I only selenium tone my prints to achieve just a hint of warmer tone.
I selective bleach occasionally to bring out highlights in the print. I use a ferricyanide/bromide rehalogenating bleach. Below is my method, cut and pasted from my personal darkroom handbook.
Note: this technique turns silver into invisible silver bromide that needs to be fixed away.
1. Prepare a dilute ferricyanide/bromide solution of about 1 to 2% by adding 10 drops of 10% ferricyanide solution and 30 drops of 3.2% potassium bromide solution (I have these on hand always) to 10ml water (or mix the appropriate dilution in larger quantity, basic solution is 1g pot. ferricyanide and 1g pot. bromide / liter). This solution is a starting point and can be strengthened or weakened as needed.
2. The print needs to be fairly free of fixer, i.e., well-washed before using this technique. 15 min.or so in water should do the trick.
3. Lay the print on an angled work surface, (e.g. the bottom of a flat-bottomed tray). Position the print so that the run-off does not flow over areas of low density that should not be bleached. Working with the running water hose in your left hand, apply the bleach locally with a brush or cotton swab (Chinese calligraphy brushes work well. Don't use brushes with a metal ferule, as this can cause unwanted reactions and staining). Work from bottom to top and monitor the bleaching carefully. It is very important to keep the water running on the print directly below the area being worked on to prevent streaking by the run-off and to keep the water hose moving to keep the bleach from being directed down the edge of the water stream and causing streaks there. Before the desired tone has been reached, rinse well. It is better to build up to the desired tone slowly to prevent over-bleaching, keeping in mind that the bleaching continues for a while after rinsing. Be careful that the bleach is not working too quickly. If so, rinse the print thoroughly and repeat with a weaker bleach solution. Overbleaching can cause split toning!
4. When the desired tone has almost been reached, rinse the print thoroughly to remove all the bleaching agents before fixing.
5. If the bleaching process goes to far, the print can be returned to the developer if bleaching has gone too far, but this will result in a different size and shape of silver grain being formed from the original development, which will tone differently. If redevelopment is necessary, keep toning to a minimum.
6. The print now needs to be fixed to remove the silver bromide produced by the bleach. Give it a full-time fix in the second fixing bath (i.e., 2 minutes in fresh fixer)
7. Wash and dry as usual.
Have fun,
Doremus
