Milkyness in dcg
Posted: Sat Feb 23, 2013 10:06 am
I'm using a post-exposure bath which works well, as follows:
Part 1: Sodium Metabisulfite (1% solution in water)
Part 2: Aluminum Sulfate (0.2% solution in water)
Before use, I mix equal volumes of 1 and 2, and soak the exposed plate for about 2 minutes.
This system has a number of advantages. First, these chemicals are cheap and comparatively pleasant to use. Second, the concentrations can easily be changed to suit your needs. The sulfite appears to promote reduction, and the alum provides some bias hardening. The time in the bath can be changed also, of course.
Thanks to John Pecora and Jeff Blyth for your research.
Note: As I recall, Jeff had mentioned to me that potassium metabisulfite should probably work in a similar way compared to the sodium. There are many types of "alum" but I would suggest trying the Aluminum Sulfate first.
Part 1: Sodium Metabisulfite (1% solution in water)
Part 2: Aluminum Sulfate (0.2% solution in water)
Before use, I mix equal volumes of 1 and 2, and soak the exposed plate for about 2 minutes.
This system has a number of advantages. First, these chemicals are cheap and comparatively pleasant to use. Second, the concentrations can easily be changed to suit your needs. The sulfite appears to promote reduction, and the alum provides some bias hardening. The time in the bath can be changed also, of course.
Thanks to John Pecora and Jeff Blyth for your research.
Note: As I recall, Jeff had mentioned to me that potassium metabisulfite should probably work in a similar way compared to the sodium. There are many types of "alum" but I would suggest trying the Aluminum Sulfate first.