Colour Space
Definition
A defined mapping between numerical RGB values and real-world colours. sRGB is the web default with a smaller gamut; Adobe RGB covers a wider gamut; ProPhoto RGB is used in high-end workflows. Conversion between spaces alters pixel values and can mask noise patterns.
- Web default
- sRGB, smaller gamut
- Wider gamut option
- Adobe RGB
- High-end workflow option
- ProPhoto RGB
- Forensic risk
- Conversion can mask noise patterns
Common questions
Why does colour space conversion matter for forensic image authentication?+
Converting between colour spaces remaps pixel values through interpolation, and this can smooth out or alter subtle sensor noise patterns used for source camera identification, so examiners work from the original colour space wherever possible rather than a converted copy.
How is colour space different from bit depth?+
Colour space defines which real-world colours a given set of numbers represents, while bit depth defines how many distinct values are available to represent them, so two images can share the same colour space but differ in precision, or share bit depth but map to different actual colours.
Related terms
- Bayer CFA
- A colour filter array arranged in a repeating 2×2 mosaic of red, green (×2), and blue filters over the sensor. Each photosite...
- Demosaicing
- The algorithm used to interpolate full-colour pixel values from the single-channel raw sensor data. Common methods include bilinear interpolation, gradient-based algorithms (AHD,...
- Fixed-Pattern Noise (FPN)
- Any repeatable, spatially correlated noise in an image sensor, as opposed to random shot noise. PRNU and DCNU are both forms of...
- JPEG Compression
- A lossy codec that divides an image into 8×8 pixel blocks, applies the discrete cosine transform, quantises the coefficients, and entropy-codes the...
- RAW Format
- A camera capture format that records unprocessed sensor data, preserving all original exposure and colour information. RAW files are preferred over JPEG...