First off, thanks to the great work of Denise Ross and others on these forums, I was able to succeed in making my first batch of emulsion! I used the TLF AmBr recipe but substituted 5g of KBr for the NH4Br, and aside from a few rookie mistakes, managed to follow it mostly faithfully. Success! Despite being extremely slow (as expected), the plates processed quite nicely in D-23 and TF-2, and I am now the proud owner of my first completely hand-made (if woefully translucent) glass step wedge.
But of course I couldn't leave well enough alone and decided to experiment a bit with my second batch, because SPEED. I didn't have ammonium thiocyanate on hand to make Steigmann's solution, but understood that hypo could be substituted, so attempted to do the molar math and ended up with roughly:
6 drops 2% sodium thiosulfate
6 drops 0.1% gold chloride
Per recipe of emulsion, mixed into 5ml of ethanol along with:
2 drops 10% potassium bromide
14 drops 0.5% erythrosine
The solution was then mixed into the washed noodles before ripening at 55C for 60min (same as the first batch). After coating I exposed and developed in D-23 as before and the plates looked AMAZING in the developer, I was seeing the extra density I'd hoped for with negligible fog. Washed briefly in water, placed into TF-2 fixer, and...
All of a sudden the plate turns completely black?!
Thinking perhaps I'd mixed the fixer incorrectly, I tried again with Formulary TF-4... exact same issue.
The resulting plates do have some variance in density, as in I can still make out the step wedge when placed on a light box or held up to a bright light, but to the eye they look pure black. I certainly expected some fog with the added sensitizers, but am confused about why it's appearing all at once and not in the developer, only in the fixer.
Could it be pH related? Both TF-2 and TF-4 are alkaline fixers. I may make up a batch of acid fixer to try next, but any other ideas in the meantime?
But of course I couldn't leave well enough alone and decided to experiment a bit with my second batch, because SPEED. I didn't have ammonium thiocyanate on hand to make Steigmann's solution, but understood that hypo could be substituted, so attempted to do the molar math and ended up with roughly:
6 drops 2% sodium thiosulfate
6 drops 0.1% gold chloride
Per recipe of emulsion, mixed into 5ml of ethanol along with:
2 drops 10% potassium bromide
14 drops 0.5% erythrosine
The solution was then mixed into the washed noodles before ripening at 55C for 60min (same as the first batch). After coating I exposed and developed in D-23 as before and the plates looked AMAZING in the developer, I was seeing the extra density I'd hoped for with negligible fog. Washed briefly in water, placed into TF-2 fixer, and...
All of a sudden the plate turns completely black?!
Thinking perhaps I'd mixed the fixer incorrectly, I tried again with Formulary TF-4... exact same issue.
The resulting plates do have some variance in density, as in I can still make out the step wedge when placed on a light box or held up to a bright light, but to the eye they look pure black. I certainly expected some fog with the added sensitizers, but am confused about why it's appearing all at once and not in the developer, only in the fixer.
Could it be pH related? Both TF-2 and TF-4 are alkaline fixers. I may make up a batch of acid fixer to try next, but any other ideas in the meantime?
