Replenishing Toners

[photomc]

Noticed several post that mention Selenium, Viradon, or other toners can be replenished. My question is how do you know how much of the toner concentrate to add to the working solution? Seems like this should be so easy, but I cannot for the life of me figure it out....must be sun spots,

Also, how many of you do this type of replenishment?

Thanks

 

[Jorge]

With fresh toner, measure the time it takes to tone a print to your satisfaction. When it takes twice the amount of time to tone to the same level, is time to replenish.