I suspect that the recommended 1-2 minutes for fix that they recommend is directed to fixing paper.
These are the times:
from (sorry, this is in dutch):
The efficiency of the fixer might relate to the pH of the gelatin. If so, the lack of an acidic stop bath might be a part of the issue. And if the fixer isn't well buffered, its pH might be changing due to the minor amounts of developer carry-over that inevitably come with a plain water rinse instead of a stop bath.
“Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”
Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2
Fixer is the same thing as hypo. Hypo is an old fashioned term for fixer.
Originally Posted by Aerial
Hypo Clearing Agent is a Washing aid that helps to remove fixer or hypo.
"She's always out making pictures, She's always out making scenes.
She's always out the window, When it comes to making Dreams.
It's all mixed up, It's all mixed up, It's all mixed up."
From It's All Mixed Up by The Cars
Originally Posted by wildbill
Your answers are all in the discussion linked to above. This is an ongoing topic and has been dealt with a lot.
If I might summarize and edit the whole discussion according to my understanding:
First, consensus is that the pink cast in many films exhibit even after seemingly adequate processing come from sensitizing dyes that are difficult to wash out. A very slight pink/purple cast can be ignored if you are sure your processing is good. However, more than just a little or increasing discoloration is a sign of inadequate fixation and you should re-fix and rewash any negatives that exhibit more pink/purple than benchmark negatives processed more than long enough in fresh fixer.
Most of us have a strategy for dealing with the pink cast that includes longer fixing times, use of a wash aid and extended wash times in some combination.
Fixing for longer will not damage negatives and is likely the most effective way to get rid of the pink. Since film is coated on a waterproof base, fixing times can be safely extended to 2-3 times the manufacturer's recommended maximum with no ill effects. Yes, fixing too long will begin to bleach film, but this effect shows up only after really long times; I've fixed film in rapid fixer for 15 minutes with no noticeable bleaching. FWIW, I fix Tri-X and T-Max negatives for 6 minutes in fresh rapid fixer using two-bath fixing (3 minutes in each bath). Your 90 seconds of fixing likely isn't doing the job.
Wash-aid helps too, but don't use it if you use a staining developer (pyro, PMK, Pyrocat, etc.) since it will remove the stain.
I wash for a minimum of 30 minutes (but I don't use a wash-aid since I use a staining developer; if I did, 20 minutes would likely do the job).
Some observations on fixing and fixer exhaustion in general:
Yes, do your clip tests! And do them before each batch to arrive at a minimum fixing time. Some think that one clip test gives them the time for the entire capacity of the fixer. Wrong! Check the clearing time before every batch to be sure.
Most importantly, a clip test is useful to see if your fixer is exhausted. Discard the fixer when the clearing time is double that in freshly-mixed fix.
I think that three-times the clearing time is the absolute minimum fixing time. After reading lots, especially work by Michael Gudzinowicz (who has a rather erudite discussion of extending fixing times for film that is really convincing), I have decided that extended fixing of film is the best way to go to both ensure adequate fixing and deal with the pink. Even though my films all clear in well under 60 seconds (usually 35-45 seconds) in rapid fix, I still give a total of 6 minutes fixing time (divided between two baths; another practice gleaned from the work of Gudzinowicz). This is more than twice as long as the "minimum" time, but not long enough to do any damage and it gets rid of the pink.
Using an acid stop bath with acid fixers (especially if you are storing the fixer for later re-use) is best practice and ensures optimum longevity of the fixer. Even the alkaline fixers TF-4 and TF-5 were designed to be used with an acid stop. If you are carrying over a lot of developer to your fixer, you are likely changing its pH and its effectiveness (although a clip test should show this).
Fixer has a lifespan as well as a capacity. Keep track of how long you store your fixer. Concentrated in full bottles last a long time; working solutions in half-full bottles not nearly as long.
Finally, Fixer Is Cheap: When in doubt, mix fresh.
Hope this helps,
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Since I took the advice from knowledgeable members here and started clip testing before each fix I've seen how fix time changes after each use. I mixed up a fresh batch of Kodak Fixer about two months ago. The 1 liter working bottle I use has had 6 rolls of 135-36 Tri-X through it. The first roll clip test had a 3.5 min clearing time. The last roll I did this weekend had a 5.75 minute clearing time. Definitely do a clip test!
Originally Posted by Doremus Scudder
Where did you hear that wash aid / hypo clear removes stain? It's the first time I've come across that information. I'm surprised by it. Thanks.
The Book of Pyro by Gordon Hutchins is my source for this, but I don't have my copy at hand to give you a page numger.
Originally Posted by Marco Buonocore
Anchell's The Darkroom Cookbook, 3rd ed. also mentions that sodium sulfite inhibits image-forming stain in staining developers. On page 62 in the discussion on pyro developers it says, "In any event, avoid using hypo clearing agent (HCA) when using pyro developers as the high concentration of sulfite in them will remove the stain." It also recommends using fixers with a low sulfite content for the same reason.
I believe it to be common knowledge as well.
And I know first-hand that selenium toning a pyro negative to try to increase contrast will strip all the stain from it, thus negating any effect from the attempted intensification.
I will second this comment. Acidic stop baths are really good at stopping development, and preventing problems that may occur if you don't properly neutralize all of the developer before it goes into the fixer.
Originally Posted by MattKing
"Often moments come looking for us". - Robert Frank
"Make good art!" - Neil Gaiman
"...the heart and mind are the true lens of the camera". - Yousuf Karsh
I've got the book of pyro somewhere down in the darkroom - I'll have to look through it. It does come as a surprise, because I know Sandy King used a 1% sodium sulphite solution as part of his washing protocol, and wrote specifically that neither that nor prolonged washing influenced the stain. I suppose I should see for myself though - I've got a lot of film to process right now so it's as good a time as any.
Sorry for derailing the thread.