120 B&W neg with yellow stain

[tedr1]

I have a set of nine B&W 120 neg strips, each strip is the full roll uncut, it is HP5+. The exposure and processing were normal and eight out of the nine are fine, however there is a staining problem with half of one strip, the first four frames have a yellow stain affecting the whole image area, all tones are affected, the film base is clear, further down the same strip the last five frames are unaffected. I have previously tried to clear this stain by refixing and washing but the although the stain was reduced initially, over time it has returned again (the negs are hanging in a set in daylight, eight strips are unaffected). I will soon be ready to print from these negs and wish to eliminate the yellow stain, I think it is going to mess with variable contrast exposures. Any suggestions what can be done?

 

[Ian Grant]

Sound like Dichroic fogging, caused by developer carry over in the emulsion into the fixing stage. This can be caused by Alkaline fixer aor a fixer that's turned alkaline due to no stop-bath, exhausted stop-bath or insufficient rinsing.

Ian

 

[tedr1]

Thank you. Can you recommend a remedy please?

 

[Ian Grant]

Thank you. Can you recommend a remedy please?

There isn't one really, sometimes a good soak in strong fixer may help. With prints books used to suggest a permanganate re-halogenationg bleach followed by a clearing bath and redevelopment.

You're probably better to just try and print through it and make sure you take steps to eliminate it happening again. If you use an alkaline stop bath you must use a stop bath with films and papers.

Ian

 

[Neil Grant]

Thank you. Can you recommend a remedy please?

You could try fixing it again to see if the yellow stain is residual emulsion. In my experience dichroic fog is usually purple - but maybe that's due to the films I've used. Make sure you agitate when going into the fix. Don't just 'dump' the film in it.

 

[R.Gould]

In my Early photo days, before I learn't better. I had this happen to some films, I believe it was caused by problems with the fixer, overused, and film not fixed for long enough, the film looked fine when first hung to dry, but went yellow after a while, I tried re fixing to no avail, nothing worked, I just had to print the yellow negative,
Richard

 

[Xmas]

In my Early photo days, before I learn't better. I had this happen to some films, I believe it was caused by problems with the fixer, overused, and film not fixed for long enough, the film looked fine when first hung to dry, but went yellow after a while, I tried re fixing to no avail, nothing worked, I just had to print the yellow negative,
Richard

Fixing is most critical.
It is film type, time, temperature, agitation and fixer exhaustion dependent.

If you use acid stop it is safe to fix in daylight for at least the time it took to clear the milky effect on the film all over again.

If you don't do this and you under fix or don't wash enough which is time, temperature, and agitation dependent, you gonna be sorry.

Development is less critical...

 

[R.Gould]

Fixing is most critical.
It is film type, time, temperature, agitation and fixer exhaustion dependent.

If you use acid stop it is safe to fix in daylight for at least the time it took to clear the milky effect on the film all over again.

If you don't do this and you under fix or don't wash enough which is time, temperature, and agitation dependent, you gonna be sorry.

Development is less critical...

I was a mere teenager, and then only just, I have an awful lot about the whole photographic process since then,especialy that using fixer for too long is false ecconamy, max for 600ml fixer at 1/4 is 7 films, then discard

 

[Gerald C Koch]

Dichroic fog is caused by dissolved silver being redeposited on the surface of the emulsion. It is usually identified by the fact that it appears to be a different color by reflected light than by transmitted light. Hence the name dichroic, meaning two colors. It can happen during development with high solvent developers like Microdol-X or during fixing with exhausted fixer. When noticed immediately it can be removed mechanically by rubbing the fingers on the film as it washes. Once the film dries removal is much harder. Sometimes briefly dipping the dry film in Farmer's reducer will help. The idea being to remove it from the surface before the reducer gets into the emulsion. Then a brief rinse, refixing and rewashing. A bit tricky but some claim it works.