Can Kodak D76 be substituted for D94a by adding sodium thiosulphate?

Tofek · Feb 12, 2013

Ok I see, thank you. However, the silver that is reduced (developed) in the first development will actually be bleached. And the ''fog+non developed silver'' is then the part left for positive developing. So if some of the positive part is bleached away, you'll lose on final density. And you don't want that. Do I get it right ?

mr.datsun · Feb 12, 2013

I see your point. As the bleach is before any slight fogging might be taken care of by the clearing bath. Maybe you have to get it just right before fogging shows. Maybe a slight fogging is negligible in terms of the final result anyway, but I think the idea is to avoid it getting to that point if possible. Over to Mr Red, I think.

Photo Engineer · Feb 12, 2013

You have to recognize that in reversal processing, the first developer does not go to completion but the second developer does. Therefore, the first developer must have a tad of silver halide solvent in it to ensure that whites are white. To do this, a slight amount of fog is normally needed in the first developer to ensure that the second developer does not give gray whites.

There is still plenty of Silver Halide to get black blacks in the final positive.

PE

mrred · Feb 12, 2013

yes. You expect some fogging but too much will cause the bleach step to work too hard and effectively strip away the latent image thus reducing dynamic range. Not so much "pushing you off a development cliff" but more of a "no real gain" situation.

Photo Engineer · Feb 12, 2013

Mrred, not sure what you are talking about. The latent image is only used in the first developer. And, silver is silver as far as the bleach step is concerned. Any and all Silver metal is converted to Silver Sulfate which washes out. By the time the film hits the bleach, there is no latent image to be concerned about.

Fog is not related, in this instance, to latent image in the sense that you are forcing a silver halide solvent to cause physical development and concomitant fog, to allow an overall increase in density that then allows the clean out of the final white areas. Without the fog, caused by the solvent, the whites would be very gray in the final image.

Now, there are some developers that work without solvent action, but I am not going into that here.

PE

mr.datsun · Feb 12, 2013

Ok. I'm confused. But aside from that for the moment, I just spent two hours trying to get fog on Tri-X. I took my dev (PQ Universal mixed at 1+5) from 6m to 16m in 2 minute steps. (I normally have been using it for 10m). Nothing. No fog. Is the PQ dev not energetic enough? What's happening? Remember that Ilford recommended it at 1+5 10m for their FP4 film. Do I need to go all the way to 20mins, double the concentration, or go for Dektol?

mrred · Feb 12, 2013

Try 1:1 or 1:2. I don't use much less than this with Dektol which should have the same activity level. Even then it's at the suggested time of 12. Time is less critical than when developing negatives as the density is much greater. With D-19 I had to use 1:1 which was why I stopped using it; it got much more expensive than Dektol.

try jumping up more in times. I would use increments of 10. When you get fog, try backing off half way from the last point. If that is good, bump it forward half way....and so on.

You should get the similar results with PQ. It looks like you are just using a strong enough dilution. In theory you should be able to use any developer. Getting it to work well or with a reasonable cost is another story.

mrred · Feb 12, 2013

Photo Engineer said:
Mrred, not sure what you are talking about.

There was a PDF floating around, written by a apuger, about doing reversals with his twist on the theory. He indecated that the bleach step, if left too long, would also remove the silver in the image.

I will have to find that pdf....

I would guess you would have points based more on fact....

It's sad on how little current info there is on this, out there.

Photo Engineer · Feb 12, 2013

Guys;

Without reading all of this, why not use something that has been done before with good results?

PE

henry finley · Feb 13, 2013

I have watched this thread with some amount of interest. At the same time I'm bound to ask "why". What use is it? Or am I missing something? Are you guys actually professionals who have a market for the use of this process? Black and White 35mm slides you can mount and put in a carousel projector. Is there a market for this? If you are indeed doing this professionally, I would like to know much more about this. Keep it up. I'm sitting on the sidelines just learning.

mr.datsun · Feb 13, 2013

Photo Engineer said:
Guys;

Without reading all of this, why not use something that has been done before with good results?

PE

PE, you seem to know a lot about this and I'm always open to ideas.

To put this into context you have to remember that i'm going to be working with Tri-X Super 8. As far as I know the only known and documented developer is the Kodak one - D94(a). And we can't get this without mixing it from scratch which I just cannot do at home. All other developers I've come across are aimed at other films and usually with lower ASA ratings than the Tri-X which is down-rated to 160/200 ASA when used in Super 8.

As Mr Red says the information is scant. Especially workable and practical information. Much of what info there is out there, is based on what people have experimented with – and often unverified by peer group. It's partly an internet problem, it's partly that the old reliable off the shelf commercial solutions have long gone...

mr.datsun · Feb 13, 2013

mrred said:
Try 1:1 or 1:2. I don't use much less than this with Dektol which should have the same activity level. Even then it's at the suggested time of 12. Time is less critical than when developing negatives as the density is much greater. With D-19 I had to use 1:1 which was why I stopped using it; it got much more expensive than Dektol.

try jumping up more in times. I would use increments of 10. When you get fog, try backing off half way from the last point. If that is good, bump it forward half way....and so on.

You should get the similar results with PQ. It looks like you are just using a strong enough dilution. In theory you should be able to use any developer. Getting it to work well or with a reasonable cost is another story.

Mr Red. If as you say, then it's going to boil down to cost. Your Dektol is 3.8L of stock diluted at 1+1 or 1+2. If I dilute my 500ml bottle of PQ (similar cost) at 1+1 then it'll take a whole bottle to do one Super 8 Film at 1L (and that's only the 1st developer). So I'm going to try a bottle of Dektol in liquid form and then if the equivalent dilutions can be worked out I will compare costs between Dektol powdered and Dektol liquid. I think Dektol stock at 1+1 is the same as Dektol liquid at 1+9 but I'm not sure.

Photo Engineer · Feb 13, 2013

Well, there are some reversal kits out there, and there are also reversal process services. That is kind of what I was referring to. This would then be less of a problem I would think.

PE

mr.datsun · Feb 13, 2013

PE. There is one reversal kit out there*. It called the Foma Reversal kit. It's the one I am using and the developer in it is not energetic enough for Tri-X. that is the reason for my journeys into the unknown.

I need to process the film myself as it's an important part of my working method but also just because I get a lot of satisfaction from doing it myself.

*although Adox have announced one for their Pan-X Reverso Super 8 film (ie. Scala). We don't know when it will be available even if it did work with Tri-X.

Photo Engineer · Feb 13, 2013

Ah, and Kodak has apparently stopped making theirs.

Sorry.

PE

Tofek · Feb 13, 2013

mr.datsun said:
It called the Foma Reversal kit. It's the one I am using and the developer in it is not energetic enough for Tri-X.

Have you finally tried it ?

Photo Engineer · Feb 13, 2013

The Formulary sells a reversal kit modeled on the Kodak one. It is 01-0600. Should work with most any film.

PE

mr.datsun · Feb 13, 2013

Tofek said:
Have you finally tried it ?

Tofek. No, I was told it would be unsuccessful by two people. And I haven't tried it to confirm that. I guess it's the idea of spending days testing with no idea it will work. I'm trying the Kodak Dektol liquid version, POLYMAX soon and will post results - probably not until next week.

Have you thought about trying the Dokumol direction? I'm not clear what the economic cost of that one would be...

mr.datsun · Feb 13, 2013

Photo Engineer said:
The Formulary sells a reversal kit modeled on the Kodak one. It is 01-0600. Should work with most any film.

PE

PE. Thank-you. I haven't seen the Formulary's site before although I've heard of it.

But the Formulary's kit does say it's for TMAX 100 and 400 not Tri-X.

Kodak also make a TMAX reversal developer (KODAK T-MAX 100 Direct Positive Film Developing Outfit), too but it's only stated for TMAX and Technical Pan and that's why I decided to not to investigate it apart from seeing that someone had had no success with it on Tri-X (see below).

See doc:

http://wwwuk.kodak.com/global/en/professional/support/techPubs/j87/j87.pdf

Of course there's nothing saying that these TMAX reversal kits wont work and here's two conflicting reports that i found.

Ken Paul Rosenthal: 'The TMAX kit was designed for Plus-X and Tri-X black and white reversal stocks' . However Ken does not detail or show his B&W results, so I'm not going to take it as gospel.

and then:

aca91: 'I developed a super 8 roll of Tri-X with a Tmax Reversal Kit and got nothing from it'

of course, it's only one anecdote, and he could have just got something wrong.

It's interesting as, although I probably wont be able to get the Formulary kit in the UK, I might be able to get the Kodak one. So if it was known to work, it might be worth investigating.

Photo Engineer · Feb 13, 2013

I could not find that Kodak link. I guess they still make it.

Ok, I should tell you that the original kit was developed (pun unintended) for Tri-X and Plus x as well as Super XX and a few other films. It used a Dichromate bleach. The times were changed and a Permanganate bleach was then used for T-Max. Basically, the times and the bleach changes were the big items. IDK what bleach is now used, but I suspect Permanganate due to the toxicity claimed for the Dichromate bleach.

I have one of the older "universal" kits here and probably have the instructions as well. I'll take a look.

PE

Tofek · Feb 13, 2013

mr.datsun said:
Have you thought about trying the Dokumol direction? I'm not clear what the economic cost of that one would be...

Yes I tried the Dokumol direction last weekend. I used 1+9 dilution, first without KSCN and then with 5g/L of KSCN. The results are awesome, the contrast is very high, the blacks are beautiful. The KSCN helped to clear the highlights without touching (surprisingly!) the shadows, so it increased contrast a little, which I didn't really expect...So the density is great and the film pretty bright. I can take a photo of how the film looks this weekend, if you want. I'll definitely stick with Dokumol and play with dilutions (dilute more) and use of KSCN.

mr.datsun · Feb 13, 2013

Tofek said:
Yes I tried the Dokumol direction last weekend. I used 1+9 dilution, first without KSCN and then with 5g/L of KSCN. The results are awesome, the contrast is very high, the blacks are beautiful. The KSCN helped to clear the highlights without touching (surprisingly!) the shadows, so it increased contrast a little, which I didn't really expect...So the density is great and the film pretty bright. I can take a photo of how the film looks this weekend, if you want. I'll definitely stick with Dokumol and play with dilutions (dilute more) and use of KSCN.

Tofek. You sound happy! YEs, I'd love to see the results, please. Which film stock are you testing on?

Tofek · Feb 14, 2013

I'm still using Orwo UN54, a rather low contrast 100ASA stock. But I will soon change for Fomapan R100, a true reversal stock with clear base. It should ship today...

Can Kodak D76 be substituted for D94a by adding sodium thiosulphate?

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