Ode to FIxer
(that magical elixir)
Refuses to let memories be missed
but, fortunately, allows them to persist
Rather than (justifiably) helping me trash my prosodic attempt for reasons of metric inconsistency and contextual naivety, try, instead, to understand that all films are not created equal. (That is a worthy digression.)
When you really look hard, films do react quite differently to the fixation process. Few will note this dichotomy as very extreme because most of us use rather ‘standard’ films which show merely ‘some’, but not overwhelming, disparity in the willingness to shed silver halide.
However, I have been working in a darkroom for 48 years (1964, age 14) and have had many different films within my grasp during that time. Many of these are now discontinued, but many of them I still have, unexposed. I have tried to present a continuum, below, which points out this great difference in films’ ability to be cleared. And I have tried to present my results using a simple paradigm that is clearly understandable and can be utilized without much deeper thinking.
First, I based my results upon the ability of certain films to withstand degrees of film strength fixer (FS FIX) dilution. I am standardizing the working solution here to 240ml, the smallest volume needed to process a full, 36 exposure roll of film (ie, using a stainless steel tank). 'One shot' is best but you might be able to run two 36 exp films in this working solution. Now, the dilutions.
When I say 100% FS FIX, I am simply stating undiluted, film strength fixer. When I say, for example, 25% FS FIX, I am stating a working solution fixer composed of 60ml of FS FIX and 180ml water. Again, with 10%, that working solution is composed to 24ml FS FIX and 216ml water. The full fixation times in all cases are about five minutes at ambient temp (about, in my case, 80 F) with frequent agitation, regardless of dilution. You can see that the differences in fixer strength are astounding. But, beware of this if you attempt what I have offered: judging full fixation encompasses more that merely looking at the clear film with reflected light. Instead, being wary of lingering halides, I always look at the clear base in front of a lit light bulb and use a magnifying glass to confirm full, complete fixation. Again, 'one shot' is best, but you might be able to do two 36 exp rolls using the same 240ml working solution. And, importantly, do not attempt this dilution for paper as paper requires much fresher fixation due to by-products that can affect the paper’s ability to be washed effectively. The film continuum, below, goes from easiest to fix to hardest to fix.
Kodak: ImageLink (microfilm), Ultratec, Kodalith Ortho, Recordak: these can be fully fixed in the five minute process using an astounding 5% FS FIX. Yes, using only 12ml FS FIX in 228ml water will fully fix these films.
Next is Kodak Panatomic X film for which I use 12% FS FIX.
Next are Ilford Pan F +, Ilford FP4+, Ilford Delta 100, Kodak Plus-X, and Agfapan 100, for which I use 17% FS FIX.
Next are Kodak Tri-X, Ilford HP5+, Ilford Delta both 400 and 3200, and most other ISO 400 films for which I use 25% FS FIX.
Next are the Kodak T Max group (100, 400, 3200) which need 50% FS FIX.
Finally, there is a discontinued Kodak film, Recording 2475, which, perhaps due to iodide in the film, is extremely difficult to fix completely unless the FS FIX is 100%. – David Lyga
That seems to jive with what I remember; slower emulsions require less fixer activity than faster emulsions.
Wow, interesting comparison. I once watched a guy fixing Delta 400 in Ilford Rapid Fix 1+9 and the film didn't clear. Redoing it in 1+5 soup did the trick. Your numbers fully support what I have witnessed.
I like the idea of using one shot fixer. Your observations will be useful in determining dilution. Thanks David.
Sorry, I forgot the venerable Technical Pan. Give it a good old 17% with the Plus-X. And Bain from Ottawa, don't be so quick to come to conclusions. Remember, Panatomix-X and Pan F+ are the same speed but require DIFFERENT fix times. Delta 3200 fixers lots faster than T Max 3200. It usually is the case that the slower the film the quicker the fix, but not always. That Recording 2475 Film is a disaster to fix. But the ImageLink Mircofilm (and its cousins) are indeed worthy of only 1/20th as much fix as the Recording film.
And, of course, folks, frequent agitation; and my 'ambient' is 80 F, not 72 F. - David Lyga
I remember that Panatomic X was rated at ISO 32 whereas Pan F was rated at ISO 50, a 2/3 stop difference in sensitivity. I stand by my observation as a generally useful principle.
Originally Posted by David Lyga
Microfilm is a bit different in that it is made to have more or less single size (small) grains, which is why it takes special development to get Pictorial Images.
(I used a lot of microfilm at work in my working years in Ottawa)
Bain, to me, the REAL speed of Pan F is 25, not 50. And even Ilford allows for this possibility in their development chart. - David Lyga