Information

Sepia toning

16/04/2020
Some notes on sepia toning of darkroom enlarging papers.
The toning of a black and white image can be done to convey emotion, or enhance the mood and atmosphere of the picture. With a darkroom print, it is can also be done for archival permanence. Sepia is one of the most flexible chemical toners, it is easy to work with and depending on the paper used it can give a range of subtle or intense colours.

For my own work I only partially bleach and partially tone my prints. Using diluted solutions of both bleach and the toner, the process is easy to control and the result are predictable. Bleaching the print to completion, and removing the silver image entirely before toning will result in an overall sepia or dark brown image. I am not fond of this type of completely sepia toned print. My preference is to partially bleach and tone just the high lights and maybe into the mid-tone areas of a print. This gives a final print with a contrast of warm highlights and cold toned shadow areas.

Chlorobromide papers such as Ilford MGWT are superb papers and excellent to print with, but I find that when toned they become too colourful for my own taste. Recently I have made Ilford MGIV Classic my standard paper. After some fairly extensive testing, varying the bleach and toner times as well as the dilution and mixing ratio of the sepia toner. I have settled on a few basic toning routines, that I find are repeatable and give a subtle range of tones and colours and give me the results I look for in my final prints.

For my sepia toning I mix small amounts from raw chemicals to create three stock solutions. Potassium ferricyanide bleach, Thiourea and Sodium Hydroxide. Then depending on the colour I want to achieve, I mix a toning bath to the appropriate ratio. i.e. for yellow tones it would be 5-1 Thiourea - Hydroxide mix, and for a more red/brown tone it would be 1-5 Thiourea - Hydroxide. The image tone is dependent on both the bleach and toning times. The final colour can be further modified after sepia toning with selenium toner.

Bleach stock solution
10gms Potassium ferricyanide
5gms Potassium Bromide
Mixed in 100mls cold water

Toning stock solutions
A 10gms Thiourea in 100mls hot water (40c)
B 10gms Sodium Hydroxide in 100mls cold water.

Ratio for colour control
Mixed from Stock toning solutions.
For yellow tones mix 5 parts A Thiourea to 1 part B Hydroxide
eg: 50mls A Thiourea and 10mls B Hydroxide in water to make 1 litre.

For brown tones mix 3 parts A Thiourea to 3 part B Hydroxide
eg: 30mls A Thiourea and 30mls B Hydroxide in water to make 1 litre.

For red/brown tones mix 1 parts A Thiourea to 5 part B Hydroxide
eg: 10mls A Thiourea and 50mls B Hydroxide in water to make 1 litre.

Working practice
This is an example of my times and dilutions from the stock solutions to achieve a warm yellow highlights with Ilford Classic fibre paper.

0008 250
 


Bleach
15mls of stock bleach solutions in 1 litre of water

Toning
40mls of stock solutions A (Thiourea)
10mls of stock solutions B (Hydroxide)
mixed together in 1 litre of water.

Bleach 60-90sec
Wash 10mins
Tone 8-10mins
Wash 10mins
Selenium tone 1+20 60-90secs.
Wash 30-45mins

A example of a more red/brown tone image.

0032 250
 


Bleach
15mls of stock bleach solutions in 1 litre of water

Toning
10mls of stock solutions A (Thiourea)
40mls of stock solutions B (Hydroxide)
mixed together in 1 litre of water.

Bleach 60-90sec
Wash 10mins
Tone 6-8mins
Wash 10mins
Selenium tone 1+20 60-90secs.
Wash 30-45mins