Colour spaces and monitor calibration: sRGB, P3 and Delta E

In short: A colour space defines which colours can be displayed; sRGB is the standard for the web, wide-gamut monitors show more, and calibration ensures correct colours.

In more detail: Two monitors often show the same file differently: one glows bluish, the other warm, one shows stronger reds and greens. This is down to colour space and calibration.

In Depth

Colour spaces

• sRGB: standard for web, games, office. Almost all images and monitors are designed for it.
• Adobe RGB: larger, especially in green and cyan, for print and photography.
• DCI-P3 (Display P3): larger in red/green, cinema and modern smartphones/laptops.
• Rec. 2020: very large, for HDR video. The coverage (“99 % sRGB”, “95 % DCI-P3”) shows how much of a colour space the monitor can display. Colour depth: 8 bit (16.7 million colours) or 10 bit (over 1 billion, fewer bands in gradients).

Key figures

• Delta E (ΔE): colour deviation from target; under 2 is considered barely visible, under 1 very accurate.
• White point: 6500 K (D65) is common.
• Gamma: 2.2 (sRGB).
• Brightness: for office about 100 to 150 cd/m² (cd/m² = nit), for HDR much more.
• Contrast, panel type (IPS good for colours, OLED very high contrast).

Calibration

With a colorimeter (for example Datacolor Spyder, Calibrite) and software you measure the display and create an ICC profile that the operating system takes into account. Important for photo, video and graphics work and printing. For everyday use these suffice: factory setting to “sRGB mode”, adjust brightness, use night mode with care. Colour management in programs (Photoshop, browser) must be active, otherwise images look paler or too garish.

Practical tips

A wide-gamut monitor without colour management shows sRGB content oversaturated; choose sRGB emulation in the settings. Export images for the web as sRGB. Before buying look at panel, coverage, ΔE values and test reports; manufacturer data is optimistic. Gaming monitors focus on Hz and response time, not colour accuracy.

See also: Panel types, HDR and brightness, WCAG and colour contrast