Monday, June 28, 2010

90 Second Reagent Formula Used Below

Here is one reagent formula that I got to work with TMY and Efke. As mentioned before, it is like Quaill's recipe, and with the substitution of lye it is like 55 reagent.

I mix 4 ml HC-110, 15ml soapy ammonia which is ammonium hydroxide 5% in water,  and 3 ml Ilford Rapid Fixer concentrate together. The HC-110 is viscous, so I add that in first, then ammonia, then the fixer.  To that I mix in a gram or so of dry sodium sulfite. This is supposed to prevent sludge from becoming too extensive. Total development time = 2 minutes at 70F.  This is more than enough to process one sheet of 4X5 film. Measure the pH and it should be nearly 10.

Afterward I use a standard hypo clearing agent such as more sodium sulfite mixed according to T55 instructions. You only need a little in water, and you can get by with none at all if you wash the negative thoroughly.

The soapy ammonia wets faster and acts like a photo-flo agent, which you definitely need if you are in the field and want the negative to dry fast without streaks.  Another way I have done this is to also substitute the ammonia with 5 grams of sodium hydroxide, but if I do, I mix it in a stainless bowl as it gets hot.  The final pH should be 9.4. Sodium hydroxide can be hazardous. Here are typical pH strips, which are needed to properly tune the reagent.

I do not recommend that you mix these chemicals unless you have adequate training, wear a face shield and gloves, and have proper equipment. Absolutely do not get any chemicals on your hands or in your eyes. Caustic materials such as sodium hydroxide, lithium hydroxide and ammonium hydroxide are common in many detergent and even food processing formulas, but usually in very dilute, weak concentrations. Here I am using more concentrated forms.

This is not our final formula as there is considerable change in the rate of development when used with a DTR process, but it will produce a negative in a hurry.  There is a long experiment planned that would zero in on the right time, mix and receiver sheet that has been discussed at length in this blog. Also the above formula may be apparent to anyone who has read the earlier posts.


awldune said...

What kind of lifetime would you expect for this "working solution"? Does it stay good for a couple of days?

Bob Crowley said...

Yes, at least a week anyway. I have more dilute forms of it that have been bottled with little or no air for 5 or 6 weeks. The odds are this can be made to last a very long time, with proper preparation, sealing and storage.