Friday, March 12, 2010

The Trouble with Reagent A3



Monobath A3 is something close to the reagent used in 55. While not yet as viscous, the pH, ratio of developer to solvent and hypo, and the processing times are converging. This is another 2 minute brew. You can see what we were concerned with in this intentionally underexposed negative shot of a black subject. TMY exposed at 400 off the surface of the blacker than 18% camera.

8 comments:

Anonymous said...

you call this bad? I kind of like it. Vintage and cool/old.

gerald said...

me too...
(though i have to admit i don't really get what you're pointing at, but i have the flu and that makes everything nebulous.. even my english)

(but.. what a beauty of a camera :))

Bob Crowley said...

Chemical fog is what's wrong, perhaps a cure for the flu? Feel better.

Aaron Muderick said...

any chance there is an actual thickener in the reagent to make it thick enough for spreading properly? A Min-u-sil ground silica should be inert, will have a thickening effect, and is cheap. At the right particle size, I don't think abrasion will be a problem. Thoughts?

Bob Crowley said...

Hi Aaron!

Corn starch seems to work and Metamucil powder too. Goopy. I am not familiar with the material you mention - where can I get a sample?

Or maybe some more temp change putty for some color?

Seriously, I will try it as long as I can mix it with the sodium hydroxide without a fire. The developer-caustic soda-solvent mix is rather stiff but it doesn't gel and hasn't the viscous flow we are familiar with.

Bob Crowley said...

Oh and I am going to completely switch over to the Efke 4x5 soon for experiments as soon as I do have a thick enough reagent to squeegee against a receiver paper. That will cut the development time to seconds as the Efke has a very thin emulsion and no topcoat.

Anonymous said...

The second shot looks bluish here. Very nice Bob. Was that intentional?
ML

Bob Crowley said...

No it looks like pollution from using the scanner in the wrong mode or something, but I like it. Thanks.