Quote Originally Posted by Carina View Post
I've read lots of recommendations regarding the toning in selenium or gold that say that in order to achieve archival permanence it is necessary to "tone to completion". Since I'm mostly interested in image permanence and do not want too much color shift, I've bought a bottle of Tetenal Gold toner. How do I make sure that the toning has been taken to completion? The color shifts slightly rather quickly, and then how long should I keep the prints in toner? Does this time increase as the toner gets exhausted?
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:

  1. paper type
  2. toner dilution
  3. 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 One needs to watch the first toned print for a color change, whereupon it is quickly withdrawn, taking note of the time.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).