Reversal Process - Experiences and Questions - 2nd Exposure and Development, Film Speed Changes

I've been working towards making black and white slides recently. After some trial and error, I've managed to get a couple of usable slides, but would like to improve the process further.


This is a photograph from the test roll with the levels stretched to fill the contrast range.

The film was Kentmere 100 shot at box speed. I used D-76 stock without hypo as both the first and second developer. The bleach is equal parts 2g/l potassium permanganate and 1% sulphuric acid. This is half the concentration recommended by Ilford, but after reading suggestions that the stronger potassium permanganate bleach could damage the film emulsion, I decided to dilute the bleach and extend bleaching time to compensate.

First development was for 21 minutes, continuous agitation for the first minute and one inversion each minute thereafter. 9 minutes is the starting point for negatives in this developer, so 21 minutes must represent a one or two stop push. After trialling 14 minutes as a developing time, 21 minutes gave a slide that was much brighter for projection.

Bleaching was continued for 16 minutes with continuous agitation, to be certain of removing all the developed silver. A shorter time may have been sufficient, but the extended time did not appear to harm the emulsion. Re-exposure was for one minute on each side, 30cm from a fluorescent light tube. Re-development was continued for 16 minutes with frequent agitation.

In full room light, I cut the film into single frames for fixing individually in a measuring cylinder. The first frame was in the fixer for less than a minute when I noticed a reduction in density around the perforations. I redeveloped subsequent frames for 5 and then 10 minutes, again in stock D-76. Only after 10 minutes of re-development did the image stay on the film, clearing slightly after 2 minutes in the fixer. It's hard to say whether the fogging exposure or the second development was insufficient, causing the removal of the image by the fixer, or perhaps both were insufficient. The film was exposed to normal room light for a long time after re-development for the first time and re-development for the second time without any ill effects, so I suspect that increasing the second exposure to a much longer time would be fine.

On examining the slides that I have so far, the brightness is good. Although there is detail in the shadows and highlights, can the contrast be increased? I have a feeling, as the first development takes 21 minutes, that ISO 100 is the wrong speed for the film in reversal. Can shooting at, say, ISO 50 and reducing the development time give better contrast? Or should a different developer be used specifically to increase the contrast?

I look forward to hearing your suggestions, especially on film speed and which part of the process to change next.

Contrast and brightness are controlled by first developer, whereas all other process steps are meant to run to completion. Second, whatever is dark after first developer, will be bright after process completion and vice versa. Once you understand this, you know what to do when you want to change the appearance of your slides:

1. If slide contrast is too low, then you need to extend development in first developer. If contrast is too high, then first development needs to be decreased.
2. If contrast is ok but the highlights are too dark, then either exposure is too low, or first developer is too weak (too dilute, shows exhaustion)
3. If contrast is ok but the shadows are too bright, then either exposure is too high, or first developer is foggy.

Note, that a first developer may well become too foggy for reversal processing, even if it is not foggy for regular B&W development, since first development is typically much stronger than regular B&W development. Since first development is very strong (would be considered a massive push for regular B&W development), some B&W films give higher speed with reversal processing, compare e.g. Adox Silvermax 100 with Adox Scala 160 (allegedly the same emulsion).

I don't know how many times this has to be said. Follow Ilford's instructions to the letter. Do not make changes to the chemistry or times. (Particularly do not make changes because of what you imagine might happen.) Once you can consistently get good slides THEN you might consider making small adjusts ONE AT A TIME. Do not attempt to vary more than one parameter at a time.

Rudeofus said:

1. If slide contrast is too low, then you need to extend development in first developer. If contrast is too high, then first development needs to be decreased.
2. If contrast is ok but the highlights are too dark, then either exposure is too low, or first developer is too weak (too dilute, shows exhaustion)
3. If contrast is ok but the shadows are too bright, then either exposure is too high, or first developer is foggy.

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Thank you for this advice. Assessing the film again, I think the problem is mainly the shadows being too bright. Highlights have gone to almost the same density as the unexposed end of a negative processed roll, but still show a good amount of detail. With colour slides, I'd expect there to be a complete loss of detail in overexposed areas. Is the same true of black and white film when reversed?

Platelayer said:

The film was Kentmere 100 shot at box speed. I used D-76 stock without hypo as both the first and second developer.

(...) The bleach is equal parts 2g/l potassium permanganate and 1% sulphuric acid. This is half the concentration recommended by Ilford
(...)
First development was for 21 minutes, (...)

(...)can the contrast be increased? I have a feeling, as the first development takes 21 minutes, that ISO 100 is the wrong speed for the film in reversal.

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In my humble opinion,

Almost all the times reversal is done, the first developer is chosen to be a developer that gives HIGH contast, aka a "contrast working developer". D76 is far from such a developer. Your first development time is very long because D76 is a developer for normal contrast with good compensating properties, which prevents contrast from going too high. Slides are to be developed to a contrast index way, way higher than negatives.

So i'd suggest using other first developer.

Bleach: Why did you not use Ilford's recommendation? If the bleach doesn't work fully, they you would not get the clearest highlights. Perhaps you're (wrongly) blaming the film's speed on what appears to be a problem with your first developer and bleach.

For second developer you need to develop to completion and here also a strong developer would help.

Platelayer said:

Assessing the film again, I think the problem is mainly the shadows being too bright.

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Make sure the film gets enough light at the reexposure. And of course, that 2nd developer is strong to work to completion.

flavio81 said:

In my humble opinion,

Almost all the times reversal is done, the first developer is chosen to be a developer that gives HIGH contast, aka a "contrast working developer". D76 is far from such a developer. Your first development time is very long because D76 is a developer for normal contrast with good compensating properties, which prevents contrast from going too high. Slides are to be developed to a contrast index way, way higher than negatives.

So i'd suggest using other first developer.

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Thanks, changing the developer and rating the film at a faster speed both sound like good ideas - but not at the same time. Although Ilford suggest PQ Universal developer, would a speed increasing developer such as Microphen give more contrast while reducing development time? The Digital Truth chart suggests adding 30 seconds to the time for Kentmere 100 to give a one stop push (up to 9 minutes from 8:30).

I don't think the bleach is a problem here; the highlights look as clear as the film base, but I'm surprised at the amount of detail they contain after the shadows appear to be over exposed.

Once again, follow Ilford's recommendations. Film speed and contrast are determined by the time in the first developer. Using a speed increasing developer just adds another variable to the mix.

BTW take what Digital Truth posts with a grain of salt. Their site is not reviewed for accuracy.

Platelayer said:

Thanks, changing the developer and rating the film at a faster speed both sound like good ideas - but not at the same time. Although Ilford suggest PQ Universal developer, would a speed increasing developer such as Microphen give more contrast while reducing development time?

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Platelayer,

For reversal process you need a CONTRAST WORKING DEVELOPER (emphasis added here). This is a developer that used in normal circumstances (ex. for developing negative film) would create a crazy high contrast image. A paper developer (i.e. Dektol) gets close to such a developer. Ideally, you would also want the first developer to be a low fog developer.

Microphen is not such a developer. Microphen is a "normal contrast, speed-enhancing" developer suitable for pushing, nothing more nothing less. Please do not consider what you are doing (on the first development) as "push development", because we want the first developer to pump up the contrast even more.

PQ Universal is in reality a paper developer which, if you diminish its strength, is suitable for developing negative film as well. I think the Ilford recommendation will make you use PQ Universal in the strength normally used for developing PAPER. This is good because you want to make PQ Univeral work HARD and give HARD contrast.

An alternative to PQ Universal would be Foma Universal Developer.

BTW, take a look at this PDF, it explains everything you want to know
http://www.ars-imago.com/productinfos/osbahr_reversal_films.pdf

from that PDF, regarding First Developer:

In general, every negative or paper developer can be used. It just needs to be
concentrated enough. A good illustration of this is the fact that Agfa Rodinal
is typically used at development times roughly comparable to this recipe at
1:25 dilution, but here it is used at dilution stronger than 1:10, which would
be the recommended application of Rodinal as a paper developer.
(...)

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Other suitable developers for 'first developer' are:
Kodak D-19 -- Kodak's official first developer for reversal processing of black and white motion picture film.
Kodak D-168
Kodak D-67
Kodak D-94 (D-19 plus some silver halide solvent)
Rodinal (see PDF link)
Dektol
Foma Universal
Orwo 829 -- Orwo's official first developer for B/W motion reversal film, see pdf:
http://www.filmotec.de/wp-content/uploads/2010/08/V-I-VV-4185-e.pdf

Platelayer said:

Thank you for this advice. Assessing the film again, I think the problem is mainly the shadows being too bright. Highlights have gone to almost the same density as the unexposed end of a negative processed roll, but still show a good amount of detail. With colour slides, I'd expect there to be a complete loss of detail in overexposed areas. Is the same true of black and white film when reversed?

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There are some differences between color reversal and black&white reversal, but as far as first developer is concerned, they are quite similar. I interpret your above statement as "contrast is fine, highlights are ok but shadows are weak", which means you should add restrainer to your first developer. I recommend starting with 0.5 g/l Potassium Bromide increments until the shadows are where you want them, then adjust first developer time to get the highlights where you want them.

About exposure: remember that the shadow region of a reversal image represents the toe region of a negative. If you underexpose, detail will get lost in toe region, which translates into lost detail in the shadow region of your slides. Overexposure, on the other side, can be easily compensated for by reducing first development, which means it only becomes apparent if contrast turns out too weak for your taste.

Until a baseline is established using an unmodified Ilford process, changes like adding potassium bromide or adjusting the amount of thiosulfate should not be made. I don't believe that the OP has done this. Until he does this I really don't know what help can be offered. Ilford makes no mention of adding bromide so I would recommend that after a baseline is established to try adjusting the thiosulfate amount in the first developer.

I would also suggest contacting Ilford for help.

flavio81 said:

Microphen is not such a developer. Microphen is a "normal contrast, speed-enhancing" developer suitable for pushing, nothing more nothing less. Please do not consider what you are doing (on the first development) as "push development", because we want the first developer to pump up the contrast even more.

PQ Universal is in reality a paper developer which, if you diminish its strength, is suitable for developing negative film as well. I think the Ilford recommendation will make you use PQ Universal in the strength normally used for developing PAPER. This is good because you want to make PQ Univeral work HARD and give HARD contrast.

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I was not aware of the distinction between a contrast working developer and a speed increasing developer. I will get hold of one of these developers, it looks like Ilford PQ is availble locally, and try that. Really, I'm surprised that just a little experimentation has gotten me this far already. A couple of images from the first roll make good slides, so I'm keen to make incremental rather than sweeping changes - changing the film speed, developer, and I'll see how the later images compare to the ones I have now.

Alessandro Serrao said:

Did anyone try the Orwo process?

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I used the ORWO process for several years to develop my 16mm film. Found it to be an alrounder that worked well with the following 16mm ORWO UN54, Foma R100, Kodak 7266 films. Also had success with most b&w 35mm and 120 films. What was interesting was the results of developing old color negative cine film as b&w reversal. I over exposed by some stops to get good contrast to counter the age of the film. These projected results were excellent and your eyes forget about orange cast in the white areas very quickly. My only anoyance was the color neg film exhausted the developer much faster and I had the remjet to deal with.

I stopped using ORWO process and moved to Tetenal Eukobrom as it is less time consuming mixing up the chemistry.

Ive used a catechol staining developer (just catechol and sodium carbonate) as my second developer, and made very large gain to dMax making more stunning slides. After second developer appears complete use any other developer that you would have normally used as a second developer as a third developer, just to make sure development is to completion prior to fixing.

Also make sure you bleach clear before doing this and then wash out the sulphite properly.

Ive posted the best general purpose first developer Ive found here before, regardless, the staining dev as a second dev method gives real beauty to slides.

My favourite general purpose reversal first dev: (there was a url link here which no longer exists)

You'll need to adjust it a bit for Kentmere I think, T-Max of course would be better.

Also note that dev is unsuitable regardless of time for Fomapan R100. I made a separate suitable dev for that.

There are loads of threads on this which if you study am sure you will find something to fit your films, available chemistry and so on. It does take a lot if personal experimentation but you should get a good starting point by studying the posts. The reports and detailed processes people have actually used and the results are invaluable.

Start with
(there was a url link here which no longer exists)

at the bottom of page 2 there is a post that lists half a dozen or so other relevant threads.

Richard

I've been interested in making B&W positives and have read thru this process on Ilford's site as well other places. It seems fairly involved and cumbersome, as attested to by the postings here.

Obviously the best solution would be for someone to bring back a direct positive film. It seems that it would be quite popular, but I'm not holding my breath.

The other option is "contact printing" a negative onto film. Has anyone one tried both that and this developing process? It would be interesting to know how they compare.

thuggins said:

I've been interested in making B&W positives and have read thru this process on Ilford's site as well other places. It seems fairly involved and cumbersome, as attested to by the postings here.

Obviously the best solution would be for someone to bring back a direct positive film. It seems that it would be quite popular, but I'm not holding my breath.

The other option is "contact printing" a negative onto film. Has anyone one tried both that and this developing process? It would be interesting to know how they compare.

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The B&W reversal process is not particularly difficult. It is certainly easier than making color slides. It does require, like the color process, an attention to details.

The problem with printing from a negative is that you need a film designed to make positives. In other words a high contrast film with a clear, colorless base. There are several cine films but they are not usually available in small quantities. You might find someone selling short ends however. To get good registration you would have to devise a printing frame.

thuggins said:

I've been interested in making B&W positives and have read thru this process on Ilford's site as well other places. It seems fairly involved and cumbersome, as attested to by the postings here.

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I wouldn't call it too involved - even if you make a complete mess of the process, you're bound to get something decent out of it just by following the steps in order.

Thank you again for all the advice in this thread. I shot some more Kentmere 100 today, I'll let you know how I get on developing it with a different developer as soon as it's done. Eukobrom and Dektol are sold as 'print' developers alongside Ilford PQ - using any one of these might give better results.

I shot another roll at the weekend with the camera set at ISO 160 and paying close attention to the exposure throughout. I think this frame shows best what the change to the exposure did for this roll. The shadow tones are looking more natural, unlike the previous roll where they had became a bit washed out. It looks much better when projected with the deeper blacks.

Processing was the same as the previous roll - 21 minutes in D-76 for the first development. I'll hopefully be getting some Ilford PQ soon, I look forward to seeing what difference that makes. In any case, I look forward to development being a bit quicker.

In general, your first developer needs to be a HIGH contrast developer to get a good result in your final slide. D-76 or Perceptol are way too low in contrast to give a suitable contrast first negative. There must also be a silver solvent (ilford suggests Hypo, I use a Thiocyanate). Don't overdo the bleach time. I use a Chrome Alum stop between the first developer and the bleach which seems to help keep the emulsion intact with later steps. I also use a chromium bleach, not the permanganate. Second developer has to be an active developer (Dektol of Ilford Universal PQ) and the development has to go to completion tp get good full blacks. NO silver solvent in the second developer. The most salient issue in making direct positives is the choice of film. The best films are ones that have inherently higher contrast. I have found that Ilford PanF+ and Rollei RPX are excellent. Ilford D100 is passable. Someone has said that HP5+ reverses well, but I have not yet tested it. No such luck for me with fp4, tri-x, Cinestill xx, T-max, but that's just my experience. A clear film base is very important if you want to have a clear image for viewing or projecting. Hope this helps.