PMK volume effect on density

[ed_lajoie]

My initial ASA test on Ilford FP4 showed ASA100. I developed the

test in PMK @ 70 degrees--5,10,500ML. Test exposures at ASA100

proved over exposed when developed in PMK @ 70 degress--10, 20,

1000ML. Has anyone else experienced shifts in ASA when increasing

or decreasing the AMOUNT of developer or should I go back to the

drawing board?

[david_goldfarb]

I could see that happening if the developer were becoming exhausted at the smaller volume. PMK is very dilute at normal strength, so this is something to be aware of.

 

One recommendation I've seen is to use 500ml developer of working solution at 1:2:100 per 35mm roll, 120 roll, 8x10" sheet or equivalent, because these are all about the same area of film. That means using twice as much for a 35mm roll as you normally would in a conventional daylight tank, and you would have to double the quantity of developer for 220, since the reel takes the same amount of space in the tank, even though there is twice as much film.

 

Another possible problem could be oxidation with the lower volume, if there is a lot of air space in the tank. I own tanks of various sizes to avoid this problem, and these days you can find used stainless steel tanks in perfectly good condition for cheap. Replacement lids are available from B&H, as long as the tanks are standard size.

[tim_curry]

Ed,

Are you talking roll film or sheet film? I think asa 100 is somewhat optimistic for FP4+ and would normally expect it to show weak shadow detail at 100. I use 330ml for 35mm roll film and have no trouble with developer being too exhausted upon completion. I have found no shift due to increase or decrease in volume. Are any variables different: time, temperature, agitation cycles, water source, measuring devices?

 

Something is wrong somewhere. Go back to step one and see what may be different. I have found PMK to be very reliable when used consistently. I use it for 35mm in a tank, 4x5 in an old yankee agitank and for tray development of 8x10. Please let us know what you find out.