Toning is a technique to change cast of black-and-white prints and create a toned monochromatic image. During the process, metallic silver particles are replaced by silver compound. Different toning processes give different colors to the final print. It usually works better on fibre-based paper than resin-coated ones.
Caution : it is a toxic process, ventilate the room and wear rubber gloves.
Toning is interesting for two reasons:
.Change the colour cast
. Increase chemical stability and archival quality (longevity) of the print over years (sepia, gold toning) or decrease stability (iron, copper)
Split Toning pdf
Split toning is a technique to give different colors to the highlights and the shadows, by using two toners one after the other. Different combinations of toners will create different results.