Re: Selenium "printing" (?) There is no such thing as selenium printing, there is/was a toner called selenium toner. Toners are chemical baths that are applied to (analog) prints after they are developed, fixed and thoroughly washed. There are specific toners for specific papers. The toner alters the image tone of the paper from neutral black and white to various warmer and cooler tones of brown, sepia, or even blue. Some toners involve bleaching out the print and then re-developing it in the toner, others were simply one step processes. Brown toner, sepia toner and similar formulations imparted a warmer somewhat yellowish tone where selenium toning resulted in a somewhat cooler brown and sometimes a reddish or maroon hue. Selenium toner also acted as an intensifier so prints that were planned for selenium toning need to be somewhat lighter as darkening occurred in the toning bath Toned prints when properly washed are part of the archival process. The ultimate toner was Nelson Gold Toner, made with actual gold chloride. It makes for a golden tone on chloride type printing papers.

If you wish to simulate any of theses effects in digital print, you have to start with a monochromatic image and work with the white balance sliders until you replicate the desired image tone. This action is carried out in post-processing.