I was going over Anchell/Troop to read up on speed increasing additives and I came across a piece on using h202 to "steam" film to get a speed increase. I've never done this (surprised I haven't, actually) and am looking to try it out.
Has anyone experience with doing this? Output from negatives "steamed" in this way?
Thanks!
And that seems to be the main problem with these "I gain two stops if I immerse the film in toad liver for two days around full moon" recipes: they won't improve the speed of modern and fast films, where we would like it most.
Believe me, I am a die hard analog user, but when it comes to use of Mercury vs. a d*gital camera I'd go for the latter, regardless of whether Mercury provides a measurable benefit or not.H2O2 and Mercury hypering improved Provia 400X pushed to 1600 results for one user.
I've not done any experiments myself, and from reading countless postings, books and other resources about these procedures I see little reason to do so. Tell me a working recipe that boosts the speed of Delta 3200, Provia 400X or Portra 400 without the use of extremely dangerous chemicals and I'm all over it.What methods have you tried with which modern films and found no effect?
The Anchell books contain quite a few errors so read them cum grano salus.
You use a SS two reel tank with a small amount of 3% hydrogen peroxide in the bottom. An empty reel actrs as a spacer between the film and the peroxide. The film is left for a number of minutes which must be determined by trial and error for each film used. The film must be used shortly after treatment and cannot be stored as it reverts to its normal unsensitized state quickly.
Hypersensitization doesn't increase speed. It decreases reciprocity failure.
It also works best with slow films, like Tech Pan. Hypered Tech Pan is one of the fastest films when it comes to 6 hour exposures. For TP and astro films (TP was originally 'solar flare patrol film' - hence the extended red sensitivity for imaging the hydrogen line, making it beloved of amateur astronomers) there is some modest across the board speed increase, but nothing to write home about - I ordered some hydrogen hypered TP once, maybe it was ASA 40 rather than 25 for normal use.
Hypersensitization won't do anything for you if you are trying to get more speed out of Tri-X.
If I read Anchell correct the H2O2 treadment is done after development, before fixing and not before exposure like some of the other method he covers.
Best regards
If I read Anchell correct the H2O2 treadment is done after development, before fixing and not before exposure like some of the other method he covers.
Best regards
There is a big difference between hypersensitization and latensification. Hypersensitizing a film is done before and latensification is done after exposure. Some authors either equate or confuse the two. The mechanism for the two processes is different. However, the same chemicals hydrogen peroxide, mercury, sulfur dioxide, etc may be involved. For the average photographer the processes are a curiousity and more bother than it is worth. This is why only astronomers use these technoques because they must.
For those who insist on trying hypersenitization the easiest method is exposure to a very dim green light for an extended period of time. The method most often described is the use of a Kodak Brownie safelight with the green cup. A 7 watt bulb is used and half of the cup is covered with black tape. IIRC, the film is exposed at a distance of 8 to 10 feet for a period of several minutes. Afterwards the film is respooled for use. As I mentioned before every film is different and the method must be tweeked for each film.
Ok but that doesn't really matter. the OPQ was about H2O2 steaming which is done after development, before fixing and, as you would put it, is a latensification method.
Best regards
The question remains whether any of these methods improve film speed for >100 ISO film speed emulsions. All these long threads about green light and H2O2 always end up naming ISO 50 or ISO100 films. If I wanted to boost speed of an emulsion, it would be Delta 3200, but for some reason this film is never mentioned in these threads.
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