Toning to completion means full color shift. This will vary depending upon paper. If you do not want color shift, or as little as possible, then "permanence" may be compromised (however defined or desired). Toning to color shift in terms of timing, which may increase contrast and "sharpen" the image, is somewhat a matter of trial and error, depending on:
Originally Posted by Carina
- paper type
- toner dilution
- degree of toner exhaustion
I use selenium toner for minimal color shift. I normally do this with all prints at the end of the day. One needs to watch the first toned print for a color change, whereupon it is quickly withdrawn, taking note of the time. The rest (same paper) can be batched at the noted time. I have noticed, in my lab, that the time to color shift increases by approximately 30 seconds, each day as toner sits around and becomes both exhausted and/or oxidized. I toss it when toning times become too lengthy and then mix fresh (KRST –> 1:20).