Help needed with bromoil

[TimberwolfII]

Having a go at this technique but struggling. Done lots of research and watched plenty of videos so I kind of know what to expect, but something isn’t right.

So, got a relatively low contrast image as recommended in some places, printed it flat. Foma 113 bo paper developed with adox neutrol. Fixed with pure hypo, washed and hypo cleared with 2% sodium sulphate solution. Bleached back with bleach tanner-
5% Sulphuric acid
60g coppersulphate
60g potassium bromide
5g potassium dichromate

Stock bleach tanner diluted 1:9 for use. Matrix then dichromate cleared with sodium metabisulphate. Matrix fixed with pure hypo. Matrix fully washed. Matrix dried. Matrix soaked for twenty mins.

Matrix placed on flat surface and excess water blotted off so matrix surface damp but no droplets.

Litho ink used on hoof shaped stipple brush.

This is where issue is, there doesn’t seem to be any distinction between light and dark areas in the gelatine. The image is fractionally there, fractionally. But when stippling it is Fiendishly hard to achieve ANY contrast. Many times impossible. Everything I have seen the ink takes to the dark areas (little gelatine) quite simply, resoaking allows contrast to be built.

I’m just not getting the image, there is no differentiation in the gelatine apparently. I also got random artefacts in the one image I have managed.



Original image

[TimberwolfII]

Bromoil image.

[koraks]

Is your clearing bath actually sodium sulfate and not sulfite? If it is, this may be your problem.

[Jim Noel]

Take a look at this informational article.
https://www.unblinkingeye.com/Articles/Brom/brom.html

[TimberwolfII]

Koracs - I’ve been following this post : https://blog.scienceandmediamuseum.o...omoil-process/

It says sodium sulphate for the clearing. Is that wrong?

[TimberwolfII]

Jim, yes the article is great. Thank you for pointing it out.

From extensive reading today, I’ve found several posts online with my exact symptom (unfortunately no unequivocal successful end points), which suggest a lack of tanning. Tanning takes longer than bleaching apparently, much longer. I’ve bleached successfully, but I’ve absolutely no differentiation in the gelatine. I’ll try a lot longer in the bleach tan, but I thought I’d done the ten minutes recommended. I’ll revisit.

[koraks]

Koracs - I’ve been following this post : https://blog.scienceandmediamuseum.o...omoil-process/

It says sodium sulphate for the clearing. Is that wrong?

Yes, that's wrong. There's an error on that website. They mention hypo clear, and then instruct to use sulphate, but hypo clear is sodium sulfite. I suspect the sulphate may harden the emulsion, which could explain your problem. Insufficient tanning could also be an issue of course, but it might be exacerbated by the sulfate/sulfite mixup. In any case, sulfate does not make sense to me in this application!

[TimberwolfII]

Ok, that’s good. I will correct that error, increase the tanning time and do a re-run. I’ll report back to. So many of the queries about this difficulty dead end and are not very useful to those looking for solutions to similar issues.

Thank you team largeformatphotography.

[Wayne]

How did you get dichromate in the UK? i thought it was banned, or is that just the mainland?

Edit: on 2nd thought, you don't need to tell me. What happens in LF stays in LF

[TimberwolfII]

It’s definitely not banned, it is restricted. It cannot be purchased by private individuals from laboratory suppliers. It can only be supplied to a registered business and delivered to a registered business address. I purchased it in that approved manner.