Pan F, Rodinal, Densitometers, Zone VI VC Heads and Zone VIII
Well, now that I've completed my move I'm finally building a darkroom big enough to handle my Zone VI VC enlarger, etc.
Since basically everything is changed and I now have access to a densitometer (thanks to the friendly radiology staff at the local hospital), I decided to go through a new round of film testing using the Zone 2 Tone method. Since Pan F+ and Rodinal 1:50 are one of my favorite combinations I decided to start there.
My first go was with Rodinal 1:50 for 15 minutes at 68 degrees (Agfa's recommendation). This produced a B+F of .31, a Zone I density of .41 (right on, eh?), but a Zone VIII density of 2.14. Way over developed.
The next attempt was Ilford's recommendation of 11 minutes. This produced the same B+F, a Zone I density of .51 and a Zone VIII density of 2.01. This would seem to indicate that I need to underexpose and reduce the development time still further in order to get Zone VIII to B+F + 1.30. I'm planning on trying 8 minutes next, which seems quite low to me for 1:50.
I would like to know if anyone else has gone though this testing for this combination and what their results were. Also, for those who do densitometer testing and use Zone VI VC heads, what density range do you seem to get the best results with for Ilford and Agfa MG type papers?
Up to now I've always been a "Go with whatever looks good" kind of guy, so this is my first bout with the Zone system and testing.
Any thoughts would be appreciated.
Since it's one of your favorite combinations, what is your normal processing time? In your two tests above, what film speeds did you use? The numbers look a bit funny to me, unless you used different film speeds for the two tests. I would expect your past times would be a good basis for speed and contrast tests.
Originally Posted by BruceN
FWIW, in the recent Agfa pdf for film chemicals, the time for PanF+ and Rodinal 1+50 is 12min at EI=64, 20degC, small tank (not rotary), contrast=0.65 (a bit high for most of us). Taking a guess for contrast=0.55, based on the ratio of Agfa's times for APX100 (only rotary times are given for different contrasts for some reason) would lead me to suggest a time of 12x4/7=7min. This is complete guesswork. I would not expect a speed of 64 though. Probably half that.
Fred, being as you are going to really dig in now, I highly recommend giving Fred a call at the view camera store and talk to him about the btzs system.
Your base plus fog measurements are entirely too high. Something is wrong with those measurements. They should more typically be .04 to .08. I am not sure what is wrong could be the film is fogged. How fresh is the film? How are you developing? What is your agitation method?
I started back testing this combo this winter, but didn't get far, and only developed a 35mm roll with no solid tone test frames. As I recall, I went 1+100, 12 minutes, 20C, with a couple of inversions each 30 seconds. My negatives were a little underdeveloped, but I don't have any sensitometry on it. Then I tried Efke 25 and haven't gotten back to the PanF+. I've always done the slower films, Agfapan 25, Panatomic-X, and Pan-F at 1+100 in Rodinal, so I don't have any times from old memory at 1+50.
I recently did a roll of Efke 25 at EI 25 and titrisol's recommended lesser agitation, one inversion every 2 or 3 minutes after the first minutes, and got gammas of about 0.6. There's another thread here discussing that tactic with PanF+: http://www.apug.org/forums/showthrea...highlight=efke but it came to no final conclusion.
I'll attach a frame from last week with Efke 25 at the lower agitation rate, one inversion every three minutes after initial agitation of 45 seconds, and with a 3 minute presoak.
In any case, I'd recommend a shot at reduced agitation and perhaps greater dilution as well, as ways to keep effective film speed up while controlling highlight densities.
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
I'm a little embarrassed to say it, but before I've always just split the difference between Agfa's recommended time of 15 minutes and Ilford's of 11 minutes, giving me a time of 13.5 minutes. I bracketed the heck out of my exposures in order to come up with something printable. That's one reason I've decided it's time to "get serious." You're right about the numbers, I think I must have slipped an f stop on the second Zone I strip.
Originally Posted by john_s
This film isn't the freshest, but it's been kept cold. I also shot very fresh rolls of FP4 and HP5 and got B+F measurements of .34 and .39, respectively. (I'm doing all of these tests in 35mm initially) The densitomer is sent off for calibration on a regular basis and is checked against a test strip frequently (hospital rules), so I don't think it could be off.
Originally Posted by Donald Miller
Agitation could be a bit too vigorous. I agitate for the first 30 seconds, then 5 inversions every minute. I'm very careful about temperature, keepiing the tank and chems right at 68 degrees.
Originally Posted by BruceN
I do have the same experience as you with the ZONE 2 TONE (test method). I tested HP5+ 5x4" (fresh) with Ilford's DD-X. I also send my densitometer to the servicedept of that company to check and calibrate again. And metered al negs again with the same results.
Zone I should be 0.10 and Zone VIII 1.29.
The results where:
test 1, DD-X 1+4 at 7'45":
Frame no.; ZONE I=0.10; ZONE VIII=1.29; SPEEDSETTING; B+F
1; 0.12; 1.08; 400; 0.17
2; 0.08; 1.06; 500;
3; 0.16; 1.16; 250;
4; 0.40; 1.31; 200;
test 2, DD-X 1+4 at 9'00":
Frame no.; ZONE 1; ZONE 8; SPEEDSETTING; B+F
1; 0.12; 1.14; 400; 0.14
2; 0.17; 1.14; 500;
3; 0.24; 1.24; 250;
4; 0.29; 1.27; 200;
After this I did an single test at 400 ASA and dev.time 10'00";
1; 0.14; 1.26; 400 0.11
(There is going something wrong with the table. Read the table as follows, every ";" is end of colomn)
I never reached the most ideal values for this test as mentioned in that article. When Zone I is fine than Zone VIII is to less or vice versa. So I am little confused with this result and stopped testing at this manner. If somebody has an idea where its going wrong or what I have to do, please let me know.
Release, the best you can do...
The film speed test is very straightforward -- figure out what gives you .1 over fb+f as you are doing. When doing this test, though, pay absolutely no attention to Zone VIII. I have consistently found that the exposure index in these tests almost always comes out to be 1/2 the rated ASA; for Pan F, I use EI 25.
Once that is determined, I believe wholeheartedly in the tests that Fred Picker outlined. Get your "proper proof" time using unexposed but developed film to get the minimum exposure needed to produce a full black in the fixed/washed/dried print (this takes the "dry down" factor into account). With the proper proof procedure under your belt, and an accurate EI for the film used, go out and shoot an entire roll of Zone VIII exposures (or four or more sheets if you're using LF). Develop 1/4 of the roll for the manufacturer's suggested time, 1/4 for 25% less, 1/4 for 25% more, and then "proper proof" them all to see which one SHOWS a Zone VIII density. At this point, the densitometer doesn't matter -- it's all in the visual evidence. If you cannot get a visual Zone VIII density from one of those three strips, then adjust the development of the last one to put you in the ballpark. You should be very close to the proper development time at that point.
My development time for Pan F at EI 25 with R-09 (J&C) developer is around six minutes with it diluted 1:100. I found the times too short at 1:50, but with the larger dilution and more time, the results have been stunning.
I hope this helps. It's very easy to over-complicate this stuff, when it's all really quite simple. Just remember you only need the densitometer for the film speed test; after that, it's all visual and the only thing that matters is what the eye sees.
By the way, one other quick note. When you make the Zone VIII exposures, use a LARGE white card outside in sunlight in order to approximate most closely real conditions. It will also be much easier to judge the proper proofs to see detail in the card if you have other stuff around it and not just white only in the neg.