Dichroic fog?

Hi there,

I sometimes read that using old developer formulas with modern films is the way to increase the risk of dichroic fog. Are today's film that different than the old ones or is dichroic fog an issue inherent to old developer formulas whatever the film used?

Take care.

Based on what I've read, it would seem that old formulas are less likely to cause it than exhausted developer or stop, or inadequate stop baths. It seems that this causes an increase in physical development of the silver and the staining dichroic fog.

I would imagine that I've oversimplified it, but at least it's a starting place.

hi dali

i got the dreaded green metalic fog by new developers + film not by using ye olde ones ..
it was contracted by NOT using kodak's tmax RS for sheet film ( tmx / tmy )
but instead using plain old kodak tmax developer ( this was in 1991 ).
i have no idea what the differences are between the 2 similar developers, or causes the fog and whatnot,
seeing some successfully use that developer + film/s and NOT gotten the fog .. ( even today ) ...

since the big K wasn't able to help me ( even with one of their own packaged products ? )
i contacted paul krott at sprint photo systems and he helped me dissolve it off, and refix it with KODAK's farmer's reducer ( but with sprint fixer ! ) .
the negatives were printable, but obviously the reducer thinned them out a little bit to get rid of the fog.

not for the weak of heart cause its trial and error if your negatives are thin / under developed you are kind of up the proverbial creek ...

john

In the 1960's newer versions of Kodak films were particularly susceptible to Dichroic fogg with DK-20 and Microdol leading to the introduction of Microdol-X, it seems that UK made versions may have been less prone as Kodak Ltd switched to Microdol-X much later.

I've used Ilford Delta 100 and Fomapan 100 & 200 in a developer that was essentially a hybrid of D-25 & Microdol both developers known prone to causing Dichroic fogging in the 60's and had no problems at all. Whether modern Kodak films would be OK I've no idea.

Ian

Any older formulas containing strong silver halide solvents such as either p-phenylenediamine or ortho-phentlenediamine are capable of producing dichroic fog.

Gerald C Koch said:

Any older formulas containing strong silver halide solvents such as either p-phenylenediamine or ortho-phentlenediamine are capable of producing dichroic fog.

Click to expand...

But then so were D-25, DK-20 and Microdol. Crawley in the 1960's stated Dichroic fog was a particular issue with the new generation of Kodak films. This was a time when Eastman Kodak had to treat their Gelatin because of the raised background radio-activity caused by the atom bomb tests I don't know if that had any impact.

Ian

D-25, DK-20 and Microdol are prime examples of developers that contain lots of solvent, or a very powerful one (DK-20). p-Phenylenediamine, on the other side, is not considered a Silver solvent, but may still be prone to physical development in conjunction with other solvents, e.g. Sulfite, and as a result be prone to cause dichroic fog.

I haven't seen dichroic fog with any new emulsion, even with PPD based developers, and even John's example is over 20 years old ...

jerry + ian ...

allegedly non RS tmax developer causes dfog with sheet film,
supposedly this may still be an issue, any clue what the differences between the rs and non rs developers are? the rs version was formulated for rotary systems , or replenishment systems
( that is what i was told, but i am gullible ) and maybe what makes the non rs version ineligible for replenishment or rotary systems and sheets makes it make fog with sheet film ?

thanks
john

To the list of offending chemicals sometimes added to developers can be added ammonia, amines in general, mercaptans, thiols like the amino acid cysteine, thiocyanate, and thiosulfate. In higher concentrations many of them have been used in monobaths. Grant Haist's Monobath Manual lists many such compounds.

"( that is what i was told, but i am gullible ) and maybe what makes the non rs version ineligible for replenishment or rotary systems and sheets makes it make fog with sheet film ?"

Good Morning, John,

I don't know the answer to your question, but, as I have posted in other threads on this subject, I have used the regular T-Max developer with sheet film for several decades. At first, I did it because I was too stupid to notice the bottle's warning label against such use, but I have never experienced the slightest problem, and I continue to get great results from the regular T-Max developer. My suspicion has always been that local water characteristics may account for the problems some have experienced, but that's strictly a guess.

Konical

hi konical

i wouldn't be surprised if you are right ... water supply
weird stuff ...

the funny thing is i had never gotten this fog before, or after ...
and i did process a handful of sheets as test sheets before i got the ones with fog ..
i was using it in a deep tank with hangers .. maybe THAT was my problem too ?


john

Rudeofus said:

D-25, DK-20 and Microdol are prime examples of developers that contain lots of solvent, or a very powerful one (DK-20). p-Phenylenediamine, on the other side, is not considered a Silver solvent, but may still be prone to physical development in conjunction with other solvents, e.g. Sulfite, and as a result be prone to cause dichroic fog.

I haven't seen dichroic fog with any new emulsion, even with PPD based developers, and even John's example is over 20 years old ...

Click to expand...

I don't have access to my copies of Mason, Glafkides, ... but Haist in the Monbath Manual p 28 says "Considerable loss of film emulsion speeds normally obtained, probably due in part to the solvent action of para-aminophenylene upon silver halide during the long times of development." Ortho-phenylenediamine has so little developer activity that its use in developers is only for its solvent action.

Very early developers used Ammonia as both a solvent and as an alkali. This caused dichroic fog! Lots of it!

Now, as for PPDs, it must be remembered that they were all sold as salts. All of the early ones were sold as salts of HCl and thus added a solvent to the developer in the form of NaCl. This was a low level but could cause some dichroic fog. But, the big clinker was that the old timers used PPD. Today's PPDs are blocked on both amine groups to prevent silver halide solvent action. So, N,N Diethy PPD is blocked on one group and N, N Diethy, 3 Methyl PPD is blocked fully on one group and hindered on the other group.

This chemical magic thus prevents modern CD2, CD3, CD4 and CD6 from acting as a silver solvent, and in addition they are supplied as salts of Sulfuric Acid or p-Toluene Sulfonic Acid. Thus there is no HCl added to the mix.

PE