Moersch MT4 is a polysulfide toner that gives warm-brown to red-yellow image tones when used directly. It is also possible to use this toner indirectly (after bleaching), although you should only bleach for a very short period. After toning, the bleached areas will show a red-yellow image tone.
This toner has a long shelf life and a high capacity. Dilutions of up to 1+30 can be used for several months. Only after heavy usage (more than 50 prints of 24x30 cm per litre 1+20) you will notice a color shift to pure yellow tones while the toning process gets slower. This is due to a decline of the pH-value. You can replenish the toner by adding an alkali like soda or by adding some drops of toner stock solution.
Dilution: for normal use 1+20 to 1+100; for multicolored image tones dilute up to 1+500 or even higher.
Caution: polysulphide toner still works in extremely high dilutions! Toning will go on while you rinse. This is particularly obvious on warmtone emulsions. To stop the toning process you can use a 10% sulphite bath. Use it after a short rinse – by changing the water in the dish a couple of times. As an alternative to the sulphite solution, you can also use the Moersch washing aid (diluted between 1+1 and 1+3).