Alkaline stop bath?

[lloyd]

Does anyone know what this product is? I've never heard of an alkaline stop.....

http://www.monochromephotography.com/section233148_83762.html

 

[David A. Goldfarb]

Looks interesting!

 

[RalphLambrecht]

Does anyone know what this product is? I've never heard of an alkaline stop.....

http://www.monochromephotography.com/section233148_83762.html

Most likely an alkaline buffer solution with stable pH value. Maybe they added a restrainer like potassium bromide to suppress development action. A waste of money in my opinion. Use plain water as a stop bath if you prefer acid-free processing.

 

[Photo Engineer]

If you use water, make sure it is running!

Alkaline stop baths are rather easy to formulate but depending on the formula can slow fixing and washing both. The extra halide or other restrainer makes the fix work harder and exhaust more easily. In addition, some can slow washing of the complexes from the coating.

PE

 

[john_s]

From the folks at monchromephotography.com:

"(Suprisingly, an acid stop can give a slight stain in highlight areas, and slightly muddy midtones that do not clear in the fix.)"

I haven't heard this one before. Just as well I use water. Who would want stains in print highlights and muddy midtones, even if they are "slight."

 

[RalphLambrecht]

..."(Suprisingly, an acid stop can give a slight stain in highlight areas, and slightly muddy midtones that do not clear in the fix.)"

I would take this too seriously. I have never experienced this with acid stop baths, and alkaline stop baths have their own set of issues (see PE's post).