mr.datsun
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In fact b&w film is less sensitive to tungsten light than to daylight. Like Fomapan, it is 80ASA in tungsten light. It has nothing to do with 85 filter.The speed rating of TriX Reversal is not really an issue. Tri-X is panchromatic, afaik. The dual film speed rating is surely to account for cameras which have a tungsten 85a filter built in. The Tri-X cart auto switches it out on my camera. But I'm also exposing manually with a Weston using incident reading and using 32k Bowens light.
Yes but currently your film is too dark, so you want to reduce density somehow, possibly with with silver halide solvents.*With what you explained to me and now I've read the document 'A Black&White Reversal Process In Memory Of Agfa Scala 200x' I think I'm much clearer on the silver solvent question. It's more important with low speed films. I think with a fast film like Tri-X and it's thin emulsion it only serves to make the whole image too weak at 1st dev stage.
'The amount of silver solvent needed depends on the amount of silver halide in the film and the strength of first development. In principle, lower speed films contain a higher amount of silver halide; they are more capable to build maximum densitiy in the negative. A lower amount of developer concentrate in the first developer creates a softer negative image and leaves more unused silver halide requiring more silver solvent and vice versa.'
In fact b&w film is less sensitive to tungsten light than to daylight. Like Fomapan, it is 80ASA in tungsten light. It has nothing to do with 85 filter.
Yes but currently your film is too dark, so you want to reduce density somehow, possibly with with silver halide solvents.
I'm looking forward to your tests with Adox PanX !!
I think negative behaves the same as reversal with tungsten light and daylight except the difference isn't that noticeable since negative is very forgiving. For example the sensitivity of Efke emulsions was for tungsten light, and not daylight : you had to underexpose by one stop in daylight. I didn't know it at the time when I used some but I have great prints from it. The negatives are bullet proof though, especially in scenes under bright sun...
Film speeds are different for different light sources INDEPENDENT of the filters. That 160 has nothing to do with what the camera built-in filter does. It looks like you're getting over 100 asa with 12 minutes. Even at 100--100 ASA is pretty close to 160 -- this is only 2/3 of a stop "loss" and may very well be within experimental error for meter/shutter/other things. Seems to me it's working just fine. Have you compared to lab results to be sure of your exposure? If you pick up this experiment anytime, it may be best to first do a baseline with lab results so you can see what the "best" is to expect with your equipment. I think I get over a one stop "drift" among my different 35mm cameras when doing e-6 film. Each camera must use a different film speed to get the same results because of different meters, lens transmissions, shutter speeds, other things I can't account for.
Lab to compare with will give apples to apples, as it were. Right now you're comparing to an unknown and maybe unrealistic standard.
Sorry to hear you're packing it in....
johnielvis,
Even though it did not seem to suit Tri-X specifically, I'm not sure why you say hypo should be avoided though, as even Kodak put it in their d94a. It's also what what i can see in every reversal recipe in the literature.
Like I said before--those formulae are for tightly controlled machines--VERY SHORT processing times...a couple of minutes max. In my experience, I could never get the silver solvent in the developer to work reliably. Maybe you can, but I've stopped trying (at least until I get or build a film processing machine)--right now I'm doing hand processing/tubes. So for my processing methods, I've found silver solvent in developer is not a sufficiently repeatable process for me. I have found that when I screw up exposure and get a transparency that is "too dark", that I can fix it with ferricyanide bleach (if it isn't too bad). I go for "old reliable" methods that you can not do for a couple of months and start right in and process without screwing up because you're "out of practice". This IS a hobby for me, after all....
Actually--it's more of a laziness thing, come to think of it. I've found that hypo in the developer is not necessary for me to do satisfactory reversal processing. Since it's not necessary, I'm not about to complicate things and add in steps (time, extra work) to my process--each step (measuring, adding another chemical) is also an opportunity for error. So it's a combination of laziness and desire for a very, very robust process with as much "slop" in it as possible. I do admire precision, but precision where it is not necessary is a waste of resources (laziness).
OH...if you want to experiment with the hypo in developer, there is a small book I HIGHLY RECOMMEND called "The Monobath Manual"...it's a VERY good read and will show you the effects of hypo and what to expect in such processes.
I'd pay attention to what PE one said on Apug.org about the neccessity of using a silver halide solvent. He's very expert at anything that is chemical related!
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