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

billy howards · Sep 20, 2020

hello everyone...

so after a bunch of trials using b&w developer as my E-6 FD (HC-110 at various strengths & development times, HC-110 with TSP added to raise the pH, dektol at various strengths & development times), but still getting rather dark images with no highlights, i decided to try a dedicated E-6 FD...

https://cinestillfilm.com/products/...r-high-dynamic-range-slides-powder-8-16-rolls

so, i used that (1:2 ratio at 104 degrees for 10:30)...then fogged the film by exposing to light...and then used the kodak c-41 flexicolor chemistry to do the rest...c-41 dev, bleach, fix, rinse...

and, to my surprise, i still ended up with really dark images...no better than by using the b&w chemistry.

i did noticed however, that when i took the film out after the FD, it looked more like a b& w negative than i've ever seen...it had darks & lights & was almost transparent in places.

from everything i've read, dark E-6 film is always associated with the FD. is this true? could my use of C-41 chemistry be the culprit? does anyone know this...when using C-41 chemistry with C-41 film, developing for longer yields lighter, almost overexposed negatives. if you're using C-41 dev as an E-6 second developer, would leaving it in the tank for too long yield the opposite...ie: dark images, as you end up with a positive?

thanks everyone!

Donald Qualls · Sep 20, 2020

I'd expect overall dark E-6, if using in-date film and exposing at box speed, to result mainly from excess undeveloped halide after the FD -- but yes, overdeveloping the color dev in E-6 will also darken the slides (while increasing color saturation and contrast), if there's enough halide left to expose/develop to that density.

One way to lighten the slides (I've done this with B&W reversal, haven't done E-6 yet) is to add a small amount of thiosulfate or thiocyanate to the first developer. This will dissolve some of the undeveloped halide, leaving less for the reversal to expose and the color developer to develop. With Tri-X, using a pretty standard reversal process, I picked up about 2/3 stop, getting good looking slides at EI 640 -- that would have been 2/3 to 1 stop underexposed with plain Dektol as first dev. The final first dev I used (this is for Tri-X, remember, but ought to be close) I used the Dektol at 2 parts stock to one part water, added 8 g/L sodium thiosulfate and 4 g/L potassium bromide, and developed for 12 minutes. My second developer was very normal for the film used (HC-110 B for 7 minutes, comparable to 3:15 at 100F for C-41).

grainyvision · Sep 20, 2020

billy howards said:
hello everyone...

so after a bunch of trials using b&w developer as my E-6 FD (HC-110 at various strengths & development times, HC-110 with TSP added to raise the pH, dektol at various strengths & development times), but still getting rather dark images with no highlights, i decided to try a dedicated E-6 FD...

https://cinestillfilm.com/products/...r-high-dynamic-range-slides-powder-8-16-rolls

so, i used that (1:2 ratio at 104 degrees for 10:30)...then fogged the film by exposing to light...and then used the kodak c-41 flexicolor chemistry to do the rest...c-41 dev, bleach, fix, rinse...

and, to my surprise, i still ended up with really dark images...no better than by using the b&w chemistry.

i did noticed however, that when i took the film out after the FD, it looked more like a b& w negative than i've ever seen...it had darks & lights & was almost transparent in places.

from everything i've read, dark E-6 film is always associated with the FD. is this true? could my use of C-41 chemistry be the culprit? does anyone know this...when using C-41 chemistry with C-41 film, developing for longer yields lighter, almost overexposed negatives. if you're using C-41 dev as an E-6 second developer, would leaving it in the tank for too long yield the opposite...ie: dark images, as you end up with a positive?

thanks everyone!

So this might be crazy, but are you using proper C-41 developer? Have you tried this on normal C-41 film and got normal density? The only way you can get dark slides like this without any fault of the FD is either under exposure or an extremely overactive color developer that effectively "fogs" the film. This could be the case for instance if you're using replenisher without starter

otherwise, I'd say you need to check that your camera is exporting properly

billy howards · Sep 20, 2020

earlz said:
So this might be crazy, but are you using proper C-41 developer? Have you tried this on normal C-41 film and got normal density? The only way you can get dark slides like this without any fault of the FD is either under exposure or an extremely overactive color developer that effectively "fogs" the film. This could be the case for instance if you're using replenisher without starter

otherwise, I'd say you need to check that your camera is exporting properly

i'm using c-41 flexicolor starter & replenisher for my c-41 negatives, and they are all coming out perfectly. in the instance of doing c-41, the developer is in the tank for 3:15. when used as the second developer for E-6, it's in the tank for 4:30 (a time i believe i picked up somewhere in this thread). i'm curious if this extra 1:15 might be the problem though. the c-41 developer is 1-shot, so always fresh & full strength.

halfaman · Sep 20, 2020

Ok, here is my "theory"...

In a negative film the dye formation during C-41 CD produces a restrainer that stops the silver development, so it is never complete and gives the extreme highlights latitude we are used to in color negatives (very controlled density of highlights). In E-6 the color development is done up to completion, so when C-41 CD is used in a reversal process it will develop all silver halide available and form as much dyes as possible from it.

So the problem is that your FD leaves too much silver halides undevelop for C-41 CD.

I can think in several things to do: Add a restrainer to C-41 CD (like sodium sulfite that inhibit the dye formation), increase FD development time (more silver created and less halides available for CD), add a silver halide solvent to FD (a little quantity of a fixer compound to disolve some silver halides, so less for CD). How much? No idea

I see you are using a tweaked FD for "extended highlights", that could be also a problem for you. To extend the highlights you need to develop them less during FD so there is some more halides for the CD.

billy howards · Sep 20, 2020

thanks everyone for your replies/theories/advice.

the first time i tried this b&w & c-41 for E-6 process was with the old HC-110 syrup, and it was the most successful (see several posts ago). i felt like a photo god when i saw the film come out of the tank...but then the second attempt with the new HC-110 was the beginning of several less than successful tries. having said that, even with the original HC-110 i didn't have many highlights...like, if you divided a histogram in half vertically, there was no information to the right of the dividing line. lately, the histogram seems to only have info at the bottom 1/3rd.

question...what is the film supposed to look like right after the FD & before the fogging? i've had everything from virtually black to something resembling a b&w negative. in addition, could my fogging process be having an effect on my highlights?

donald qualls & halfaman, i'll do some experiments with your various suggestions.

thanks so much, i really appreciate this forum!

and big thanks to earlz for starting this thread!

billy howards · Sep 30, 2020

well, a few experiments later and i had a breakthrough.

but first, some more failures.

donald qualls...i tried your advice and added 8 g/L sodium thiosulfate and 4 g/L potassium bromide to a 2:1 dektol mixture for the FD. (it was 35mm, so 2.4 g/300ml & 1.2 g/300ml respectively).

when i took the film out for fogging, it looked promising...i could see images clearly...but then after the c-41 process i ended up with extremely pale, B&W, solarized looking negs. (having said that, one of the pictures was my favourite in months...it looked like it was beamed in from 1880, so it wasn't a total wash).

then i tried leaving it in the CD for shorter...3:30...but i still got dark images.

halfaman, your suggestion was up next, so i ordered some sodium sulphite to add to the CD, but my supplier was on backorder.

after all that, i just decided to go back to earlz original suggestion of HC-110 as the FD, despite only having the new formulation...but i'd pay very specific attention to my measurements & temperatures & timing. i also added a pre-soak in water at 104F for a minute, and used a stop after the FD...both of which were ideas i'd found here & there.

so...

the process:

-pre-soak film 1 min in water at 104F
-HC-110 at 104F for 7 mins
-rinse with water
-stop bath for 30 secs
-rinse again with water

-fog both sides of the film for 90-120 seconds at 6" from a full spectrum light

-C-41 dev at 100F for 4:30 mins
-C-41 bleach for 10 mins
-rinse with water
-C-41 fixer for 10 mins
-rinse with water
-soak in final rinse

and the images came out incredibly!

and now the punchline...

when i went to write this all down, i realized that in my attempts to make HC-110 dilution A, i accidentally doubled the amount of syrup used...so instead of 1:15, it was 1:7.5.

now that i'm in the ballpark, i'm going to play around a little bit...maybe shorten the FD time, or reduce the syrup to water ratio down to 1:10.

thanks again to everyone who helped out!

Donald Qualls · Oct 1, 2020

billy howards said:
donald qualls...i tried your advice and added 8 g/L sodium thiosulfate and 4 g/L potassium bromide to a 2:1 dektol mixture for the FD. (it was 35mm, so 2.4 g/300ml & 1.2 g/300ml respectively).

when i took the film out for fogging, it looked promising...i could see images clearly...but then after the c-41 process i ended up with extremely pale, B&W, solarized looking negs. (having said that, one of the pictures was my favourite in months...it looked like it was beamed in from 1880, so it wasn't a total wash).

Thiosulfate in the first developer lightens the image, so this suggests you have too much -- I'd try cutting it by half (and the bromide as well). C-41 halide appears to be tabular in nature (based on fixing times for XP-2 in B&W chemistry), and there's less silver (even in three or four layers) than there would be in a B&W film the same speed, even tabular grain (because the dye cloud image amplifies the density). Even with slower fixing due to tabular halide, the lower total silver content may make my figure (which was tested on Tri-X) too high.

OTOH, if your'e getting good images with HC-110 at roughly Dilution A, you could just carry on what you're doing. Your process will cost a little more, but still likely less than a genuine E-6.

Hunter_Compton · Dec 3, 2020

Since reading about this process a few months ago, I wanted to try it myself. I am happy to say that I found the OP's method quite exemplary when applied within optimized parameters.

I cannot attest to the viability when utilizing the new HC-110 formulation, as I am still working through a liter of syrup I bought a couple of years ago.

Seeing as Provia 100F seems to be the best film stock used with this method, I tested it using a roll of Provia I had that was about two years out of date. I shot at box speed and developed using the method first described by the OP with the addition of an acetic acid stop bath after the first developer to prevent solarization during re-exposure.

Re-exposure was accomplished by removing the film from the reel and exposing each side for 60 seconds using a 500 lumen LED flashlight. I use a Paterson tank, and did find some difficulty in replacing the film on the reel, but was able to do it by submerging the reel and film in a bucket of water. In the future I will attempt re-exposure on the reel.

My C-41 chemicals were a Cinestill CS-41 powder kit that I mixed about two months ago, and have developed 5 previous rolls in. Color developer time was 4:15 and Blix was twice the kit time of 8:00 at 16:00.

I found the results to be quite good in terms of color reproduction. Please excuse the poor cell phone photo, but the scans were adjusted for levels only, with no color correction. Concerns were expressed earlier in this thread about the suitability of this process for projection. I mounted a few of these slides and ran them through a Kodak carousel projector, I believe the maximum density to be sufficient for this use. Since the color developing agent is different, and I understand that E-6 processing uses formalin where C-41 does not, I do not believe that the color dyes will be as lasting when used for projection, although I have not yet tested this sufficiently to draw a definitive conclusion.

Bisco · Apr 7, 2021

I followed the advice from billy howard using the 1:10 dilution with provia and all else being the same I got quite good results. To the eye the slides look similar to the roll of provia I developed from the same day in proper e6 chemistry (from cinestill atleast). This technique is absolutely viable!!

YoIaMoNwater · Apr 7, 2021

@earlz Have you tried this with expired slides at lower temperature? I got couple rolls of Agfachrome (expired in the 80s) that I'm thinking of trying with Rodinal. I'm just curious on whether a lower develop temperature could help in reducing overall fog.

grainyvision · Apr 8, 2021

YoIaMoNwater said:
@earlz Have you tried this with expired slides at lower temperature? I got couple rolls of Agfachrome (expired in the 80s) that I'm thinking of trying with Rodinal. I'm just curious on whether a lower develop temperature could help in reducing overall fog.

I have tried this with expired film. Mine was from the 90s and poorly stored (some Fuji brand stuff). I didn't use a lower temp though and instead used HC-110 dilution B instead of A and I think 5m development time. Lowering temperature will likely lead to color casts since temperature dictates how the developer penetrates the emulsion. I only shot a set of brackets to see how it'd turn out and they were far from ideal, but much better than processed normally. Processed normally the film was almost completely clear due to so much age fog, and in this method there was about a middle grey black density with green cast. I believe the film speed was naturally 100 and according to the brackets the best results were shot at about ISO 12, so its a definite big speed decrease by doing this. Saturation and contrast were also on the lower side. Personally I'd recommend cross processing as C-41 negative instead though since negative processing is much easier to compensate for age fog.

Also I can't remember the exact timeline for Agfachrome, but there is some older version (maybe 60s or 70s) which used a process incompatible with all modern color processes. I believe the process was similar to Kodachrome. Either way, worth checking if the film isn't clearly labeled as being E-6 process. I have a roll of this film and color developer does absolutely nothing to it other than develop some silver which clears with bleach. I keep it on display rather than trying to do anything with it

YoIaMoNwater · Apr 9, 2021

earlz said:
I have tried this with expired film. Mine was from the 90s and poorly stored (some Fuji brand stuff). I didn't use a lower temp though and instead used HC-110 dilution B instead of A and I think 5m development time. Lowering temperature will likely lead to color casts since temperature dictates how the developer penetrates the emulsion. I only shot a set of brackets to see how it'd turn out and they were far from ideal, but much better than processed normally. Processed normally the film was almost completely clear due to so much age fog, and in this method there was about a middle grey black density with green cast. I believe the film speed was naturally 100 and according to the brackets the best results were shot at about ISO 12, so its a definite big speed decrease by doing this. Saturation and contrast were also on the lower side. Personally I'd recommend cross processing as C-41 negative instead though since negative processing is much easier to compensate for age fog.

Also I can't remember the exact timeline for Agfachrome, but there is some older version (maybe 60s or 70s) which used a process incompatible with all modern color processes. I believe the process was similar to Kodachrome. Either way, worth checking if the film isn't clearly labeled as being E-6 process. I have a roll of this film and color developer does absolutely nothing to it other than develop some silver which clears with bleach. I keep it on display rather than trying to do anything with it

Thanks for the info earlz. I've been experimenting with B&W reversal for a bit and your process seems almost similar with the exception of the 2nd developer being a color one. I just checked the films and they are Agfachrome 200RS and CT100, thankfully they have the E6 process shown on the box. I'm thinking of using concentrated Rodinal for the first developer at 20C then do the color development at usual at 38C. When you say lowering the temperature will lead to color casts, do you mean for the first developer or color developer? My understanding is that the first developer will need to be concentrated enough to develop almost all of the silver so then the dye layers can be further developed with the 2nd developer.

If I have time in the near future I'll try opening both rolls of 200RS and CT100 inside a changing bag then cut the film leaders and try to develop them in Rodinal to test for the conditions for minimal fog.

billy howards · Apr 9, 2021

Bisco said:
I followed the advice from billy howard using the 1:10 dilution with provia and all else being the same I got quite good results. To the eye the slides look similar to the roll of provia I developed from the same day in proper e6 chemistry (from cinestill atleast). This technique is absolutely viable!!

the measurements, temp & timing for the new HC-110 that i ended up feeling yielded the best results were:

EKTACHROME
-7.89:1 at 100F for 7 mins

PROVIA
-9:1 at 104F for 6:30 mins

mohmad khatab · Sep 17, 2021

Donald Qualls said:
I'd expect overall dark E-6, if using in-date film and exposing at box speed, to result mainly from excess undeveloped halide after the FD -- but yes, overdeveloping the color dev in E-6 will also darken the slides (while increasing color saturation and contrast), if there's enough halide left to expose/develop to that density.

One way to lighten the slides (I've done this with B&W reversal, haven't done E-6 yet) is to add a small amount of thiosulfate or thiocyanate to the first developer. This will dissolve some of the undeveloped halide, leaving less for the reversal to expose and the color developer to develop. With Tri-X, using a pretty standard reversal process, I picked up about 2/3 stop, getting good looking slides at EI 640 -- that would have been 2/3 to 1 stop underexposed with plain Dektol as first dev. The final first dev I used (this is for Tri-X, remember, but ought to be close) I used the Dektol at 2 parts stock to one part water, added 8 g/L sodium thiosulfate and 4 g/L potassium bromide, and developed for 12 minutes. My second developer was very normal for the film used (HC-110 B for 7 minutes, comparable to 3:15 at 100F for C-41).

View attachment 255370

Brother: Donald.
What was the brand of this film that you used in the production of that picture?

Donald Qualls · Sep 20, 2021

mohmad khatab said:
What was the brand of this film that you used in the production of that picture?

The B&W reversal I've done previously (about 2005-2006) was expired Tri-X, from before the upgrade to formate doped halide that made the grain finer at the same speed.

mohmad khatab · Sep 21, 2021

Donald Qualls said:
doped halide that made the grain finer at the same speed.

Hello my dear brother ,
On the whole, this movie and that process is not within the main topic of this thread
- But actually I'm interested to know from you (if you don't mind), how did you manage to make the grains more precise (ultra-fine) and at the same speed as the film?

flavio81 · Sep 21, 2021

mohmad khatab said:
Hello my dear brother ,
On the whole, this movie and that process is not within the main topic of this thread
- But actually I'm interested to know from you (if you don't mind), how did you manage to make the grains more precise (ultra-fine) and at the same speed as the film?

Hello Mohmad,

Reversal process should give visually finer grain than the same film in negative process, because the image is made of film grains that have been exposed at the same (high) density. Thus the grain is more uniform to the eye.

This is why slide films are often finer grained than their negative counterparts. However, for various reasons, negative films are sharper and give truer colors.

mohmad khatab · Sep 21, 2021

flavio81 said:
Hello Mohmad,

Reversal process should give visually finer grain than the same film in negative process, because the image is made of film grains that have been exposed at the same (high) density. Thus the grain is more uniform to the eye.

This is why slide films are often finer grained than their negative counterparts. However, for various reasons, negative films are sharper and give truer colors.

Thank you, brother Flavio.
Greetings to all the respected people of Lima.

Donald Qualls · Sep 22, 2021

@mohmad khatab As @flavio81 noted, reversal processing black and white film will generally result in finer grain structure than a negative from the same film. As I understand it, this is because the larger grains are the more sensitive, so they get exposed and develop in the first developer, then bleached away; this leaves the smaller and less sensitive grains to be exposed or chemically fogged for the second developer. In other words, your final positive image is made up of the silver that would normally have been too fine and insensitive to get exposed and developed, and hence fixed away in a negative process.

This principle has only limited application to color films, however, because the image left at the end of the process is dye clouds, rather than silver grains, and generally "grain" is less visible when the dye clouds are denser, and the pre-development halide grain size contributes little to the final result.

mohmad khatab · Sep 22, 2021

Donald Qualls said:
@mohmad khatab As @flavio81 noted, reversal processing black and white film will generally result in finer grain structure than a negative from the same film. As I understand it, this is because the larger grains are the more sensitive, so they get exposed and develop in the first developer, then bleached away; this leaves the smaller and less sensitive grains to be exposed or chemically fogged for the second developer. In other words, your final positive image is made up of the silver that would normally have been too fine and insensitive to get exposed and developed, and hence fixed away in a negative process.

This principle has only limited application to color films, however, because the image left at the end of the process is dye clouds, rather than silver grains, and generally "grain" is less visible when the dye clouds are denser, and the pre-development halide grain size contributes little to the final result.

You are a really kind hearted and respectful man, thank you.

Caleb Hauge · Apr 24, 2023

I found that straight D-76 put into my Patterson tank at roughly 110 F for 12 minutes (allowed to drift to around 104 F) gives great results with Ektachrome E100. Color dev was done with CineStill Cs41 at 102 F for 5 minutes because of my almost exhausted color developer. Blix was 16 minutes. The slides are ever so slightly cyan tinted, and reds are a tad weak, but they look very good otherwise. I've only done two rolls like this, so I'm still tweaking it. I'll try a roll at a longer dev time soon. Color dev was done with CineStill Cs41 at 102 F for 5 minutes because of my almost exhausted color developer. I re-exposed for a few seconds over each image with my iPhone SE flashlight.
My scanning setup is terrible. There isn't any chromatic aberration IRL, and the green tint outside of the center of the slides isn't there IRL. I'm just taking pictures of the slides in a cheap personal slide viewer with a Nikon Coolpix L820 (DSLR is broken at the moment).
Links to pics:

EPR box (1st attempt)
Clouds (1st attempt)
Berries (2nd attempt)
Broken Down Dam (2nd attempt)
Broken Down Dam (2nd attempt, color corrected)
Graffiti on Broken Down Dam (2nd attempt, looks similar IRL. Great example of the weak reds)

wblynch · Apr 24, 2023

Pretty cool. They have a vintage look.

Caleb Hauge · May 11, 2023

I tried it again with some expired Velvia (03/2012, unknown storage, came from Ohio) and I had the best results yet. I did 12 minutes of first dev with stock D76. It was 110 F when I poured it in, but I let it naturally cool down in my paterson tank. Afterwards I followed the normal instructions for my CineStill DynamicChrome kit. D76 seems to work much better as a first developer than the actual CineStill first developer. There were no noticeable color shifts other than a very slight green haze, which is could down to the Velvia being expired. It might even be because of the stormy weather that day. I'd suggest doing it for a little less time than I did - maybe 11 or 10.5 minutes. It ended up being a bit overdeveloped, and lighter pastel colors were almost totally white. I'll develop another roll tonight and see how it goes with 11 minutes of first dev.

Caleb Hauge · May 12, 2023

This time I did 11 minutes of stock D76 as first dev, ~110 F starting temp then drifted to ~100 F. The rest of it was done as the CineStill Cs6 DynamicChrome instructed. The slides are a little dark and maybe slightly underdeveloped, but colors are much more accurate and saturated (though nowhere near what you'd expect from Velvia 50, though it is expired). Overall, I'd call this a success.

Crappy phone pics:

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

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