Sodium Thiosulfate "Plain Fixer"

[john_s]

I am aware of all of this.

It probably depends on the stop/wash between the developer and fixer, but if the potassium is in high enough concentration in the developer it can poison the fix or drastically slow it down.

Being aware of it, I have run some limited tests to show myself that it can be used in limited quantity in developers, but must be used with care.

PE

In that case, for paper, I will review the thoroughness of my rinse between developer and fixer. I'm in the habit of just using water, but I should probably extend the time and perhaps pay more attention to replacing the water more frequently.