In photography, toning is a method of changing the color of black-and-white
photographs. In analog photography, toning is a chemical process carried out
on silver-based photographic prints. This darkroom process can not be done
with a color photograph. There is debate as to whether a toned black-and-white
photograph should be considered to still be black-and-white, as simply being
monochromatic is not a sufficient condition for an image to count as
black-and-white. The effects of these processes can be emulated with software
in digital photography. Chemical toning
Most toners work by replacing the metallic silver in the emulsion with a
silver compound, such as silver sulfide in the case of sepia toning. The
compound may be more stable than metallic silver and may also have a
different color or tone. Different toning processes give different colors
to the final print. In some cases, the printer may choose to tone some parts of
a print more than others. Toner also can increase the range of
shades visible in a print without reducing the contrast. Selenium toning
is especially effective in this regard. Some toning processes can improve the
chemical stability of the print, increasing its potential longevity.
Other toning processes, such as iron and copper toners, can make the print less
stable. Many chemical toners are highly toxic. It is extremely important that
the chemicals be used in a well ventilated area. Rubber gloves and face
protection should be worn when handling them. Some toners contain chemicals that
are carcinogenic. = Selenium toning=
Selenium toning is a popular archival toning process, converting metallic
silver to silver selenide. In a diluted toning solution, selenium toning gives a
red-brown tone, while a strong solution gives a purple-brown tone. The change in
color depends upon the chemical make-up of the photographic emulsion being
toned. Chloro-bromide papers change dramatically, whilst pure bromide papers
change little. Fibre-based papers are more responsive to selenium toning.
Selenium toning may not produce prints quite as stable as sepia or gold toning.
Recently, doubts have surfaced as to the effectiveness of selenium toner in
ensuring print longevity. In most applications, selenium toning
was not used for its sepia or red tone by fine art photographers. In fact it
was used for the opposite of those effects
Agfa Portriga Rapid and Agfa Record Rapid had a brownish green tone.
Depending on strength of selenium tone mixed to water, a three to four minutes
tray bath, with continuous circulation, removed the brownish green tone and
provided a deep rich black. Higher concentrations of selenium toning
and longer tray baths produced the red to desired effect. 99% of vintage prints
in museums, sold at galleries and auction that are selenium toned, are
toned, to remove the brownish green tone and provided a deep rich black,
Most reported tests over the years in tech photography publications had
selenium toned prints at twice the longevity of untoned prints.
= Sepia toning= Sepia toning is a specialized treatment
to give a black-and-white photographic print a warmer tone and to enhance its
archival qualities. Chemicals are used to convert the metallic silver in the
print to a sulfide compound, which is much more resistant to the effects of
environmental pollutants such as atmospheric sulfur compounds. Silver
sulfide is at least 50% more stable than silver.
There are three types of sepia toner in modern use;
Sodium sulfide toners - the traditional 'rotten egg' toner;
Thiourea toners - these are odorless and the tone can be varied according to the
chemical mixture; Polysulfide or 'direct' toners - these
do not require a bleaching stage. Except for polysulfide toners, sepia
toning is done in three stages. First the print is soaked in a potassium
ferricyanide bleach to re-convert the metallic silver to silver halide. The
print is washed to remove excess potassium ferricyanide then immersed
into a bath of toner, which converts the silver halides to silver sulfide.
Incomplete bleaching creates a multi-toned image with sepia highlights
and gray mid-tones and shadows. This is called split toning. The untoned silver
in the print can be treated with a different toner, such as gold or
selenium. Fred Judge FRPS made extensive use of
sepia toning for postcards produced by the British picture postcards
manufacturer Judges Postcards. = Metal replacement toning=
Metal replacement toners replace the metallic silver, through a series of
chemical reactions, with a ferrocyanide salt of a transition metal. Some metals,
such as platinum or gold can protect the image. Others, such as iron or copper
may reduce the lifetime of the image. Metal replacement toning with gold alone
results in a blue-black tone. It is often combined with a sepia toner to
produce a more attractive orange-red tone. The archival Gold Protective
Solution formula uses a 1% gold chloride stock solution with sodium or potassium
thiocyanate. It is sometimes used to split tone photographs previously toned
in selenium for artistic purposes. = Dye toning=
Dye toners replace the metallic silver with a dye. The image will have a
reduced lifetime compared with an ordinary silver print.
Digital toning Toning can be simulated digitally,
either in-camera or in post-processing. The in-camera effect, as well as
beginner tutorials given for software like Photoshop or GIMP, use a simple
tint. More sophisticated software tends to implement sepia tones using the
duotone feature. Simpler photo-editing software usually has an option to
sepia-tone an image in one step. Examples
The examples below show a digital color photograph, a black-and-white version
and a sepia-toned version. The following are examples of the three
types using film: See also
Color grading Cyanotype
Film tinting Grisaille
List of software palettes — Color gradient palettes section
Monochrome Platinotype
Selective color References
External links Chemical toning:
(Book) Photographic facts and formulas Many various toners(p. 216)
(Book) All about formulae for your darkroom Selenium, indirect sulphide
toning, red chalk, blue and green tones (Book) Kodak Chemicals and Formulae
Selenium, sulphide-selenium and other toners
Ilford: Toning prints Sepia toning in a developing tray.
Digital "toning": Sepia Toner Application to convert
digital images Sepia Effect Vintage sepia effect in
Easy Photo Effects Sepia toning in Adobe Photoshop
Sepia toning in the GIMP Sepia toning in Java