B&W Reversal Processing-Fomapan R100 Reversal Bath Formula

[John Cee]

Has anyone experimented with the Fomapan R100 Reversal Bath Formula on R100 film or for reverse processing any other black and white film? The formula is given on the technical data sheet for Fomapan R100 which can be found at the link below

http://www.foma.cz/en/catalogue-fomapan-r-100-detail-273

The chemicals appear to be available from Photographers Formulary, although some are apparently known by different names here in the United States. EDTA Disodium Salt sold by PF (Photographers Formulary) appears to be the same as Chelaton III in the Fomapan process? Stannous Chloride sold by PF appears to be the same chemical as Tin Dichloride in the Fomapan process? Finally, Glacial Acetic Acid 99% sold by PF seems the same as Essigsaure 60% (except for the concentration of course).

So has anyone tried home-brewing this formula for use with R 100 or any other B&W film? I have been using re-exposure to light and have read some interesting threads about using Super Iron Out for a reversal bath. Complicated is not always better. Having said that this formula has more components than Super Iron Out and may be more adaptable to different film emulsions. Many experts opine that chemical reversal is superior in terms of consistency and quality compared with re-exposure to light. The Darkroom Cookbook avoids discussing chemical reversal baths and Photographers Formualry was no help with the question. I have not been able to spot another APUG thread that addresses this specific issue. Any shared experience or advice appreciated.

 

[John Cee]

Thanks Alessandro. I have some Super Iron Out on hand but have been reluctant to try it because I did not know the exact content. Your solution makes more sense to me. I may give that a try. Do you find using sodium dithionite superior to re-exposing to light. Also do you have a suggestion for how long in the bath and for agitation?

 

[Gerald C Koch]

Be very careful with the sodium dithionite as it is a very powerful fogging agent. Promptly and thoroughly clean up any solid and liquid spills to avoid problems later with other photographic materials. Any dust containing this chemical has the opportunity to create spots should it land on an undeveloped emulsion.

I have developed many rolls of color reversal film without any problems with re-exposure. It is easy and dependable. It is practically impossible to over-expose when using this method.

 

[John Cee]

Thanks for the advice Gerald. I have been doing E6 and C41 for years and have been experimenting with B&W reversal for several months now. What I have discovered this morning is that Sodium Dithionate (better known as Sodium Hydrosulfite here is the USA) is quite expensive to purchase and ship here in the US. A 500g quantity is $105 USD from Cole Palmer plus about $40 in shipping because of its hazmat status. So I am not sure I want to go that direction. I have been using the re-exposure to light technique and it is working ok but it is awkward especially for rolls of 135/36 and reloading wet film back on a spool is time consuming. I have had a few instances where water drops on the film while re-exposing affected the film in those areas-so now I am more careful in trying to avoid those. So I was looking for an alternative. The chemicals in the fomapan R100 process are available from Photographers Formulary, but I really don't want to make that investment blindly and so was looking for advice. I am also considering making some sort of light bar and hanging the film to make the re-exposure easier as another alternative. Thanks again for the helpful advice.

 

[destroya]

Hi John,
I've personally followed another road using Super Iron Out in it's purest form, that is only sodium dithionite.
It blackens any emulsion very fast, very consistently and much more important, to it's highest DMax.
The recipe couldn't be simpler: two heaped teaspoons of sodium dithionite in 300ml ow water and that's it!

+1. It works great

 

[John Cee]

Just following up regarding the Fomapan Reversal Bath formula-Since I was unable to find anyone who had tried replicating the formula, I decided to try a test roll using the Super Iron Out. My very preliminary results show that it is as effective and even perhaps a tad superior to re-exposure to light. It is certainly faster and more convenient. Encouraged by these results and wanting to extend the top of the curve more, I have decided to experiment with the Kodak FD-70 reversal formula. Below is one of the images from my test roll of FP4 using Super Iron Out. The DMax is not what I would like, but not sure what the potential of FP4 reverse process is. DR5 claims 3.4 with compressed contrast, so perhaps that is the best that one could hope for?



FP4 135 @ISO100
1st developer D-11(1:1) + 4g/l Sodium Thiocyanate
Dichromate bleach
Potassium Disulfite Clearing Bath
Super Iron Out @ 2 tsp per 300ml of water
D72 2nd Developer (2:1)

 

[John Cee]

Thank you Alessandro. Will give that a try while waiting for the chemicals for FD70 to arrive.

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