Ammonium halides only ClBr emulsion

[di de]

I'm not a chemist nor a photo engineer, I just play around with stuff... so I decided to try a ClBr emulsion using ammonium chloride and ammonium bromide (intead of NaCl and KBr I've used previously)

Below are two contact lith prints for comparison, the ammonium halide emulsion turned out extremely warm.

 

[dwross]

Very interesting! May I ask what developer you used? And, were the exposure times the same?

 

[di de]

Hello Denise,
Everything was roughly the same except the halides, but I used the same weight of halides in the two cases, so considering molar mass, there was more halide excess with ammonium.
The developer was as follows:
For 1L of water
1g Hydroquinone
1g Sodium sulfite
3g Sodium hydroxyde
1g Potassium bromide
But lith developers don't behave as "regular"" developers, see: https://unblinkingeye.com/Articles/Lith/lith.html

 

[dwross]

Thank you for sharing the information. It's really fun to follow your work. Which do your prefer?

 

[di de]

I would prefer a mix of the two... (I'm working on it, and some other ideas, I'll keep you informed if I get some interesting results)

 

[RauschenOderKorn]

The byproduct in your emulsion is ammoniumnitrate. That - on its own - is no problem. But you should make sure that you do not accidentally set it off.

 

[RauschenOderKorn]

I like the warmer tone, it also seems to have a little less contrast than the picture you show us for comparison.

 

[di de]

As I said yesterday, I would have preferred something between the two examples shown above, so I followed my intuition and made an emulsion with ammonium chloride (NH4Cl) and potassium bromide (KBr), ratio 2:3, don't ask me why, it was only a feeling, nothing scientific...
And I got just what I expected, deep blacks with warm middle tones as you can see below (even if the scan can't show the actual tones of the print)
I think this formula will be a keeper !

RauschenOdernKorn, I used about 1g NH4Cl and NH4Br, so I presume there is no risk that I could blast my darkroom off...

 

[Photo Engineer]

Very impressive result.

PE

 

[di de]

The three emulsions side by side, from left to right: NH4Cl & NH4Br, NH4Cl & KBr, NaCl & KBr

 

[di de]

Thank you PE !

 

[di de]

Now I'm starting to play with toners with this emulsion.

Below you see a lith print developed in high bromide content lith developer, the left part is untoned and shows a typical green cast, the right part is toned in selenium 1:9 for 20 minutes and showed a deep red wine tone when wet that mostly vanished when dry.