simple monobath for agfa multicontrast paper?

[yulia_s_rey]

hello, I was just ask by a client if we can provide a minutero (sp.) for a cuban themed event. building the postcard camera will be fun, but as far as processing does anyone know if there is a "decent" monobath recipe/soup that would be good for agfa multicontrast classic paper? As a child I remember seeing these photographers with homemade cameras on almost on every city plaza throughout spain, although I never got a chance to look what was inside.

 

[Ian Grant]

Back in the 1970's I researched and designed Monobaths for commercial use with a specialist emulsion, much of the initial work was done with resin coated papers and it was suggested that we market a Monobath for papers. However I found that the formula needed tweaking to suit different emulsions to get the best results.

i don't have access to my notes at present but you could start with Crawley's FX-6a, although it's a film developer it does work well with papers as well, but may need tweaking slightly:

Crawley FX-6a Monobath

Sodium Suphite 50.0 grams
Hydroquinone 12.9 grams
Phenidone 1.0 gram
Sodium Hydroxide 10.0 grams
Sodium Thiosulphate 90.0 grams
Water to 1 litre

Ian

 

[Nicholas Lindan]

You need reversal paper. For discussion (there was a url link here which no longer exists). Works at ISO 3 - with an f4.5 lens (152mm Ektar) a sunny exposure of 1/25th of a second should be possible with a 4x5 print size.

As to monobath print developer, you may be on your own. Expect a monobath process to take 2-3 times that required to 'develop to completion'. You may be better off with a stabilization process.

More information on postcard cameras here http://www.vintagephoto.tv/mandelette.shtml

 

[yulia_s_rey]

thank you Ian I can easily get the extra chemistry I need since B&H is just a short train ride away. actually Nicolas brought up a great point, I originally was thinking of going the "old school" route of re-photographing the negative, but this may now be an issue since the monobaths take longer. I'd like to give the event goers a print in about five minutes (while they get out of the costumes & masks they'll have available on the "set")
great link! that is one big & beautiful camera! after looking into the Chicago Ferrotype Co.'s other cameras I also like the "Wonder Photo Cannon"

 

[Gerald C Koch]

Anyone contemplating mixing a monobath should read Grant Haist's book "The Monobath Manual."

Phenidone is unstable in alkaline solution, the higher the pH the faster the rate of hydrolysis. Crawley's formula should be made up shortly before use and may not keep very long. A substituted phenidone like Dimezone S would be a better choice.

 

[Ian Grant]

Gerald, there's a few myths about Phenidone because it's a generic family of developing agents and there are variants so much of what's been written in some books should be taken with a piece of salt.

Phenidone keeps extremely well in powder form, certainly over 45 years, which is not what's written by some authors, it keeps reasonably well in alkali solution. The myths come from Ilfords early experiences from the 40's to very early 1950's, but by the time it was in commercial production (1953/4) the Phenidone being sold was very much more stable in alkali solution.

I use Phenidone in almost all my developers with no stability issues, my original large batch was (bought around 1976) was stamped with Ilfords 1962 code, I only finished it 3 or 4 years ago but there was no differences whatso ever when I switched to newer Phenidone.

Haist's book misses out much of the other parallel research taking place elsewhere as it hadn't been (or was) published when Haist wrote his book but it's a place to start. Gerge Wakefield wrote a good review of the then current research into Monobaths in a British Journal of Photography article around 1976'ish.

My own experience was that Phenidone kept well in FX-6a or equivalents, we kept stock solutions on the shelf for months with no deterioration.

Ian

 

[Gerald C Koch]

Hi Ian,

I based my comments on what Mason says in "Photographic Processing Chemistry, 1966." He does mention Ilford's own reseach into this problem. As part of a graduate chemistry course in instrumentation I devised an experiment to measure the rate of hydrolysis. I personally now use Dimezone S exclusively.

 

[yulia_s_rey]

thanks for the tips everyone! I was able to give a nice pitch today my client is very happy and can't wait. I will post some snaps of the camera as soon as its built.

 

[yulia_s_rey]

pics coming soon!