They ultimately vanished due to various problems.

Normal films developed in the presence of a catalytic agent and color forming materials will experience a huge speed gain with normal grain and sharpness but will have an increase in contrast to some extent, depending on silver level. Usable latitude will decrease and move towards the toe.

There are many many such processes and tricks in formulation to change films in speed. If they are too hard to process or too hard to manufacture, or the market is too small, they vanish or sometimes, never even come to fruition.

PE

 

[Kirk Keyes]

Fallout fogging paper
In the mid 60’s I was working in a photofinishing plant in Canton Ohio.

Probably 1962 or sooner. The last US above ground test was in 1962 with the Limited Test Ban Treaty of 1963 ending that.

 

[Gigabitfilm]

You can construct only that, you have understand. I remember very well the lesson, Mr J. W. Mitchell hold in Cologne 1986 about developing AgHal in a gelatine matrix and the disturbing in the moment of beginning. The other is the correct coating of an emulsion. Old greecs would say – Scylla and Charybdis.

From the 6 stops speed, you described, 2 stops (or 2 1/2?) I had made with my efforts, that means, the contrast effect, you described, would be probably not so high (or not) in a fog incorporating developer.

Your reflections about the different trials to get the full speed will animate me, to look further. I have now noticed, that in my concept of a fog incorporating developer could be a possible potential for „mounting/generate“ the „catalyst/level“ for real speed. I would carry this responsibility for that, in the limits of an independent one-man-show as I act until now.

 

[Gigabitfilm]

The first simple test, shipping between Scylla and Charybdis, looks interesting, 2/3 stop more on this GTP (chemistry HDR Version I +testad1, 1+10, 28 C, 4 Min), latitude and anything else stays correct, no Mackies, only with one classic substance from this class, but huge.

In my archiv I remember an article long ago in a newspaper for engineers (VDI-Nachrichten?) about this 25K-ISO film, and a news from the Paris salon for photo and cinema in around 1980?, where a (US-?) Company KEM presented additives for E6, C41 and bw, every additiv enhancing speed around 2-3 stops (from my memory, with no guarantee). I have the feeling, to re-invent parts of this new. Why it was forgotten??

 

[AgX]

PE, Gigabitfilm,

Both of you unfolded roadmaps to 25k ASA. However both of you were so negligent not hand us the thread of Ariadne to find our way in that labyrinthic roadsystem of potions and nuclei.

By the way, my roadmap, or rather sketch, to 25k is the Solubilization by Incipient Development. (Which is a high-efficiency variant on the classical Diffusion Transfer Reversal, however with some addenda to encapsule the halides to control solubility. Well, some potion…)


Off topic:
Gigabitfilm, you wrote “once existed a film by Agfa from RANZ – Agfacontour”.
To my understanding this film was created by Edith Weyde, though I only found the Ranz et.al. patent. Anyway, a concept of intellectual beauty…

 

[Photo Engineer]

AgX;

The patent is issued to Eastman Kodak and the inventors include Paul Gilman and Don Black.

The thread here with more information should be easily found by a search for it.

PE