Proper fixing timesgreenspun.com : LUSENET : Large format photography : One Thread
I've found a number of questions on various photo forums lately regarding a pink or cyan stain on negs remaining after developing/processing. Most answers relate the problem due to inadequate fixing or exhausted fixer.
Most published advice regarding adequate fixing times in some way or another say to fix 'twice as long as it takes for the film to clear'. My question is, what exactly am I looking for? The most concise explanation I could find is Kodak's recommendation to fix twice as long as it takes until the film loses it's 'milky' appearance. I also remember reading somewhere that the proper way to determine fixing time is to put a sheet of undeveloped, unexposed film in the fixer and note the time it takes for the film to lose it's 'milky' appearance and fix for twice that time. I guess 'milky' is, at least for me, a somewhat vague description. After about 35 seconds in Ilford's rapid fixer (1:4) with the test mentioned above my film (Tri-X ) does become 'clear' though with a definite pinkish cast. Does this mean that 70 seconds is the proper fixing time with this film/fixer combination? My usual practice has been to fix in Ilford's rapid fixer for 5 minutes then rinse in running water 2 minutes before moving to a HCA wash.
Regarding the pinkish cast, my understanding is that this is related to the anti-halation dye and not necessarily an indication of proper fixing times. I always find a pink color remaining within my pre-soak water and it usually is not eliminated from the film entirely during fixing. It is almost always completely gone after the two minute water rinse.
Could somebody please elaborate on proper fixing times for me?
While I've got my two minutes with the microphone, I'd like to give a hearty thanks to all of those who regularly contribute their expertise to the large format forum. Without question, this is the best photo resource on the internet. Not only is the advice always on the mark, it always seems to be offered in a genuine spirit to help fellow photographers - a far cry from the often petty personal attacks found on other forums, even photo.net.
-- Andy (firstname.lastname@example.org), July 06, 2001
That milky effect is more easily seen when looking at the emulsion side of of a sheet that is in the fix. The pink cast is indeed left over anti-halation dye, most of which does seem to dissolve out when the film is pre-soaked in water. T-max 400 will actually leave a purple Kool-aid looking solution when pre-soaked. When the fixer becomes weakened, it's less effective in eliminating the last of the dye. I can usually detect this tendency soon enough so that the few minutes that my sheets remain in a holding tray of water are enough to rid them of the last of the dye. I then make up new fixer for the next batch of films. In cases where I have discovered the pink tinge after processing, I have prepared a solution of Sodium Sulfite and soaked the negatives first in water and then in the SS solution for a few minutes, re-washed and dried.
-- Robert A. Zeichner (email@example.com), July 06, 2001.
Oops, I meant to say the milky effect is better seen from the backing side rather than the emulsion side.
-- Robert A. Zeichner (firstname.lastname@example.org), July 06, 2001.
For some years I have used film strength rapid fix for two minutes with continuous agitation for all films. When T-Max came out, Kodak recommended increasing the fixing time to help eliminate the red dye in the emulsion. I use 3 minutes for T-Max. I never use fix much beyond half the recommended capacity. Kodak states that one quart or liter of their rapid fix at 1:3 will fix 32 8x10 inch negatives--I generally mix 2 liters at a time and use it for 40 8x10's. Since I occasionally stray into roll film, I count one roll of 120 or one roll of 135 as one 8x10 inch sheet. Kodak states that T-Max depletes fixer faster than other films--I count two 8x10 sheets of T-Max as three. I put a piece of black photographer's tape on the bottle of fix and make a mark in white grease pencil for every sheet or roll I fix.
I have found that three minutes, with agitation, in PermaWash eliminates the red dye in T-Max completely. I use 10ml of PermaWash in 500ml of water. It also reduces the wash time.
-- Ed Buffaloe (email@example.com), July 06, 2001.
Just a brief comment. I can only speak for the T-Max films because that is what I have experience using. Recently I demonstrated for some students that this talk of fixing to get rid of the pink or purple is not easily possible particularly with T-Max 100. I left a sheet of T-Max 100 in a tray of new rapid fix for over an hour and the pink cast was still there. Then we placed a sheet of processed film in a large tray of water for 10 minutes and the water turned bright pink. I think this basically shows that adequate wash times are imortant to correcting this problem. I am not discounting the need for proper fixing but I know photographers that only give a few minutes of wash and call it good, this is just not enough.
-- Jeff White (firstname.lastname@example.org), July 06, 2001.
Andy: In my experience, this is one of the less time-critical steps in B & W processing. For Tri-X, using Kodak rapid fixer, I find the film clears quite quickly, often within a minute. Another minute or two and the pink/purple tint goes almost entirely away, then I wash it. 10 minutes of washing will remove the pink color. I normally don't bother with Permawash, etc. on Tri-X. You don't have the "hypo binding to the paper fiber problem" with film. Is this archival? I have strips of tri-x 35 mm which I exposed and processed in high school (Class of 1973) which are stuffed in a grocery bag in my Southern California attic. Temperatures are often in the 100+ degree range (F, of course) and other than being really dusty, they are fine. Many got less than 10 minutes of water wash and they still look fine. TMAX is different. Even in fresh Rapid Fix it takes longer to fix, an extra 5 minutes or so will almost get the pink out. You're going to have a hard time overfixing film. TMAX does seem to wear out fixer more quickly. A lack of agitation combined with somewhat depleted fix will leave more pink. If a 10 minute wash still leaves some pink (usually this is not the case) I put them in Permawash and at least in my experience the pink then goes away like magic. A few minutes more wash and you're ready to dry them.
-- Kevin Crisp (KRCrisp@aol.com), July 06, 2001.
I've been using FP4+ sheet film with Ilford Hypam (1:4) and the Ilford instruction says to fix film for 4 min if a hardener is used. I did an unexposed film test in the fixer and it clears within 45 sec. To fix twice the clearing time at 1 1/2 min is in my opinion too short. Steve Anchell's recommendation is to fix thrice the clearing time. That seems also a little short too, I think. It seems like there is no one proper fixing time that people can agree on. So, I've been following the manufacturer's 4 min. fixing. Would that have been over-fixing? If so, do I expect to have damaged negs in the long term?
-- Aaron Ng (email@example.com), July 06, 2001.