Using colour space and colour model interchangeably, when RGB is the model and sRGB is one specific space built on it.
Colour
Colour space
Also called color space, colourspace or working space. 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 space is a defined mapping from numbers to actual colours. It specifies the exact primaries, the white point and the transfer function, so that a value such as 200,40,40 names one specific red. Without a colour space, RGB numbers are instructions with no units attached.
Updated
The short version
Colour space at a glance
| Quick fact | Detail |
|---|---|
| Defines | Primaries, white point, transfer function |
| Web default | sRGB |
| Common wide spaces | Display P3, Adobe RGB, Rec. 2020 |
| Editing master space | A wide space at 16 bits per channel |
| Attached to files by | An embedded profile or a colour tag |
Slide the table sideways to see every column.
What has to be defined before numbers mean colours?
Three ingredients, and all three are needed.
- Primaries. The precise red, green and blue the space is built from, given as coordinates on a chromaticity diagram. These set the corners of what the space can reach.
- White point. What counts as neutral white, usually D65 for screen spaces and D50 for print work.
- Transfer function. How stored values relate to light intensity. sRGB uses a piecewise curve that approximates gamma 2.2; HDR spaces use PQ or HLG instead.
Change any one of these and the same triple of numbers becomes a different colour.
How do the common spaces compare?
| Space | Reach | Where you meet it |
|---|---|---|
| sRGB | The baseline everything else is measured against | Web, marketplace listings, most consumer screens |
| Display P3 | Wider than sRGB, mainly in reds and greens | Recent phones, tablets and laptop displays |
| Adobe RGB (1998) | Wider than sRGB, mainly in cyans and greens | Print-oriented photography workflows |
| ProPhoto RGB | Very wide, extending beyond visible colours | 16-bit editing masters, never for delivery |
| Rec. 2020 | Much wider again | HDR and UHD video, no consumer display covers it fully |
Display P3 is worth a note: it borrows the DCI-P3 primaries but pairs them with a D65 white point and an sRGB-style transfer curve, which is why files convert between it and sRGB so cleanly.
What is the difference between a working space and a device space?
A working space is the neutral, device-independent space you edit in. It is symmetrical and well behaved, so tools such as curves and blur do predictable things. sRGB, Adobe RGB and ProPhoto RGB are all working spaces.
A device space describes what one physical thing can do: this monitor, this printer with this paper and ink. Device spaces are lumpy and irregular. Colour management works by translating from your working space into a device space at the moment of display or printing, which is what monitor calibration and printer profiles are for.
Why does the same file look different in two apps?
Usually because one application is colour managed and the other is not. A colour-managed application reads the file's profile, works out what the numbers mean and converts them for your display. A non-managed one throws the numbers straight at the screen.
On an sRGB monitor with an sRGB file, both routes look identical, which is why the problem stays hidden for years. Put a wide-gamut display or a Display P3 file into the mix and the two paths diverge immediately, with the non-managed one oversaturating.
What people get wrong about colour space
Each one is a real failure mode, not a style preference.
Editing in ProPhoto RGB at 8 bits, where the space is wide enough that the gaps between adjacent values show as banding.
Expecting a wide-gamut export to look richer online, when browsers and platforms that ignore the profile render it duller instead.
Judging colour on an uncalibrated wide-gamut monitor in a non-managed viewer, where every sRGB image looks more saturated than it is.
Questions people ask
Colour space, answered
The follow-up questions people search for once they have the definition.
Which colour space should I use for online listings?
sRGB. It is what browsers and marketplace image pipelines assume when a file carries no profile, so it is the one space that cannot be misread. Keep a wider master if you edit heavily, and export an sRGB copy for upload.
Is a colour space the same as a colour profile?
No. The colour space is the definition; the profile is the data that carries or references that definition and attaches it to a file or a device. One sRGB space, many sRGB profiles produced by different vendors, all describing the same thing.
Can converting between colour spaces damage an image?
Converting from wide to narrow permanently discards colours that fall outside the target. Repeated round trips at 8 bits per channel also accumulate rounding errors that show as banding. Convert once, late in the process, from a 16-bit master.
What is a device-independent colour space?
One defined by human vision measurements rather than by any particular hardware, such as CIEXYZ or CIELAB. Colour management uses these as the common reference that every conversion passes through, so a monitor profile and a printer profile can be related to each other.
Same cluster
More from the glossary
Neighbouring entries, so every term in the set is one hop from every other.
Colour tag
A colour tag is the small piece of metadata in an image file that declares which colour space its pixel values belong to.
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.
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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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