Thanks for posting this. I'm sure many will find it useful.
For me, however good this information is to know, I still prefer to tone each image to the amount of image tone change that best compliments it. For those prints that only need enhanced D-max, maybe the "cookbook method" will work well, but for me, toning is part of the creative process, and a visual assessment of the print as it is toning is indispensable.
I just toned a batch a couple of days ago and was again struck by the fact that two different images printed on the same paper, same grade and developed for the same time in the same developer needed markedly different toning times to get the best out of the image.
Let me plug again, while I'm at here and posting (and waiting for the print washer), my method of replenishing and saving selenium toner solutions. I never discard my toner, rather, as toning times get too long for comfort, I simply add more of the stock toner solution (I use KRST) to the working solution to replenish it and decrease toning times. The solution is saved, and filtered through coffee filters before each use. The filter removes the black precipitate and any crud that may have accumulated.
I have two gallons of toner solution, strong and weak, that have been going this way for several years. They tone fine and, most importantly, I never, ever have to discard toxic selenium into the environment. Selenium discarded into municipal sewer systems is not removed, rather it (and other heavy metals and toxins that are not degraded biologically) is concentrated in the sludge produced by water treatment plants. I find it much more economical and responsible to replenish.
For those concerned about possible contamination using this method, let me report that my last batch of prints, fixed in Ilford Hypam (2-bath), toned in 4-year-old replenished toner, soaked in HCA for 10 minutes and washed for one hour in an archival washer all passed the residual hypo and residual tests (silver nitrate and sodium sulfide respectively) with flying colors; no stain whatsoever.
Okay, down from the soapbox.
Thanks again Fred for this and all your other very informative videos.