How to (consistently) make positive E-6 transparencies with C-41 chemicals

Osmdesat said:

Perhaps he meant potassium thiocyanate (rhodanide), which is added to the FDs to boost up shadows and lights. This chemical really fogs the emulsion. I don't know exact reaction, but probably it directly builds up silver from silver halides in both exposed (less) and unexposed areas (more), which lifts up and flattens the resulting curve.

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I am surprised by this claim about thiocyanate. As far as I know, it is simply a powerful silver solvent - similar to hypo, but much more energetic. Or in the ranking - DTOD, thiocyanate, thiosulfate, chloride. For the first three solvents (chloride is too slow a solvent) there is a claim that added in small quantities to the black and white developer, they will stimulate development for some reason, while at the same time clearing the tones.

lamerko said:

I am surprised by this claim about thiocyanate. As far as I know, it is simply a powerful silver solvent - similar to hypo, but much more energetic. Or in the ranking - DTOD, thiocyanate, thiosulfate, chloride. For the first three solvents (chloride is too slow a solvent) there is a claim that added in small quantities to the black and white developer, they will stimulate development for some reason, while at the same time clearing the tones.

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I may be wrong. Because I observed that emulsion gets dark even in unexposed areas with thiocyanate added, my assumption was that it builds up silver there and thus fogs the film. But maybe there's something else going on...

Are you perhaps mistaking thiourea for thiocyanate?

From looking at my experiments with different E-6 FD formulas, I would dare call Thiocyanate some kind of minus bromide compound. While bromide or other restrainers restrict fog and to some extent contrast, strong solvents seem to do the exact opposite, i.e. they simply make the developer more active.

Thiourea is yet another animal, it is both a solvent and at alkaline pH a powerful fogging agent.

Hello, After looking for informations about RA-4 positive printing, I just thought I could give a try at the same process with E-6 films.

So I shot a few different very expired films (EPN, EPY, RAP, RTP) at ISO 20, with a Super-Angulon 4,5/75, 1 s at f:22

Developpement in a Jobo rotating drum (tank system 3010 for 10 4 x 5 " sheets)

- water soak 20 ° C (sorry for my french accent with mesures, hopefully, time measurement is the same all around the world ;o) 3 mn
- Adox X-T3 (similar to Kodak X-Tol but way easier to mix !) 1 + 1 at 20 ° C for 10 mn (I didn't come here first, just wanted to try something I didn't know if it was possible)
- Stop 30 s
- wash and light exposure (with a 180 W 5300 LED at 1 m) for a few minutes
- Fuji C-41 kit for the color process, at 38 ° (inbox instructions) CD, Bleach, Fix, Wash, Stab
bad phone scan (The emerald one, a Fujichrome Astia I dumbly managed to put behind another film in the tank, so it's not been really developped ;^)


I was already very happy with that result (I knew now it was possible), of course it looked underexposed and maybe had some color cast, and fog from cosmic particules, so I came here to have a look.

And for the second attempt, same exposure (but not the same day), all with the same film (EPN) and different developping times (it was a real mess to open the tank to extract one film and put it in the stop bath and put the lid again to develop some more time, five times, I had the hands full of developper and stop bath, and no, I don't think it's possible to pick a developper soaked film in those tanks in the dark with gloves on)

- soak water at 38 ° C for 3 mn
- Adox XT-3 dev, stock à 38 °, with added 6 drops of Benzotriazole (at 1 g / L) for the cosmic rays fog for from about 7 mn to 13 mn (I'm not very precise on the times, as I was messing around the lab with my hands full of 38 ° slippy chemicals)
- for the remaining steps, same as before, except I did the light fogging outside of water and there are some artefacts on some images due to some water drops on the film :


The new ones are the blue ones, I put the first attempts on the side to compare.
I have numbered (roman style) the new ones during the light exposure sequence, engraving the emulsion side with a sharp thing, but I think I got wrong, as the N° II seems to be the darker one, it should be inverted with the N° I
So, it looks like I'm overexposed, it's normal after all, the scene is very contrasted, there's about 10 or 11 stops of difference between the darkest spot and the clouds and to have a good exposure on the crane, I should have closed to f:45 and not F:22.
Next, I'll try to set the ISO at 50 and add some thiocyanate or thiosufate in the dev to see if it changes something, and a more colourful and not so contrasted image.

New tests, with one stop more exposed films, from ISO 20 to ISO 50 :

Fujichrome Astia RAP Exp 08/2003

Kodak Ektachrome EPN exp 09/2003 (I think opened since a too long time, those 50 sheets boxes must be quickly shot after opening)

Fujichrome Provia RDP III exp 08/2004

dev : XT-3 stock + 6 drops of Benzotriazole + a pinch of sodium thiosulfate at 38 ° C for 7 mn 30 sec

Everything else same as previously mentioned : stop, wash, light fogging with an 5300 K 180 w LED, C41 dev, bleach, wash, fix, wash and stab, all at 38 ° C

Too clear, looks overexposed

then the same shots developed with the same developper and additives for 9 mn 30 sec, I wanted to be sure that more development was more clear (that was not clear in my mind ;^)

Still overexposed, and more contrasted, I'm just pushing the films.

I couldn’t manage to edit the one by one shots (it’s very similar and somehow very different) so here are the same picture with the two developing times, four by four, no colour editing, Olympus EM5 + 60 Macro (it's inside Panodia P45 protecting sleeves so, maybe not the best scans I've made) :









On the right side, the two last are sandwiches of very overexposed EPN, two on top, maybe four down, it gives some kind of 3 D.

Another attempt with a less active developer (400 ml dev + 300 ml water) and the same additives, the colour cast is different (except for the EPN) and 2 more stops closed, it’s less overexposed… better.





And 2 different 120 films, an Kodak 160 T EPT exp 07/2002 and an unknown date Fujichrome Provia 100 (RDP II is old) had been tried, developed in the same tank as the 4 x 5’’ more successful one :



Unfiltered tungsten film in daylight is always...



Pinkish haze, pinkish HAAAZE !

A fast and dirty light and contrast edit of the cat that's living around the house (the slide is as tiny as the one above, but with a magnifier on the light-table, it's beautiful ):


8 seconds at f:8, Apo-Symmar 240:5,6 with a lot of tilt front and back, the kitten's lying on a bed that's dark blue !

Ok, the developper is still too strong or too long. I’ll try next with an 1 + 1 dilution and some drops of Rodinal or HC-110 part A sirup, and less time.

And of course I have to try the RA-4 colour dev thing.

And I could try, to have an idea, some E6 FD found in a closet, without the rest of the kit (salvaged for the blix ;o), maybe some drops of pure one in the XT-3 !

Anyway, colour cross processing gives a cast to the film that’s very variable depending on the film base itself and of course, the age is an important factor. I’ve done that hundreds if not thousands times with E-6 films developed in C-41, Velvia, Astia and Fujichrome MS 100/1000 has the emerald green mask (the MS 100/1000 is more cyan), Ektachrome 100 SW is very magenta, Tungsten films all tend do have a yellow mask (guess why ;o) and some Agfa and Konica films give a very deep blue mask (nearly impossible to see thru), more modern emulsions are much more flat, like Fujichrome Sensia and Provia (same film and Agfa Precisa CT that’s also the exactly the same) with a slight purple base and Kodak Ectachrome 100 G, and the new 100 E also with a completely clear transparent base.

So the quest for a perfect colour rendition is not my goal, I just want to be able to use those films in positive with a good result enough, and I kinda like the results so far, I’m getting a nice new palette of colours, still a little dull (I'm a Velvia fanboy so, not used to pastel colours).



And it’s more convenient (and fast, and cheaper) to have the positive directly, as I’m used to shoot again my negatives with the same process to have a positive !

Another test, same films as before but the EPN box's empty and there's now some EPR ( Ektachrome 64 daylight) replacing it.

First dev : Adox XT-3 1 + 1 at 38 C ° with added 12 drops of benzotriazole (for 800 ml of solution, I intended to make a second test just after the results of the first one, so my quantity is double) at 1 + 1, a pinch of sodium thiosulphate and 5 cl of pure HC 110 syrup, developing time 5 mn 30 (following steps all identical except for the light fogging, done with a dull LED for a long time).
Unedited Olympus EM-5 + 60 macro (colours are quite accurate but the Adox protecting sleeves are awfully not really clear)


The Kodak family liked a lot the HC-110 additive, it's a little under exposed but looks way better than before, and still quite blue.



Fuji family didn't like the HC-110 additive ! particularly the Astia



Even if underdeveloped the colours are not good, that's an obvious reason HC-110 isn't any good for Fuji films, that's why previous posts on the subject having tried only that FD said Fuji films don't stand well the thing.

So it needs more developing time, and just when I was going to make the test, a first year student, Vicente, arrived, wanting to develop an E-6 film in positive, just like he saw me doing it, so I gave him the warm liquids and gave him instructions about the process. Developing time 7 mn 30 sec, but insufficient fogging in the Jobo spiral, it's black plastic and he didn't want to try the tedious task of putting the wet film back on the spiral). The scans he made with an Epson 850 where very bad so he went the Fuji GFX 100 way.

His film is a brand new Ektachrome 100 E, shot with a Rolleiflex walking around Paris.

first, the colour edited images, and then the Fuji unedited raw that show a very strong bordeaux stain (he didn't developed it in wine) on all the dark areas of the film. Weird thing : you don't see that stain when looking at the slides on the light table, they look a little more like the edited version, the stain looks like a dichroïc filter...















I still have the other picture of every film holder of that batch undeveloped, waiting in the tank, it's going to wait a few more weeks...

Rudeofus said:

From looking at my experiments with different E-6 FD formulas, I would dare call Thiocyanate some kind of minus bromide compound. While bromide or other restrainers restrict fog and to some extent contrast, strong solvents seem to do the exact opposite, i.e. they simply make the developer more active.

Thiourea is yet another animal, it is both a solvent and at alkaline pH a powerful fogging agent.

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Can I ask a question here? when you refer to weak bromide compounds, is it about fogging, or does it also include color cast? I read that iodides can act as restrainers for surface development, causing slides to appear yellow-reddish, while silversolvents can remove surface halides, making slides appear cyan-bluish. As your E6-FD experience, do you have any suggestions in color cast adjustment?

Yezishu said:

Can I ask a question here? when you refer to weak bromide compounds, is it about fogging, or does it also include color cast? I read that iodides can act as restrainers for surface development, causing slides to appear yellow-reddish, while silversolvents can remove surface halides, making slides appear cyan-bluish. As your E6-FD experience, do you have any suggestions in color cast adjustment?

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I have heard of this theory from credible sources, that strong restrainers affect the top most layers most. This applies specifically to iodide, but to some extent also to bromide. As far as I have understood this, the bromide is more the "affect all layers" restrainer, while iodide is mainly the "affect the top most layers" restrainer. Taken together these can change the color of your slides. Depending on strength and concentration, and to some extent diffusion speed, a solvent can then also change resulting slide color.

Please also remember, that bromide and iodide in both E-6 developers was not just there to adjust colors. As film gets developed, a certain amount of these ions also gets released from the film itself, and the main aim was to preserve the ratio of these two over the course of several dev runs in a replenished system. Therefore the ratio between these two was meant to remain constant over time, and it was the film's job to create correct color with the such formulated E-6 developers. If you have to adjust your developers a lot for whatever reason, be prepared to forfeit some degree of reusability of these expensive liquids.

However, this is all theory, I have never really played with bromide/iodide in E-6. If my slides had off colors (and they had a lot, mostly reddish shades), adjusting temperature was the most effective way to get things back in check. I would strictly advise against adjusting properly mixed E-6 soups unless you have near perfect repeatability of process.

Rudeofus said:

I have heard of this theory from credible sources, that strong restrainers affect the top most layers most. This applies specifically to iodide, but to some extent also to bromide. As far as I have understood this, the bromide is more the "affect all layers" restrainer, while iodide is mainly the "affect the top most layers" restrainer. Taken together these can change the color of your slides. Depending on strength and concentration, and to some extent diffusion speed, a solvent can then also change resulting slide color.

Please also remember, that bromide and iodide in both E-6 developers was not just there to adjust colors. As film gets developed, a certain amount of these ions also gets released from the film itself, and the main aim was to preserve the ratio of these two over the course of several dev runs in a replenished system. Therefore the ratio between these two was meant to remain constant over time, and it was the film's job to create correct color with the such formulated E-6 developers. If you have to adjust your developers a lot for whatever reason, be prepared to forfeit some degree of reusability of these expensive liquids.

However, this is all theory, I have never really played with bromide/iodide in E-6. If my slides had off colors (and they had a lot, mostly reddish shades), adjusting temperature was the most effective way to get things back in check. I would strictly advise against adjusting properly mixed E-6 soups unless you have near perfect repeatability of process.

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Thank you for your patient and detailed suggestions! Regarding the temperature, my thought is that higher FD temperatures might increase the penetration of the developer, accelerating the development of the bottom layers and causing the sample to have a reddish tint, while lower temperatures might result in a cyan tint. Is there a significant issue with this line of thinking? I do have some samples with a reddish tint that need adjustment.

Yezishu said:

Thank you for your patient and detailed suggestions! Regarding the temperature, my thought is that higher FD temperatures might increase the penetration of the developer, accelerating the development of the bottom layers and causing the sample to have a reddish tint, while lower temperatures might result in a cyan tint. Is there a significant issue with this line of thinking? I do have some samples with a reddish tint that need adjustment.

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At least it matches my experience 100%. For a while I thought "give it 2°C more, it'll cool down inside the tank anyway, and what could get wrong?", only to end up with reddish shades and nowhere near a decent Dmax. Once I had the temperature figured out, color always came out decent looking.

Rudeofus said:

At least it matches my experience 100%. For a while I thought "give it 2°C more, it'll cool down inside the tank anyway, and what could get wrong?", only to end up with reddish shades and nowhere near a decent Dmax. Once I had the temperature figured out, color always came out decent looking.

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Thanks! I'll try the lower temperature first.