Historical Context

Mordançage (from French mordancer, to etch or corrode) was developed by Jean-Pierre Sudre in France around 1960, building on earlier experiments with bleach and etch techniques. The process creates surreal, dreamlike images by selectively lifting and veiling the shadow areas of conventional silver gelatin prints.

The technique gained renewed interest in the 1990s and 2000s as photographers sought alternatives to digital manipulation for creating otherworldly imagery.

Chemistry

Bleach Bath (Copper Chloride Formula)

Component	Amount
Copper chloride	25 g
Potassium bromide	25 g
Concentrated hydrochloric acid	25 ml
Water	1 litre

Alternative Bleach (Dichromate Formula)

Component	Amount
Potassium dichromate	10 g
Concentrated sulphuric acid	10 ml
Water	1 litre

Warning: Both formulas are hazardous. The dichromate formula contains carcinogenic hexavalent chromium.

Procedure

Print preparation: Start with a well-fixed, thoroughly washed fibre-based silver gelatin print. Prints should be slightly darker than normal as the process reduces density.
Bleaching: Immerse the dry or slightly damp print in the bleach bath. Observe carefully—the shadow areas will begin to lift and veil within 30 seconds to several minutes.
Control: The longer the bleach, the more dramatic the effect. Remove when desired effect is achieved. Different parts of the image can be masked or treated differently.
Water rinse: Rinse briefly in water to stop the bleaching action.
Manipulation: This is the creative heart of mordançage:
- Leave veils intact for ghostly effect
- Push veils aside with water stream or brush
- Remove lifted gelatin completely
- Refix to stabilise (optional)
- Combine with other processes
Redevelopment (optional): The bleached image can be redeveloped in standard print developer to add back density in selective areas.
Final wash: Wash thoroughly (30+ minutes) to remove all chemistry.
Drying: Air dry or dry with care—lifted gelatin areas are fragile.

Creative Possibilities

Mordançage offers endless manipulation options:

Technique	Effect
Veils left intact	Ghostly, ethereal shadows
Veils pushed aside	Revealed paper texture
Veils removed	Sharp tonal breaks
Multiple bleaching	Layered effects
Selective masking	Localised treatment
Redevelopment	Recovered density in areas
Toning after	Colour variations

Troubleshooting

Problem	Likely Cause	Solution
No lifting	Bleach exhausted; wrong paper	Fresh bleach; fibre paper only
Too much lifting	Over-bleaching	Reduce time; dilute bleach
Highlights affected	Bleach too strong	Dilute; shorter time
Fragile veils	Inherent to process	Handle carefully; document with photography
Inconsistent results	Variable print density	More consistent printing

Safety

Chemical	Hazard	Precautions
Copper chloride	Toxic; corrosive	Gloves; ventilation
Potassium bromide	Low toxicity	Standard precautions
Hydrochloric acid	Corrosive; toxic fumes	Fume hood or excellent ventilation; gloves; eye protection
Potassium dichromate	Carcinogenic	Avoid if possible; full protection if used
Sulphuric acid	Highly corrosive	Extreme caution; proper PPE

This is one of the more hazardous alternative processes. Work in a well-ventilated area with appropriate safety equipment. Consider the copper chloride formula as it avoids carcinogenic dichromates.

Print Archival Considerations

Mordançage prints may have compromised archival properties:

Lifted gelatin areas are physically fragile
Residual chemicals may remain in paper
Consider the prints as unique objects requiring careful storage
Document important work photographically

Mordançage

Image characteristics

Key chemicals