What is a photographic emulsion?

A photographic emulsion is a light-sensitive colloid typically made of silver halide crystals dispersed in gelatin. Although technically a suspension of solid particles in a fluid rather than a true liquid-liquid emulsion, the term is standard in photography. This light-sensitive layer is coated onto various substrates like glass, film, paper, or fabric to capture latent images during exposure.

What we know

• Photographic emulsion in silver-gelatin photography consists of silver halide crystals dispersed in gelatin. [2]
• It is technically a suspension of solid particles in a fluid rather than a true emulsion, but the word is customarily used. [2]
• The emulsion can be coated onto substrates such as glass, film, paper, or fabric. [2]
• Photographic processing uses chemical means to transform the latent image captured by the emulsion into a visible and permanent image. [3]

Where to go next

• what caused itHow does photographic processing work?
• a case in pointWhat is photographic paper?
• the bigger pictureWhat is an emulsion in general chemistry?
• whenWhat happened to Kodachrome film processing?
• compared withHow do nuclear emulsions detect particles?
• an unexpected connectionHow do physics experiments use photographic emulsions?Specialized versions called nuclear emulsions are used in particle physics to detect high-energy elementary particles, sharing the same foundational colloid concepts as household film photography.

Sources

• [1]photographic emulsion (Wikidata Q355549) · CC0 1.0
• [2]Photographic emulsion · CC BY-SA 4.0
• [3]Photographic processing · CC BY-SA 4.0
• [4]Photographic paper · CC BY-SA 4.0
• [5]Emulsion · CC BY-SA 4.0