Wanting to try reversal processing but also not die

[Eldorado Quibbo]

That's interesting - where was this video posted? I've found some videos of the machine on DR5's Facebook, but it'd be useful to get a handle on what he's doing. Running a couple of rounds of intensification would not surprise me given that it could use dichromate like the bleach bath and reduce the need for having Agfa etc's level of knowledge in the dynamics and behaviour of the first developer. It is striking that the Copex films he claims won't run in his system will run just fine in the official Scala process. Almost as if Agfa knew what they were doing and invented a process that worked with different grain structure approaches...

Sorry I really don't remember where I found the video.
I clearly remember the display. There were two bleach baths, two reversal baths and some round of intensification at the end, which presumely being selenium or gold, or both.
Dr5 states is not able to run also all regular Fomas films. That's not the case because in the Foma kit Fomapan 100 (not the R version) reverses just well.

 

[Raghu Kuvempunagar]

Back around 1973 I went to a lecture by a Research student at Birmingham School of Photography, he was Reversal processing Ilford films mostly FP4 and Pan F and then making Reversal prints on Ilfobrom, the image quality was superb.

Is anything known about his process including the first developer by any chance? It's a pity if it's all lost for good.

 

[Ian Grant]

Is anything known about his process including the first developer by any chance? It's a pity if it's all lost for good.

I did make notes at the time but they are probably long gone, I don't think it was anything particularly special. Sometimes I see his ex- tutor who's French born mother was a member of the Lumiere family so photography in the blood, but there's no chance at the moment.

My main memory was the longer tonal range you could achieve by reversal processing B&W film and this was mirrored in his prints which were of exceptional quality. He did say that exposure control was very critical and it needed a lot of skill and experience. He was using Ilfobrom a graded fibre based paper and commented that reversal processing was slow because of the wash stages, RC papers hadn't been release back in 1973 and they would speed up the process very significantly.

Ian

 

[138S]

If I remember correctly in Grant & Haist excellent books, on the reversal section, there's written that the human eye cannot discern densities above 2.2 or 2.4.

But eye moves rapidly to acquire a target (saccades), it re-adjusts its exposure by adjusting "exposure" allowing by a much more wide dynamic range in practice, ultimately (after adaptation) 46 stops.

In fact Velvia slides reach near 4.0D, these are nice slides, depicting well real scenes. Often 2.2DMax slides are boring.

Sure outdoors you feel the difference between a cloudy day and an sunny day. At 2.2DMax you may show a cloudy day in the projection, at 4.0DMax an slide steals the show. No hype: a powerful show.

 

[138S]

But eye moves rapidly to acquire a target (saccades), it re-adjusts its exposure by adjusting "exposure" allowing by a much more wide dynamic range in practice, ultimately (after adaptation) 46 stops.

In fact Velvia slides reach near 4.0D, these are nice slides, depicting well real scenes. Often 2.2DMax slides are boring.

Sure outdoors you feel the difference between a cloudy day and an sunny day. At 2.2DMax you may show a cloudy day in the projection, at 4.0DMax an slide steals the show. No hype: a powerful show.

It says though color reversal films can have a maximum density of 3.0-3.5 (dynamic range >1000).

Just review what a Velvoa slide is !!!!

Here you see density of the different color channels separated, add all abd you habe 4.0DMax.

The screen flare is YMMV, it depends on room vs screen size and wall color

+

in practice the available dynamic range is reduced to 300:1 due to screen flare, ambient light and other factors.

Beyond visors and light table... just enjoy this. You nearly need sunglasses to view the slides. With that you enjoy all the DR a velvia has, or what a well processed BW slide delivers.

 

[138S]

by varying the time or intensity of the re-exposure you can fine tune the final results. alternately the timing of the 2nd developer could be varied so development wasn't to completion. I should add these were techniques used for machine processing of B&W cine reversal films.

Ian, let me to bring attention again to this graph:

What we do with unused silver ? Eliminating it with silver solvent ? Building fog if we do not eliminate it ?

Let me tell you my view on how we can use that unused silver to increase DMax without generating fog (without damaging DMin).

That unsued silver has very, very low ISO, but we fog it if we use a fogging developer or if our re-exposure is total... if our reexposure is total then that silver has to be eliminated by a solvent at some point to clear highlights...

But see next strategy:

> We don't develop or disolve the unused silver, but with a very energic first development we (infectiously) develop that unused silver in the highlights, and we clear it in those highlights with the bleaching.

> We make a controlled re-exposure that is not enough to expose the "unused silver": mostly it wont develop, it won't generate fog, we will remove it in a final fixing.

> If we use a very energing second development that "unused silver" will infectiously develop in the shadows, increasing DMax.


In that way we use the "unused silver" to get an extended DMax with no fog, so a boosted Dynamic range.


David Wood further adds a toning, wich is a kind or proportional stain that increases both contrast, and dynamic range.


Well, Fuji makes Velvia 50 with 4.0DMax power. It shines in the projection. In my experience those BW slides sporting a high dynamic range are quite powerful when projected !!

 

[Eldorado Quibbo]

But eye moves rapidly to acquire a target (saccades), it re-adjusts its exposure by adjusting "exposure" allowing by a much more wide dynamic range in practice, ultimately (after adaptation) 46 stops.

In fact Velvia slides reach near 4.0D, these are nice slides, depicting well real scenes. Often 2.2DMax slides are boring.

Sure outdoors you feel the difference between a cloudy day and an sunny day. At 2.2DMax you may show a cloudy day in the projection, at 4.0DMax an slide steals the show. No hype: a powerful show.

I dunno.
What I know is that, with my limited experience, Foma reversal kit is fabulous. It reverses excellently Fomapan 100R, Fomapan 100, Adox Scala 160 and Adox Silvermax.
Of course I dunno what Foma put in their first deleoper...

 

[Lachlan Young]

Sorry I really don't remember where I found the video.
I clearly remember the display. There were two bleach baths, two reversal baths and some round of intensification at the end, which presumely being selenium or gold, or both.
Dr5 states is not able to run also all regular Fomas films. That's not the case because in the Foma kit Fomapan 100 (not the R version) reverses just well.

Found it on the DR5 Instagram page - my transcription of the thing is: Developer/ Wash 1/ Wash 1/ Bleach 1/ Bleach 2/ Wash 2/ Clearing Bath/ Wash 3/ Reversal Neutral/ Reversal Sepia/ Stop/ Fix/ Wash 4/ 'FT'/ Wash 5/ PF [Photoflo?]/ DR [Drier?]/ Drying stage. Several things I note: the two bleaches may be to maximise bleach lifespan; the Sepia reversal bath is running at about 60oC as opposed to the neutral reversal at 27oC - makes me wonder if it's using Hypo Alum, which could have useful properties because of its bleaching effect; and the mystery 'FT' bath - could it be 'Fixer Thiocyanate' or 'Ferricyanide Thiosulfate', or one of many other options relating to clearing highlights? Or it might be something with Formaldehyde to harden the emulsion after processing.

 

[Eldorado Quibbo]

Found it on the DR5 Instagram page - my transcription of the thing is: Developer/ Wash 1/ Wash 1/ Bleach 1/ Bleach 2/ Wash 2/ Clearing Bath/ Wash 3/ Reversal Neutral/ Reversal Sepia/ Stop/ Fix/ Wash 4/ 'FT'/ Wash 5/ PF [Photoflo?]/ DR [Drier?]/ Drying stage. Several things I note: the two bleaches may be to maximise bleach lifespan; the Sepia reversal bath is running at about 60oC as opposed to the neutral reversal at 27oC - makes me wonder if it's using Hypo Alum, which could have useful properties because of its bleaching effect; and the mystery 'FT' bath - could it be 'Fixer Thiocyanate' or 'Ferricyanide Thiosulfate', or one of many other options relating to clearing highlights?

Yes, that's the video.
FT could stand for F(something like first) T= toner ? Not much likely.
I think David Wood goes the other way round. It seems he uses very powerful fogging baths that build density quickly. How to get rid of exceeding density? Using a proportional reducer...
However that Tecnolab is a beast!!
Made in Spello (Pg) Italy.

 

[Lachlan Young]

Yes, that's the video.
FT could stand for F(something like first) T= toner ?

'Flemish Toner' would be the obvious one - which is Selenium Sulfide I think

 

[Eldorado Quibbo]

'Flemish Toner' would be the obvious one - which is Selenium Sulfide I think

I tried to substitute light re-exposure using a borane redeveloper or a thiocarbamide one in the Foma kit. Both chemical redevelopers yielded very dense slides that needed farmer's reducer.
However I don't get the use of a stop bath after the chemical redevelopment: there's no need of it.
If my memory still serves me well, Kodak uses a double permanganate bleach.
Agfa suggests using of 20g/liter of sodium hexametaphosphate to lenghten the permanganate bleach useful lifespan.

 

[Donald Qualls]

Stop bath after the silver dev and sepia may be present only to limit carryover and improve fixer life, as was its primary function in amateur darkrooms for as long as most of us used acid fixer.

 

[Eldorado Quibbo]

Are redevelopers basic?
I'm assuming the sepia redeveloper to be thiocarbamide based and the neutral redeveloper to be a borane dimethylamine complex...
Anyone can chime in?

 

[Lachlan Young]

Are redevelopers basic?
I'm assuming the sepia redeveloper to be thiocarbamide based and the neutral redeveloper to be a borane dimethylamine complex...
Anyone can chime in?

The Scala process redeveloper (it's disclosed in a patent I linked to upthread) has a pH of 11.0 & is used after a light re-exposure. The first developer has a pH of 10.2

I tried to substitute light re-exposure using a borane redeveloper or a thiocarbamide one in the Foma kit. Both chemical redevelopers yielded very dense slides that needed farmer's reducer.
However I don't get the use of a stop bath after the chemical redevelopment: there's no need of it.
If my memory still serves me well, Kodak uses a double permanganate bleach.
Agfa suggests using of 20g/liter of sodium hexametaphosphate to lenghten the permanganate bleach useful lifespan.

I've linked to the patent for the Agfa bleach modification alongside the patent that appears to disclose the Scala process.

Interesting that you got dense transparencies - Foma disclose a reversal bath using SnCl2 and p-Aminophenol HCL - to be followed by a wash & then redevelopment as normal...

 

[Eldorado Quibbo]

The Scala process redeveloper (it's disclosed in a patent I linked to upthread) has a pH of 11.0 & is used after a light re-exposure. The first developer has a pH of 10.2



I've linked to the patent for the Agfa bleach modification alongside the patent that appears to disclose the Scala process.

Interesting that you got dense transparencies - Foma disclose a reversal bath using SnCl2 and p-Aminophenol HCL - to be followed by a wash & then redevelopment as normal...

I've used a Bellini prototype redeveloper based on dimethylamine borane complex.
And I've used the B part of the Foma sepia toner kit, basically a thiocarbamide solution.
In both instances I've got *very* dense slides that I've got to "lighten" with a ferricyanide reducer.
With redeveloper I mean a solution that bypass the light re-exposure, not the second developer.
That is thiourea, sulfides, dimethylamine borane, and other quite more toxic and dangerous compounds like idrazine and so on...

 

[cullah]

I've been messing around reversal development off and on for awhile now. I'm still experimenting, but I think this is my target:

Rodinal 1:10 with 2g Sodium Thiocyanate per liter for 15 minutes @ 20C with rotary agitation

I tried 1:10 at 20 minutes, and 1:5 at 15 minutes. Both were overkill, and they ended up looking faded where the blacks weren't as dark. They looked the same except the highlights were more blown out at 1:5.

I gave up on the light exposure part and went with a fogging developer since I think it was causing inconsistent results. I had to expose it to light underwater or else I would get water drops imprinted on the film.

 

[Lachlan Young]

What we do with unused silver ? Eliminating it with silver solvent ? Building fog if we do not eliminate it ?

Let me tell you my view on how we can use that unused silver to increase DMax without generating fog (without damaging DMin).

That unsued silver has very, very low ISO, but we fog it if we use a fogging developer or if our re-exposure is total... if our reexposure is total then that silver has to be eliminated by a solvent at some point to clear highlights...

But see next strategy:

> We don't develop or disolve the unused silver, but with a very energic first development we (infectiously) develop that unused silver in the highlights, and we clear it in those highlights with the bleaching.

> We make a controlled re-exposure that is not enough to expose the "unused silver": mostly it wont develop, it won't generate fog, we will remove it in a final fixing.

> If we use a very energing second development that "unused silver" will infectiously develop in the shadows, increasing DMax.


In that way we use the "unused silver" to get an extended DMax with no fog, so a boosted Dynamic range.


David Wood further adds a toning, wich is a kind or proportional stain that increases both contrast, and dynamic range.


Well, Fuji makes Velvia 50 with 4.0DMax power. It shines in the projection. In my experience those BW slides sporting a high dynamic range are quite powerful when projected !!

The films Ian was talking about these controls being used on were pre-WWII technology - heavily polydisperse, active gelatins, curve shapes not ideal, a lot of unsensitised silver. What you might have been able to get away with in the 1930's is probably going to not work terribly well with modern grain structures, additives & highly controlled growth and sensitising measures. Note too that many of the films recommended for DR5 often seem to have EI's suggested that amount to a fair bit of overexposure & that getting to box speed requires 'pushing'. That suggests that the process has issues chemically accessing the silver in an optimal way to maximise speed for many emulsions.

 

[Lachlan Young]

I've used a Bellini prototype redeveloper based on dimethylamine borane complex.
And I've used the B part of the Foma sepia toner kit, basically a thiocarbamide solution.
In both instances I've got *very* dense slides that I've got to "lighten" with a ferricyanide reducer.
With redeveloper I mean a solution that bypass the light re-exposure, not the second developer.
That is thiourea, sulfides, dimethylamine borane, and other quite more toxic and dangerous compounds like idrazine and so on...

One method I'm thinking about trying is using something like Moersch's Carbon or Siena toners to both fog & redevelop - as they're selenium sulfide or selenium polysulfide, I think the results could be interesting (I'm not particularly interested in neutral tone positives).

 

[Raghu Kuvempunagar]

my transcription of the thing is: Developer/ Wash 1/ Wash 1/ Bleach 1/ Bleach 2/ Wash 2/ Clearing Bath/ Wash 3/ Reversal Neutral/ Reversal Sepia/ Stop/ Fix/ Wash 4/ 'FT'/ Wash 5/ PF [Photoflo?]/ DR [Drier?]/ Drying stage.

This is very interesting! TFS. FT could mean Fine Tuning which might be different for different films.

I hope @dr5chrome or @Dr5 is reading this discussion of his workflow and will chip in.

 

[Raghu Kuvempunagar]

In fact Velvia slides reach near 4.0D, these are nice slides, depicting well real scenes. Often 2.2DMax slides are boring.

Quoting PE from Post #25 https://www.photrio.com/forum/threads/latitude-of-colour-negative-film.55294/

In film, due to technical reasons, reversal films are rather much limited to a dmax of 3.0 or thereabouts,
...
In any event, all of the above is true for color and B&W films.

PE

 

[138S]

Quoting PE from Post #25 https://www.photrio.com/forum/threads/latitude-of-colour-negative-film.55294/

Perhaps that was about kodak films, for sure Velvia reaches 4.0D, delivering impressive projections.

 

[138S]

The films Ian was talking about these controls being used on were pre-WWII technology - heavily polydisperse, active gelatins, curve shapes not ideal, a lot of unsensitised silver. What you might have been able to get away with in the 1930's is probably going to not work terribly well with modern grain structures, additives & highly controlled growth and sensitising measures.

Modern films also have lots of "unused silver". If you home develop BW slides you will that your slides fail to reach film DMax by a great extent.

Note too that many of the films recommended for DR5 often seem to have EI's suggested that amount to a fair bit of overexposure & that getting to box speed requires 'pushing'. That suggests that the process has issues chemically accessing the silver in an optimal way to maximise speed for many emulsions.

I see this related to clearing highlights without silver solvent, which would damage DMax.

 

[Eldorado Quibbo]

Modern films also have lots of "unused silver". If you home develop BW slides you will that your slides fail to reach film DMax by a great extent.

That has nothing to do with "unused silver" (whatever that means).
With a properly calibrated system a true DMax is achievable even at home.
Foma kit is able to deliver impressive results out of Fomapan 100R.

 

[138S]

That has nothing to do with "unused silver" (whatever that means).
With a properly calibrated system a true DMax is achiveable even at home.

My view is that is has to do with it. Unsued silver halide is the one not developed by 1st developer and that is to generate fog in the second developer if it is not removed by silver solvent in first and/or 2nd development, or by other means like a density reducer.

At home, when you use a silver solvent to clear highlights (and obtain a good DMin) you also decrease your DMax potential, as the silver you disolve won't generate density.

With a wise processing you may infectiously develop that silver to add density in the shadows and not in the highlights. Some low Dyn Range scenes won't require a high DR in the slide ...but some scenes are to benefit from an extended DR in the slide, showing bright hightlights and fully detailed deep shadows at the same time. One thing is a 2.3D Dynamic Range slide, and thing is one sporting 4.0D.

 

[Eldorado Quibbo]

My view is that is has to do with it. Unsued silver halide is the one not developed by 1st developer and that is to generate fog in the second developer if it is not removed by silver solvent in first and/or 2nd development, or by other means like a density reducer.

At home, when you use a silver solvent to clear highlights (and obtain a good DMin) you also decrease your DMax potential, as the silver you disolve won't generate density.

With a wise processing you may infectiously develop that silver to add density in the shadows and not in the highlights. Some low Dyn Range scenes won't require a high DR in the slide ...but some scenes are to benefit from an extended DR in the slide, showing bright hightlights and fully detailed deep shadows at the same time. One thing is a 2.3D Dynamic Range slide, and thing is one sporting 4.0D.

I don't really know what Foma put in their first (=second) developer in the kit but the results are stunning. A truly calibrated system with a fantastic emulsion. This is my piece of advice to the original poster: get the Foma reversal kit and the Fomapan 100R. You'll save yourself tons of money of burned films and spare time.
Grant & Haist states that the silver halide solvent has also the function of physically develop the Ag specks so to redeposit some Ag in the growing area. This allow a greater DMax achievable.