Saturday, January 30, 2010
Donald Qualls' successful monobath posted on phot net
IMAGES in R3
I have highlighted an interesting comment which needs to be tested.
And Bravo to Donald!
Donald Qualls , Feb 29, 2004; 08:18 p.m.
Monobath from commercial chemicals: success!!
400TX 135, souped ten minutes, 75 F.
16 ml HC-110 USA concentrate
50 ml household ammonia (ammonium hydroxide, 5% solution)
10 ml Ilford Rapid Fixer concentrate
water to make 256 ml
Mixed by adding most of the water to the HC-110 concentrate, then ammonia, then fixer, then remainder of water to make up volume. Heated to 75 F in an external hot water bath.
IMPORTANT: Be certain the ammonia used is a 5% concentration. Test it first using an ammonia hydrometer available through ebay or Amazon.
Result: normal appearing negatives, within approximately 1 stop of rated speed at worst. I won't know for certain until I can scan them (they're drying now, probably won't get them scanned tonight), but to my eye contrast range appears normal and low light details are preserved -- I intentionally shot at a wide range of exposure, from about +2 to -2 stops, to test whether the latitude of the 400TX would be preserved, and it appears it was; there is considerable detail in a shot taken with a simple camera (most likely f/11, 1/100) in a grocery store aisle by available light, a situation that normally demands f/2.8 at 1/30 with ISO 400, give or take one stop.
Worthy of note that the concentrates used have excellent keeping properties, and household ammonia is a common cleaning supply available worldwide. Even accounting for use of distilled water both for mixing and a multi-change stand wash, total cost per film is about $1.25; if tap water can be used for wash, cost is more like sixty-five cents per film in 35 mm -- 120 would be about double this, since twice the solution is required for the same film area (unless one masters back-to-back loading). Film processed this way should be archivally stable if properly washed; even at this 1:24 dilution, the fixer has about 200% capacity over that needed to fix 80 square inches of film per above batch of monobath.
I'm pretty happy with this, as you can probably tell."
Posted by Bob Crowley at 6:26 AM