Ok, if others have contributions in terms of the working strength life time, I would gladly hear them...
Tom's detailed answer with recipes raises another question though:
- How do these WT/CT developers actually work???
I mean: silver is silver? :o
How can a developer actually change the "tone" of the print??? What is the chemistry or physics behind their workings? Is it a change in the size or shape of the silver particles? Or are there actually more substances deposited than just plain metallic silver in a silver print??
The image tone of a print paper is mostly determined by the emulsion design and thus by the paper manufacturer. Print Exposure and development can modify the image tone and color to a degree by increasing and decreasing image fog (through the use of restrainers - potassium bromide and/or benzotriazole) and by changing image contrast (via developer dilution and activity changes).