Assuming an untagged file is broken, when an untagged sRGB image displays perfectly well nearly everywhere.
Colour
Colour tag
Also called color tag, colour space tag or untagged image. Here is what it means, when it changes what you export, and what people get wrong.
ColourRuns on your deviceUpdated 10 August 2026
The short answer
A colour tag is the small piece of metadata in an image file that declares which colour space its pixel values belong to. It can be an EXIF field, a dedicated chunk in the file format, or a full embedded profile. A file without one is called untagged.
Updated
The short version
Colour tag at a glance
| Quick fact | Detail |
|---|---|
| What it declares | Which colour space the pixel values belong to |
| JPEG mechanism | EXIF ColorSpace field or an ICC profile in APP2 |
| PNG mechanisms | sRGB, gAMA, cHRM, iCCP or cICP chunks |
| Untagged default | Most software assumes sRGB |
| Symptom of a wrong tag | Flat and grey, or oversaturated |
Slide the table sideways to see every column.
Where does the tag live in each format?
Every format has its own slot for it.
- JPEG. The EXIF
ColorSpacefield, where 1 means sRGB and 65535 means uncalibrated, or a complete ICC profile carried in an APP2 segment. - PNG. An
sRGBchunk naming the standard space,gAMAandcHRMchunks describing the curve and primaries, aniCCPchunk holding an embedded profile, or thecICPchunk added in the Third Edition, which also covers HDR signalling. - WebP and AVIF. A dedicated profile chunk or colour box, holding either an ICC profile or a compact set of standard code points.
What actually goes wrong when the tag is missing?
Software has to guess, and it guesses sRGB. If the file really is sRGB, nothing happens and you never notice. If it came from a camera set to Adobe RGB, the saturated colours render short of where they should be and the image looks flat and slightly grey.
The opposite error produces the opposite result. An sRGB file wrongly marked as a wide space, or displayed by software that ignores colour management on a wide-gamut screen, comes out oversaturated, with reds pushing towards orange and skin looking sunburnt.
What people get wrong about colour tag
Each one is a real failure mode, not a style preference.
Changing the tag to fix colours that look wrong, which shifts every pixel's meaning instead of correcting the values.
Enabling strip-all-metadata in a batch job to save bytes, which removes the colour tag along with the EXIF and copyright fields.
Testing colour on one uncalibrated monitor in a viewer that ignores tags entirely, where tagged and untagged files look identical.
Questions people ask
Colour tag, answered
The follow-up questions people search for once they have the definition.
How do I check whether an image is tagged?
Open it in an editor and look at the document or file info panel, which names the colour space, or use an operating system file inspector that lists colour data. Metadata tools that read EXIF and ICC data will also report it. Nothing listed means untagged.
Is an untagged image a problem for marketplace listings?
Only if it is not sRGB. Platforms and browsers assume sRGB for untagged files, so an untagged sRGB image renders correctly. Convert wide-gamut files to sRGB before upload and the tag becomes a safety net rather than a requirement.
Does a colour tag make my file bigger?
A named tag such as a PNG sRGB chunk or an EXIF field is a handful of bytes. A full embedded sRGB profile is a few kilobytes. Both are trivial compared to the image data, so stripping them is rarely worth the risk.
Same cluster
More from the glossary
Neighbouring entries, so every term in the set is one hop from every other.
Compression artefact
A compression artefact is visible damage introduced by lossy encoding: blocky squares, halos around hard edges, muddy colour at boundaries, or stepped gradients.
Compression ratio
Compression ratio is the size of the original image divided by the size of the compressed file, written as something like 10:1.
Contrast
Contrast is the tonal separation between the light and dark parts of an image.
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Sources
Where the facts on this page come from. Every link opens the specification, standard or documentation the claim was read at.
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