Blue Color in Pre-wash of Film

John Irvine · Jul 5, 2008

Tonight, when I poured out the first step water wash in developing a roll of film, it was a very deep blue color. Very much like the color from an indicator in a basic solution. I cannot figure where that could have come from. The details are:

Distilled water, stainless tank & reel, 20C, 120 roll of Tri-X 320TXP. The tank was dry and had been stored with the lid on since the last use.

After all the processing and rinsing 30 minutes in running water, the film base is more purple than I expect to get with this film.

While still wet, the negatives appear to be about what I would expect of the subject so nothing may be lost, but I would like to know what happened.

Tom Hoskinson · Jul 5, 2008

You probably washed out the anti-halation dye - or most of it - and maybe some additional dye.

No problem.

What film was it?

Tom Hoskinson · Jul 5, 2008

Sorry John!

You told us it was 320TXP!

Otherwise, my answer remains unchanged, except that soaking the film post-fixing, in a 20gram per liter solution of sodium sulfite in water should help to remove any remaining dye.

arigram · Jul 5, 2008

Its normal.
As Tom said, you just washed out the anti-halation dye of the 120 film, which normally leaves with the first wash, being the pre-wash water or the developer. The dye keeps the film from being exposed by any reflecting light that gets inside the backing paper.
As far as being too purple when it comes out in the end, thats due to the fixer.
Usually it means that you haven't fixed the film enough, but depending on the color and the film it might just be fine.
Fix for longer next time and be careful about reusing the fixer.

Sean McEntee · Jul 5, 2008

Hi, I'm relatively new here and I want to say how it gladdened my heart to read John's question. It is evidence there are still people who are taking up film and treading the path. I remember the first time I saw the "blue rinse" and had the same feeling of "what on earth is that?"

I love the smells and colors of the darkroom, 35 years haven't dampened the romance.

Christopher Walrath · Jul 5, 2008

Yup. The blue means it working . . .

fschifano · Jul 5, 2008

I'm compelled to ask why you bothered with a pre-rinse? There's no need for it and it serves no useful purpose. I used to do it myself many yeas ago in a misguided attemp to temper the tank. Now I just put the tank into the tempering bath with the rest of my chemistry and it's no longer a concern. The tank goes back into the tempering bath between agitations. When I use a plastic tank and the twirling stick for agitation, it never leaves the tempering tank. Place a weight on top of the tank if it wants to float.

John Irvine · Jul 6, 2008

I use the water wash because every source tells you to and it makes sense to me to have everything wet and all air bubbles displaced before briinging on the developer.

I guess the anti-halation is only in the roll film and that is why I haven't noticed it in 4X5.

And the purple color could be a weak fix. I didn't get the color on the previous roll which was the first thing fixed in this batch. I hnever have been able to keep track of how much I have used a batch of fixer.

Will the sulfite bath still work after drying? Is it worth the effort?

fschifano · Jul 6, 2008

I don't know what your sources are, but Kodak mentions a pre-wash only for sheet film processing in trays, saying, "Prewetting sheet film may improve tray process uniformity." This makes sense. The sheets won't stick together upon immersion into the developer tray and developer induction is slowed down a bit. Read it on page 5 here: http://www.kodak.com/global/en/professional/support/techPubs/f4017/f4017.pdf. Other than that there is no mention of pre-wetting. Ilford recommends against the practice, and you can read on page 3 in this document: http://www.ilfordphoto.com/Webfiles/2007321132461251.pdf.

JPD · Jul 6, 2008

John Irvine said:
I guess the anti-halation is only in the roll film and that is why I haven't noticed it in 4X5.

No, most sheet films and glass plates have anti-halation layers. They are there to reduce reflections from the surfaces of the film/glass base, pressure plate, backing paper and film holders.

It's strange though, that the dye becomes clear in some developers, and not in some.

Photo Engineer · Jul 6, 2008

The dyes reduce halation as stated, but they also increase sharpness and trim the speed and color sensitivity of films so that they have the correct balance.

Kodak does recommend and has always recommended a prewet for all film, but this is not clearly stated in all publications. This has led to confusion.

A prewet tempers the tank and also helps alleviate air bubbles which cause small white dots of undeveloped areas to be found on the film.

It is not necessary if one is using deep tank processing with nitrogen burst agitation, as the rather violent agitation from the nitrogen helps disperse the air bubbles, but you still must rap the equipment hard during the first 30" to dislodge the bubbles. That is also a good idea during the prewet.

PE

srs5694 · Jul 6, 2008

I've seen many threads here and elsewhere about pre-washes. Some people use them, others don't. A few in either camp get agitated about the practice -- "pre-washing causes global warming" or "failure to pre-wash causes kittens to die," etc. As with so many things in photography, there's no right or wrong on this issue, although one method or another may work better in specific circumstances (pre-washing could interact with the developer you use, for instance). Just pick a method and, if it works for you, stick with it. Consistency is more important than which method you use.

mjs · Jul 6, 2008

Note that not every film's anti-halation dye washes out as blue. Foma's 200 speed film (I use it in 8x10 sheets,) is a beautiful emerald green. Tmax 400 (not the newest,) is a royal blue. I guess that blue is the most common; I'm still looking for a deep red one!

Mike

gainer · Jul 6, 2008

Usually a bit of sodium sulfite removes it or at least bleaches it. You needn't worry about it. It has done its job by the time you prewet the film. You could try adding a pinch or so of sulfite to the colored wash just for fun.

ntenny · Jul 7, 2008

mjs said:
Note that not every film's anti-halation dye washes out as blue. [...] I'm still looking for a deep red one!

Efke 100 (in 9x12, anyway) produces a nice cherry-soda sort of red.

I seem to remember somebody here saying that the prewash water from Tech Pan, I think, came out *black*, which seems like it would be pretty startling.

Why is there so much variation in these dyes? It seems like they have a pretty simple job, and I'm kind of surprised there isn't a single obvious Right Way To Do It.

-NT

arigram · Jul 7, 2008

ntenny said:
Efke 100 (in 9x12, anyway) produces a nice cherry-soda sort of red.

I seem to remember somebody here saying that the prewash water from Tech Pan, I think, came out *black*, which seems like it would be pretty startling.

Why is there so much variation in these dyes? It seems like they have a pretty simple job, and I'm kind of surprised there isn't a single obvious Right Way To Do It.

-NT

I think you're putting too much weight on it. Is it really that important how deep is the color of the dye? They all do the same job and they leave naturally when the film is processed. That's all. The only variation in color I've noticed is depending on the amount of film I develop at once, since the ratio of dye and water increases thus making the final liquid darker.

Philippe-Georges · Jul 7, 2008

arigram said:
I think you're putting too much weight on it. Is it really that important how deep is the color of the dye? .

Important? Yes it is! It brings a little colour in the black an white .

Philippe

John Weinland · Sep 28, 2008

B&W film has not ever shown colored prewet effluent for me - always clear. Color film does, and I've noticed that doubling the prewet time deepens the color, changes the hue from blue to blue-green, and seems to greatly lower the overall saturation of the dried negative material. Unicolor K2 specifies a prewet step but others don't. I think more is going on than prewet there. My next rolls will skip the prewet.

Blue Color in Pre-wash of Film

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