Articles

Sepia toning

01/04/2020
Some notes on sepia toning of darkroom enlarging papers.
Sepia is one of the most flexible chemical toners for black and white darkroom photography, 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 usually only partially bleach and partially tone my prints. Using diluted solutions of both the bleach and toner I find the process is easier to control and the results more predictable. Bleaching an image away completely to a straw colour, and then sepia toning will result in an overall sepia or dark brown image when the print is toned to completion. I am not fond of that type of totally brown toned sepia print, preferring instead to tone just the high lights and the mid-tone areas followed by a brief selenium toning. This method when used on a neutral or cold tone paper results in a final print that has the contrast of warm highlights and cold toned shadow areas.

Chlorobromide papers such as Ilford MGWT are superb papers and excellent ones to print with, but I find that when sepia toned they become too colourful for my own taste. My preference is to print and tone with neutral tone papers such as Ilford MGIV Classic, which is my current standard paper of choice. To arrive at a degree of control and to produce constant repeatable results I made a variety of tests with this paper altering the bleach and toner times, as well as the dilution and mixing ratio of the sepia toning components. As a result of these tests I now have a number of set toning routines to choose from, that I find are repeatable and with each one giving a subtle range of tones and colours. See Sepia toning Pt2.

For my sepia toning I mix small amounts of raw chemicals to create three stock solutions.
Potassium ferricyanide bleach, Thiourea and Sodium Hydroxide. Then depending on the colour I want to achieve in the print, I mix a toning bath to the appropriate ratio.
i.e. For yellow tones it would be 5-1 Thiourea - Hydroxide mix, or 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 also 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