Filmotec/Orwo B&W Reversal processing

[Ian Grant]

First Developer ORWO 829
Solution 1:
Water (35°C) 750.0 ml
Sodium sulphite 25.0 g
Phenidone 0.2 g
Hydroquinone 10.0 g
Sodium carbonate 20.0 g
Potassium bromide 6.0 g
Potassium thiocyanate 6.0 g
Solution 2:
Water (20°C) 125.0 ml
Sodium hydroxide 5.0 g
After cooling down solution 1 pour
solution 2 into it and
Make up with water to 1 litre


Bleaching bath ORWO 833
Water 750.0 ml
Potassium dichromate 10.0 g
Sulphuric acid. conc. (caution) 15.0 ml
Water to 1 litre


Clearing bath ORWO 835
Water 750.0 ml
Sodium sulphite 90.0 g
Water to 1 litre


Second Developer ORWO 842
Solution 1:
Water (35°C) 750.0 ml
Sodium sulphite 25.0 g
Phenidone 0.2 g
Hydroquinone 10.0 g
Sodium carbonate 20.0 g
Potassium bromide 6.0 g
Solution 2
Water (20°C) 125.0 ml
Sodium hydroxide 5.0 g
After cooling down solution 1 pour
solution 2 into it and
Make up with water to 1 litre


Fixing bath ORWO 300
Water 750.0 ml
Sodium thiosulphate 5 hydrate 200.0 g
Potassium Metabisulphite 20.0 g
Water to 1.0 litre

__________________________________________________ __________________________________
Processing at 20°C:
Times Minutes:Seconds

1 First development (ORWO 829) 5:15 mins 20° ± ½°
2 Washing -running ater 2 mins
3 Bleaching (ORWO 833) 2 mins
4 Washing - running water 1 min
5 Clearing (ORWO 835) 1:30 mins
6 Washing - running water 1 min
7 Second exposure approx. 8.000 lxs
8 Second development (ORWO 842) 2:40 mins 20° ± ½°
9 Washing - running water 30 seconds
10 Fixing (ORWO 303) 1:30 mins
11 Washing - running water 3 minutes


This process is designed for the Commercial Reversal processing of Filmotec Movie film. But should work well with any modern B&W film. You will need to experiment with the first development time and EI to find the best combination for your purposes.

The First Developer & 2nd Developer are identical except for the Potassium Thiocyanate in the first.

[Ian Grant]

I've got excellent results, at least to my eyes, using Tetenal Eukobrom and Dokumol with 2,5g of thiosulphate in 250ml of working solution.

Dunno why thiocyanate will yield better results than thiosulphate.

I don't have the books with me that go into the advantages/disadvantages of Thiocyanate/Thiosulphate but Thiocyanate is more effective and so you use less. I guess it's also for the same reason that Thiocyanate was used in extra fine grain developers rather than Thiosulphate, it produces less dichroic fog during processing.

Over the years I've used both but with different developers, so that clouds my judgement, but you are right excellent quality is achievable using a print developer & Thiosulphate.

Ian

[Photo Engineer]

Thiosulfate decomposes slowly in solution and loses potency therefore making the developer more variable. Also, the risk of dichroic fog is increased. As Ian mentions, hypo is also less efficient at the same concentration as thiocyanate.

PE

[Alessandro Serrao]

Thiosulfate decomposes slowly in solution and loses potency therefore making the developer more variable. Also, the risk of dichroic fog is increased. As Ian mentions, hypo is also less efficient at the same concentration as thiocyanate.

PE

So using a fresh one-shot thiosulphate solution and maybe a pinch of potassium bromide should make it...
Hypo is also much cheaper than thiocyanate...

[Ian Grant]

Yes, and the extra Bromide is a very common part of a B&W Reversal First developer. I'm in the middle of number crunching these developers as I write. Both the formulae using Thiosulphate add it just before use.

Ian

[Mick Fagan]

Ian, with step 7 of the process, how important is the intensity of the second exposure, can you over do it without too much of a problem?

In other words, allowing for most home darkroom lighting set-ups, what do you think would be a suitable situation.

Mick.

[Ian Grant]

Mick, the secret is adequate exposure, Ilford's recommendation is "30-60 seconds at 46cm/18in from a 100-watt tungsten lamp" but go on to say 2-4 times this is safe. In the past I've also used a 275w Photoflood but the distance is increased to about 6ft (2 metres). So there's plenty of le-way.

Heavy reversal exposure particularly to sunlight can cause major problems with the image partially inverting giving a sort of solarised effect.

Ian

[Mick Fagan]

Thank you Ian, I have in the past done quite a fair bit of reversal processing of FP4 and FP4+.

I have always used a tungsten 60W bed lamp stuck on my darkroom wall for the second exposure. Generally I have taken about 15 seconds to get the film off the reel, then I expose for around 20 seconds each side, then the film is in the light as I re-wind back on the reel. The exposure was obviously all right as my films came out quite well.

I have an application in the new year for B&W trannies and I actually was looking on Apug when my search turned this thread up.

Except for two chemicals I have everything, so I'll get them and have a go next year.

Mick.

[Alessandro Serrao]

Ian: can you provide a *valid* chemical second exposure recipe?
I feel taking the film off the reel is begging for problem for me, I use a permanganate bleach.
Thanks.

[Ian Grant]

Alessandro if you use a Paterson or other translucent reel it is possible to re-expose while the film's still on the reel.

I do have manufacturers chemical reversal baths, also Fogging Developers, some of the chemicals are not that easy to get hold of. I'll have to dig them out, I've not put them in my database yet. There's Kodak FD-72 which uses sodium dithionite, but it's not very stable once mixed and only lasts a couple of hours. Stannous chloride and derivatives of hydrazine can be used and also Sodium Sulphide or alkaline Thiourea (Thiocarbamide). I'll post some ideas for you as soon as I get time to sort them out.

Ian

[Photo Engineer]

Ian;

There is the old standby, Stannous Chloride for reversal. The others you mention such as Sodium Sulfide and Thiourea are really baths that precipitate Silver Sulfide and cause a brown-black image to form. These can interfere with imaging as they can react with the Silver Sulfate formed in the bleach if washing is insufficient.

The Stannous Chloride is currently used in E6 and is not very stable. Before this, E4 used t-Butyl Amine Borane which was quite toxic.

As for overexposure with light, I have never heard of it. If the silver is properly developed in the first developer, you cannot overexpose using light. If that were possible, then the reducing reversal baths would be impossible to control and even worse for this "solarization" effect.

Kodak only warns about overheating the emulsion and causing reticulation, or splashing the bulb and shattering it. The only place I know of that you can overexpose during reversal is Kodachrome processing.

PE