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....
Thanks for clearing that one up. I was confused.
Originally Posted by Tofek
Thanks - I'm clear on the film rating issue now.
Originally Posted by johnielvis
Yes, a lab processed Tri-X might be good idea as a benchmark.
I've got 4 carts of Tri-X in the fridge - so i'm not really saying goodbye, Tri-X, so much as 'Au revoir Tri-X and bon matin, Pan-X'.
The change might shed some new light on my processing.
I got to the storage area and found the olde reversal process book photocopies. The process for Kodak d-94 reversal first developer is 1.5 minutes at 72 degrees F. This developer is very powerful and has hypo in it as well as sodium sulfite for silver solvants.
Home processing done at such a fast speed, with filling/emptying will surely mess up any uniformity in the process. This is a powerful developer that goes in and WHAM hits that film like a hammer and then gets out quickly. This likely results in a higher effective speed. What I think is going on here is that the developer gets in and develops the exposed stuff very quickly and aggressively--the unexposed stuff takes time to start developing fog to ruin your dmax. If you use a hotter, stronger developer, it has the effect of getting the development done before the fog can catch up. If you use a weaker developer at colder temperature for a longer time, then the fog can catch up and ruin your dmax. So to get the same dmax with a weaker development, you must sacrifice some speed.
2/3 stop ain't much.
You are going to have to live with the limitations of your processing equipment, I'm afraid.....unless you want to build a special machine. You want to go to the moon, you're not going to do it with junkyard materials...you can maybe build an airplane or balloon though.....
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I don't think that the loss of speed due to fog being developed in the 1st dev. If fog had been created in the 1st dev, it would have been bleached away thus resulting in a brighter image. It's the opposite.
It is rather that all the negative silver isn't developed and thus isn't bleached. There are some silver halides left in the transparent parts because they haven't been developed as negative. The fog is created in the 2nd dev, because too much silver is left in these transparent parts. That's why a silver halide solvent would help to gain speed.
So I went back on my word. I just finished the 16 minute test before I do the Pan-X. Just to call it a wrap.
Tri-X Reversal. D19 1+0 , 16 minutes 1st / 8 minutes 2nd.
Here's the news. Nothing to be gained between 12 and 16 minutes. 100 ASA is still the best result but probably not as good as 12. More contrast and tones crunched.
But then there was only little improvement/difference to the 100ASA exposure between 8 mins and 12 mins so I was kind of expecting it.
200ASA more usable but the bottom 3 zones are more or less combined flat black.
I'll post the scans next week.
Last edited by mr.datsun; 03-16-2013 at 03:36 PM. Click to view previous post history.
I think I might try johnielvis' suggestion of the weaker solution when I get the time. I reckon take the 8min version as a plateau and run it diluted at 1+1 for 16m.
In the meantime Pan-X tests have started and are moving into the silver solvent stage next. I feel happier having two emulsions under test as one is more likely to yield results and that will take me into production sooner.
Last edited by mr.datsun; 03-17-2013 at 07:34 AM. Click to view previous post history.
I think I said before that anything past 10 minutes is not worth doing since the fog starts to develop. I was hoping you'd try 10 minutes at a higher temperature like 75 degrees, say? Instead of cold at higher time. It appears to me that the increased temperature gets more WHAM at the beginning. It's like you CAN'T make up for less active developer by developing for longer times--there's a certain activity level you need.
Before you go with the solvants, there's D-11 and D-8 developers also--much stronger than d-19. You can also goose d-19 by adding more carbonate or caustic soda to make it more powerful--or use it at a hotter temperature. Note that no reversal labs use 68 degrees..they run higher and sometimes very high temperatures. Higher temperature developer for a shorter time does not behave the same as the savve developer when it's cold for a longer time. When you're doing "extreme" developing like this, the "reciprocity" of time and temperature seems to get left behind--like film for very long exposures..it acts differently.
Before you try to do solvant blindy in the first dev, I'd suggest you do it with ferricyanide bleach--you can take your current results and slowly dissolve the silver on them to "develop by inspection". It works and it's more controllable when you can see what you're doing. That hypo in the develeloper is hard to guage since there's 2 things going on at once. You won't lose any more silver than the hypo in the developer will take away--nothing to lose.
Anyways--I still firmly believe that hypo in the developer is unnecessary and therefore should be avoided.
I believe that stronger, more active developer is the way to go--you can see from your results--more power is the key--you just need more horsepower in that 10 minutes--higher temperature? more carbonate? D-11?--you have the luxury of time to develop--unlike labs that develop MILES of film--their processes must be set up for minimum time. You need a process that takes like 10 minutes to promote uniformity and to lessen the effects of filling/emptying. Even 6 minutes is pushing it pretty quick...that's why it's the starting point for this type of work.
in agreement with your comment - after my Pan-X test - I too was beginning to think that D19 is just not active enough. I've got a good image starting (after using hypo to clear the base silver) but only at 50ASA with 12mins of development. The 100 ASA exposure is unusable.
(With regards your 10 minutes rule - I absolutely could not get noticeable fogging with Tri-X. Pan-X is another story.)
I was loath to start using higher temperatures but I might give it a shot.
Working out the right relationship between developer strength/time and hypo qty does look slightly like trial and error. But I got nothing useable in Pax-X until I added it.
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.
Last edited by mr.datsun; 03-18-2013 at 06:21 AM. Click to view previous post history.