Removing brown tone from reversal processed b&w?

johnielvis · Jun 21, 2013

Has the remedy for the brown tone been found? Or does it remain and require a change in development technique? Did the color bleach work? Did it do anything? What happened. Curious!

johnielvis · Jun 25, 2013

well I guess it's a secret then....

I've just discovered that when using ilford digital silver paper as a reversal that the brown tone appears in the re-development phase--if you leave it in the second developer past when the image is fully developed, first some dark silver fog gets developed...not much...then the highlights start to become more and more brown.

Therefore, it may be a function of second developer time--the best way around this is to develop by inspection to max dmax and then stop the second development and fix. This works for the ilford paper and may be why it's so elusive--for some it's more apparent--those with more highlights--where those with less highlights, the tone isn't so apparent.

johnielvis · Jun 26, 2013

I suspected fog and that's exactly what it was. A bit of weak ferricyanide bleach/fix and BAM..CLEAN CLEAR BRIGHT--and cleaned up that bit of dark silver too.

I checked back at my tests--pure white the first few...then I took a break..the older the paper sat in the holders, the more brown it got and eventually started getting black silver. It is fog. It is just way more apparent on the very white paper when it goes from pure white to brown--it's more difficult to see with a transparency for me.

Anyways--did anyone else even TRY to do a post bleach to see--it was very quick to remove that brown stuff---very very quick...the regular image was unaffected.

I used 2g/l of ferricyanide plus pure hypo fix mixed 1:1. it cleared to bright in less than half a minute--and this is very very weak bleach.

I'm convinced now that any "brown stain" that seems to have been "caused" by the second developer is, in reality, very fine developed silver that the developer is getting to.

give it a try--take the brown results and give it a bleach and watch what happens.

dr5chrome · Jun 29, 2013

Developers -

p-amino phenol hydrochloride, which is the main developing agent in rodinal, tends to have this brown color in the final image. There are several important factors when it comes to final image color. Even a new agent from another factory can cause color-tone shift. Other things as simple as the water you use +++, etc.. The best neutral result "with the developers used": I would stick to a developer [1st & 2nd] with a high concentrate of HQ and sulfite. Most films will have a good 'neutral' with such a developer.

dw

dr5.com

Tofek · Jun 30, 2013

Why does the developing agent stay on the film, after developing/fixing/rinsing ?

johnielvis · Jun 30, 2013

Interesting. I may just get some rodinal and try to get the brown tone just to see what the "rodinal brown" looks like compared to the "leftover silver brown" that I get. So the rodinal brown is down "to the root" of the reversal image then and cannot be "cleaned up" with a post bleach?

johnielvis · Jul 1, 2013

oh well--I guess our mr datsun has found his solution and now will guard it as one of his secrets of his secret process....

Rudeofus · Jul 1, 2013

There are multiple sources of brown in an emulsion: it could be brown stain (think pyro developers), it could be some form of fog, or it could be tiny silver crystals which carry important image information. A bleach will get rid of brown image in the latter two, but in the last case you don't really want to. Since DR5 suggested that Rodinal is no good for reversal development, I suggest everybody follow his advice and look at more suitable developers for B&W reversal. I don't think many here can match DR5's practical experience with b&w reversal ...

johnielvis · Jul 1, 2013

Nobody's explained how rodinal doesn't produce a brown image when used normally but only in reversal--what is the mechanism? it seem to me that there's nothing added in the silver that is causing a different chemical reaction. An ingredient was identified, but it was not explained as to how it only would affect the second development. So that appears to be nothing more than speculation...also--the subject is removing it--is it impossible to remove? There's a way to do everything.

Rudeofus · Jul 2, 2013

I can hardly blame DR5 for not giving away his trade secrets, quite to the contrary, I'm impressed he responded here at all.

I do have a theory about Rodinal and brown silver: in the FD step you have a strong solvent which completely removes tiny grains but leaves not so tiny grains behind as tiny grains. Tiny grains would normally either

not develop at all because they are very insensitive to light
be dissolved away by any moderately solvent developer

Now all of a sudden we have a strong re-exposure step which makes sure these tiny grains are exposed and will develop, too, and we have a more or less non-solvent developer (Rodinal) which happily develops them into tiny (and therefore brown) Silver crystals. DR5's suggestion to use a developer high in HQ (i.e. high contrast, i.e. won't develop tiny grains) and high in Sulfite (i.e. dissolves tiny grains before they develop) would certainly point in that direction.

johnielvis · Jul 2, 2013

I doubt explaining the mechanism of why something produces brown is giving away any secrets. I suspect it's all due to small silver particles too.

right--I think it's teeny developed grains too--or physically deposited teeny silver particles...

so it should be easily removed with a post ferricyanide bleaching step....as I suspected.

I just want to know if the bleaching worked--the original poster seems to want to keep quiet on this. It would be nice to confirm my suspicions. However, the silence may also speak volumes as well...

bluh....done with this booyah

mr.datsun · Jul 2, 2013

johnielvis said:
I doubt explaining the mechanism of why something produces brown is giving away any secrets. I suspect it's all due to small silver particles too.

right--I think it's teeny developed grains too--or physically deposited teeny silver particles...

so it should be easily removed with a post ferricyanide bleaching step....as I suspected.

I just want to know if the bleaching worked--the original poster seems to want to keep quiet on this. It would be nice to confirm my suspicions. However, the silence may also speak volumes as well...

bluh....done with this booyah

johnielvis. I'm not keeping quiet - I just haven't been able to do any work on developing recently. In the meantime, I'm spending what time I have on another aspect of my project . So I just do not have an answer. With regards the E6 bleach idea, I'm reluctant to go out and buy a whole E6 kit for this one test.

You're theory on the length of time of the 2nd dev is interesting - have you confirmed it?

dr5chrome · Jul 3, 2013

dr5

..not to despair. We are working on a possible "dr5-kit". Other than those close to the lab, this is the 1st It is mentioned here. If it's feasible, it might happen. dw

Rudeofus said:
I can hardly blame DR5 for not giving away his trade secrets, quite to the contrary, I'm impressed he responded here at all.

I do have a theory about Rodinal and brown silver: in the FD step you have a strong solvent which completely removes tiny grains but leaves not so tiny grains behind as tiny grains. Tiny grains would normally either

not develop at all because they are very insensitive to light

be dissolved away by any moderately solvent developer

Now all of a sudden we have a strong re-exposure step which makes sure these tiny grains are exposed and will develop, too, and we have a more or less non-solvent developer (Rodinal) which happily develops them into tiny (and therefore brown) Silver crystals. DR5's suggestion to use a developer high in HQ (i.e. high contrast, i.e. won't develop tiny grains) and high in Sulfite (i.e. dissolves tiny grains before they develop) would certainly point in that direction.

Rudeofus · Jul 3, 2013

dr5chrome said:
..not to despair. We are working on a possible "dr5-kit". Other than those close to the lab, this is the 1st It is mentioned here. If it's feasible, it might happen. dw

If this kit will resemble the Foma reversal kit in any way, please supply it with instructions that say: "Undissolved Permanganate grains in the bleach will leave ugly brown spots on your slides. Permanganate takes forever to dissolve, so please plan accordingly when you prepare the bathes."

mr.datsun · Jul 3, 2013

dr5chrome said:
p-amino phenol hydrochloride, which is the main developing agent in rodinal, tends to have this brown color in the final image. There are several important factors when it comes to final image color. Even a new agent from another factory can cause color-tone shift. Other things as simple as the water you use +++, etc.. The best neutral result "with the developers used": I would stick to a developer [1st & 2nd] with a high concentrate of HQ and sulfite. Most films will have a good 'neutral' with such a developer.

dw

dr5.com

Thanks for this explanation. I didn't notice it before.

The reason I was interested in R09 as a developer was that it appeared to be even more active than the Dokumol that I had been using. With it, I could reduce the amount of hypo needed to get similar results to the Dokumol with 4x the hypo . So, with R09, I felt was getting a bit closer to the 'dream' of a silver-solvent free 1st dev. And that is something I believe that you have achieved at dr5 - even though no one knows how.

And so, to answer your second post I, for one, would be interested in a dr5 home kit.

Tofek · Jul 3, 2013

I'd be quite interested too !

richyd · Jul 8, 2013

Funnily enough after some successful reversal processing I started getting yellowy/brown images since reading this thread. This was occurred both with second exposure and development and with chemical reversal. At first I thought it was the bleach and/or clear as it was getting a bit old but on renewing that, same result. This pointed to the first developer, I use Suprol, and the bottle had been open for quite a while. With fresh developer, the tint went away. But, what is interesting is that with slightly oxidised first developer I was even getting the stain with chemical reversal (using "Iron Out", not using that developer.

Thanks, for the tip on the ferricyanide bleach/fix, johnie, I wasn't clear on the recipe 'pure hypo 1:1' seems a low dilution , i.e. strong concentration of hypo, but I added the ferricynaide to my usual solution of hypo and it did brightened up the images on the the strips I tried.

johnielvis · Jul 8, 2013

hmmmm. so it could be that the brown color can be caused by a first developer that is not quite up to snuff and can't get some of the stuff on the first go-round that should have been bleached away--these then get developed in the second development after the super-reexposure step--a very fresh strong first developer leaves less brown. Bleach takes it away is the key. I'm starting to suspect that the rodinal keeping properties may not be as good as some may think--perhaps even rodinal decays like all the others and results in the final brown. If the rodinal brown is removed by bleach, then this is probably what is going on and not some bizarre reaction with a certain component. If the component causes brown on development, then people's negatives developed with rodinal should be brown too, but they're not--that's why I don't think it's a component reaction but more a result of left over silver that should have got developed in the first go.

Also--if there is brown being left over with a hypo developer, then the hypo isn't doing it's job then--or there's not enough of it to do it's job OR the developer isn't strong enough.

I hope somebody takes a rodinal brown positiive and trys the ferricyanide to see if it clears it.

Removing brown tone from reversal processed b&w?

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