Chemical question (reddish tinted fixer after processing)

[ramsdell photography]

<p>I've noticed lately when I am developing BW film that the fixer after I am done with it and pour it back in the jug has a reddish tint to it that it didnt have when it went into the developing tank. Any ideas? Thanks.</p>

[lex_jenkins]

<p>That's fairly common these days. In addition to silver halide many b&w films use various dyes - anti-halation and sensitizing - which are soluble in water and darkroom chemicals. Generally these dyes are harmless and will not impede the effectiveness of reusable chemicals such as fixer.</p>

<p>Some films, particularly European films (other than Ilford) will release blue-green dyes during the development stage. Some photographers prefer to use a pre-soak to remove these dyes, especially if they reuse their developers (typical of replenishment systems, stock solutions and some two-part developers).</p>

<p>For the past decade Kodak and Ilford films use dyes that are a bit more stubborn and tend to leave a slight tint on the dried negatives, variously described as blue, purple or magenta. While the film manufacturers have repeatedly assured users that a slight residual tint is harmless some photographers become rather obsessed with desiring neutral gray negatives and resort to extraordinary methods to remove the tint, ranging from extended fixing times, hypo clearing agent, aggressive agitation and other tricks.</p>

<p>Other photographers have suggested exposing the finished, dried negative strips to sunlight or strong UV light for several hours to clear the slight residual tint.</p>

<p>Solubility seems to depend on whether the dyes are incorporated into the emulsion or into the film base itself prior to emulsion coating. Certain developers, especially Rodinal and Neofin Blue, will aggressively strip out these dyes. My rolls of Kodak Tri-X and T-Max films, developed in Rodinal, will pour out a bright purplish-blue offal when the one-shot developer is dumped after use. The negatives will dry with a neutral gray finish. But I don't always want to use these developers on these films, and I'm not that concerned about the dyes.</p>

<p>If you reuse your fixer (which is a good practice, since it's wasteful in one-shot use), you might want to filter it occasionally to minimize the risk of sludge or debris adhering to your next sets of negatives. No special materials are needed for filtering. Some folks suggest cotton balls in a funnel; I've used those "gold" metal fine mesh coffee filters. Paper coffee filters tend not to work well unless there is something in the filter basket, and since we probably don't want coffee in our fixer, perhaps a neutral bulking substance such as tiny pebbles or gravel might help.</p>

[jpo3136b]

<p>If it comes out okay; it came out okay. It sounds like yours came out okay. </p>

<p>If you're seeing a color change in a solution, and the roll is not coming out, that's another story. And that usually ends up with clean up, start over and try again. </p>

<p>A given color might be evidence of a variety of causes. The red looks like Red; the pink looks like Pink, etc.; but the chemical composition of a "pink" solution could be a bunch of stuff. If a color change's general description is the only indicator, that can lead to less efficient troubleshooting. So, I wouldn't recommend spending a lot of time on what's in a color unless you've got access to some real lab equipment like a spectrometer or something. In the end, it won't matter much anyway. By the time the roll is wet, it's pretty much spent. Just keep going. </p>

[ronald_moravec1]

<p>The dye color I get disappears over time. <br>

I do the cotton trick, in fact I invented it as far as I know. I got the idea from a book I read in 1960 about the original X1 rocket plane Chuck Yeager used to break the sound barrier. Some substance was needed to filter the rocket fuel and Kotex was all that was available in sufficient quantities. I translated that to a filter substance in about 2000 for fix and it works.</p>

<p>Disolved dyes do not filter out. Only solids. Paper coffee filter are worthless except to hold cotton in place. The gold filters are a good idea, but I have not tried them. </p>

<p>I do not reuse film fix, but I do use it up on test prints. Do not use it for final prints.</p>

<p>You really need to filter used fix to reuse it on film as some silver comes out of solution after 24/48 hours and will contaminate the next film. That`s the black stuff on the bottom of the fix jar. </p>

[ramsdell photography]

<p>Well hey thanks folks for the great awnsers! It hasnt affected my negatives at all so I was just curious as to what it was. Mainly because I didnt remember that happening when I used to develop film in college. But excellent awnsers! Thanks!</p>

[ramsdell photography]

<p>Mr. O'Keefe-Odom, are you by chance related to the Odom's of Monhegan Island, Maine? Just curious.</p>

[john_shriver]

<p>I see this with T-MAX films. What I notice is that 5 minutes in the light in the laundry room, and the fixer isn't pink anymore. It must be the sensitizing dye (unexposed T-MAX films are somewhat magenta colored anyway), and they break down pretty quickly in the light.</p>

[larrydressler]

<p>You should see my Diafin solution A I have been using it for some microfilm and it is so pretty in pink.<br>

That said I started using a pre soak with some films ACROS is 1 and I get a nice clear or tonal gray base when I am done depending on the film even Tri-x lost the purple...</p>

[jpo3136b]

<p>Jared, no. If there's any connection, it's so distant that we don't know about it.</p>

[wendell_kelly]

<p>I shoot mostly Fuji Neopan 400 and find that the antihalation dye leaches out in the hypo clearing bath (Ansell's formulation) rather the acid fixer (F5) that I use. The dye in Kodak TMax 1600 seems to resist leaching in either bath and my negatives retain some color.</p>

[steve_swinehart]

<blockquote>

<p>Other photographers have suggested exposing the finished, dried negative strips to sunlight or strong UV light for several hours to clear the slight residual tint.</p>

 

</blockquote>

<p>I have a fluorescent light inside my film drying cabinet. I put the film in to dry, turn on the light and when the film is dry - the residual dye color is gone. No need for "strong UV" light - a fluorescent light has enough UV to neutralize the dye in 2-3 hours.</p>

<p>I've been using the fluorescent light since about 1982 - always works.</p>