Capacity/life of rapid fixer
in [Darkroom]
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From: sreenath on 4 Apr 2010 06:29 Hi, I am using a rapid fixer sold in India be the name "Agefix" The instructions that come with the bottle just suggests a dilution of 3-5 times for film. I have been using the suggested dilution with no problem. My question is the capacity of this diluted fixer. I kept using the 1 liter for more than a year. Every time I do a film clip test and observe that film clears very quickly. Is it possible for the fixer to clear the film clipping but still be unable to fix the film completely? Are there any other tests for fixers? thanks, Sreenath
From: Peter on 4 Apr 2010 12:52 On Apr 4, 6:29 am, sreenath <sreenat...(a)rocketmail.com> wrote: > Hi, > > I am using a rapid fixer sold in India be the name "Agefix" > The instructions that come with the bottle just suggests a dilution of > 3-5 times for film. > > I have been using the suggested dilution with no problem. > > My question is the capacity of this diluted fixer. I kept using the 1 > liter for more than a year. Every time I do a film clip test and > observe that film clears very quickly. > > Is it possible for the fixer to clear the film clipping but still be > unable to fix the film completely? > > Are there any other tests for fixers? > > thanks, > Sreenath I am not sure what Agefix is. If it is the Agfa liquid fixer, then you achieve a rapid fixer by not diluting it so much. I used it for years and found it convenient. Kodak, in its book of formulas, has the formula for a simple test for fixer. My copies of that book are currently in storage. If I am near there I'll look for it. The idea of the test is simple. You make a standard solution with AgNO3 and put a specific number of drops of the solution in a specific number of mililiters of fixer. If the fixer is getting weak, you will not some white precipitate form or possibly only a very slight milkiness. If the fixer is still good enough stirring or shaking the mixture will cause it to clear. If it does not, it is used up. Kodak also has a tech tip that sounds a whole lot more complex: http://graphics.kodak.com/docimaging/uploadedFiles/techTip59.pdf It may be that the difference is that some places Silver Nitrate is hard to find. My suspicion when using such a test is that running fixer to the bitter end may leave a bit of either unfixed residue or silver complexes with the thiosulfates. Consequently, I like to use a 2-bath process where I do most of the fixing with the first bath and then let it fix in a second bath. The second bath is not depleted very much and I am happy to use the first bath until it fails to pass the test. Thereafter I discard the first bath, promote the second bath to the first bath and make a fresh second bath. If I find my formalas, I will augment this, or perhaps someone else will.
From: Stefan Patric on 4 Apr 2010 14:52 On Sun, 04 Apr 2010 03:29:41 -0700, sreenath wrote: > Hi, > > I am using a rapid fixer sold in India be the name "Agefix" The > instructions that come with the bottle just suggests a dilution of 3-5 > times for film. > > I have been using the suggested dilution with no problem. > > My question is the capacity of this diluted fixer. I kept using the 1 > liter for more than a year. Every time I do a film clip test and observe > that film clears very quickly. > > Is it possible for the fixer to clear the film clipping but still be > unable to fix the film completely? > > Are there any other tests for fixers? Agefix is an Agfa product. With standard dilution, no replenishment, 1 liter will fix 1 square meter of film before the fixer is exhausted. That's about 20 rolls of 36 exposure, 35mm film. Here's a link to the Agfa film chemistry pdf. The Agefix info is on page 12 of the document. http://www.cri.ensmp.fr/~silber/photo/docs/films.pdf Stef
From: Claudio Bonavolta on 4 Apr 2010 17:32 On 4 avr, 12:29, sreenath <sreenat...(a)rocketmail.com> wrote: > Hi, > > I am using a rapid fixer sold in India be the name "Agefix" > The instructions that come with the bottle just suggests a dilution of > 3-5 times for film. > > I have been using the suggested dilution with no problem. > > My question is the capacity of this diluted fixer. I kept using the 1 > liter for more than a year. Every time I do a film clip test and > observe that film clears very quickly. > > Is it possible for the fixer to clear the film clipping but still be > unable to fix the film completely? > > Are there any other tests for fixers? > > thanks, > Sreenath For films, a quick method is to discard the fixer once the clearing time doubles compared to fresh fixer in same conditions (film type, dilution, temperature, ...). Otherwise, you have the potassium iodide test, described in Kodak publication J-1 (page 40): http://www.bonavolta.ch/hobby/files/Kodak%20j-1.pdf There is a mismatch in that page where some blocks of text do not follow each other properly. Claudio Bonavolta http://www.bonavolta.ch
From: Richard Knoppow on 4 Apr 2010 17:33
"Stefan Patric" <not(a)this.address.com> wrote in message news:Hd5un.57294$y13.23103(a)newsfe12.iad... > On Sun, 04 Apr 2010 03:29:41 -0700, sreenath wrote: > >> Hi, >> >> I am using a rapid fixer sold in India be the name >> "Agefix" The >> instructions that come with the bottle just suggests a >> dilution of 3-5 >> times for film. >> >> I have been using the suggested dilution with no problem. >> >> My question is the capacity of this diluted fixer. I kept >> using the 1 >> liter for more than a year. Every time I do a film clip >> test and observe >> that film clears very quickly. >> >> Is it possible for the fixer to clear the film clipping >> but still be >> unable to fix the film completely? >> >> Are there any other tests for fixers? > > Agefix is an Agfa product. With standard dilution, no > replenishment, 1 > liter will fix 1 square meter of film before the fixer is > exhausted. > That's about 20 rolls of 36 exposure, 35mm film. > > Here's a link to the Agfa film chemistry pdf. The Agefix > info is on page > 12 of the document. > > http://www.cri.ensmp.fr/~silber/photo/docs/films.pdf > > > Stef The real test for fixer is the residual silver in the emulsion. There are two simple tests. One is about a 2% solution of sodium sulfide (not sulfite) the other is a 1:9 dilution of Kodak Rapid Selenium Toner. Either will tone the remaining halides or silver complexes readily leaving a stain. A drop or two of the solution is placed on _wetted_ film or paper and left for a couple of minutes, they rinsed off. It should leave NO stain if the emulsion has been completely fixed. With any fixer the capacity can be much extended by using two successive baths. This technique extends the ability of the fixer to completely fix from four to ten times. Instructions for the technique and for the test solutions can be found in the _Kodak Black and White Darkroom Data Book_ I don't know if this is still published but old editions have the same information in them. The problem is that an exhausted fixing bath will continue to clear emulsions long after it has become too exhausted to completely fix out all the silver halide. The complexes left in the emulsion will change over time to a form which can no longer be removed by re-fixing and will eventually destroy the image. -- Richard Knoppow Los Angeles, CA, USA dickburk(a)ix.netcom.com |