Notes*

sRGB, Adobe RGB or DCI‑P3?

Colour management feels a bit of a black art sometimes, and one that can easily cause a workflow meltdown. You can arrive at a point where it all makes sense, then a reasonable question brings the wall tumbling down! It’s an area where many variables can alter a colour-managed workflow, including ourselves.

The three primary colour spaces that we are perhaps most familiar with are sRGB, Adobe RGB and DCI-P3. What are the key differences? As can be seen below, it’s basically the range of colour able to be captured/displayed. How this actually appears to us is grounded in our perception of colour and dependent upon the devices we are using.

Our individual perception, colour blindness, environmental conditions and proximity of colours to each other can all impact how we perceive colour as well as the technical limitations of our hardware. Both sRGB and Rec. 709 cover similar colour spaces, but appear different to each other due to having different gamma settings; luminance curves.

The redrawn CIE 1931 chromaticity diagram below, with chromaticity coordinate values (x, y) of the D65 illuminant (average sunlight), shows the most important RGB colour gamuts in graphic and cartographic workflows. As a reference, the commonly used European standard CMYK profile, FOGRA39¹ (ISO 12647-2:2004) is shown as are the video profiles Rec. 709 and Rec. 2020 and one for the photographers, ProPhoto RGB. It is a visual representation only and not a mathematically generated graph, the intention to simply compare the RGB colour gamuts against each other within the wider visible spectrum.

The CIE 1931 chromaticity diagram with chromaticity coordinate values (x, y) of the D65 illuminant (average sunlight)

sRGB

This is the baseline and default for most digital activities. Most monitors these days can achieve (almost) 100% sRGB so we can be reasonably confident that what we see on screen is what everyone else will also see in a colour-managed workflow. It is a capture space option in digital photography. It covers much of typical CMYK spectrums, so for all intents and purposes, works well for most graphic and cartographic workflows. It's quite predictable and your workflow will be consistent if this is your benchmark. This is the profile to keep to if you want a more simplified workflow and colour consistency across devices. Ideal for displaying work online.

Adobe RGB

Also seen as an option on digital cameras, it’s also bundled with Adobe’s profesional publishing tools; InDesign, Illustrator and Photoshop. It was designed to bridge the gap between RGB and CMYK, so has more of a print focus. A more complicated workflow, for sure, but it does have its value in print and high end photography, especially if you use Pantone colours, whose range extends well beyond sRGB. It captures all CMYK print intents so increases confidence in print workflow. Its greater gamut does require a monitor capable of showing it otherwise it’s quite pointless attempting to apply it in a workflow.

Many find that imagery looks less saturated than sRGB, which can be off-putting to some, but that is due to the ‘pull’ of 8-bit imagery over a wider gamut, avoiding the compression in some areas due to the rendering intent; perceptual tends to be used for imagery and colormetric on graphics. It can also be down to incorrect settings in a colour-managed workflow. The prevalence of over-saturated images is designed to appeal to consumers rather than professionals. It requires an extra step of conversion to sRGB if the output is to be used online, but that is not really much of an issue and means you have a workflow that is more flexible and attuned to all output possibilities.

DCI-P3

The new kid on the block. As can be seen, it is nearly as wide a gamut as Adobe RGB and ‘tipped’ to superceed sRGB in due course. Apple uses this a default ganut for its screens, which is no surprise as it developed the variant Display P3. Originally, the colour space was developed for motion picture, so ideal for video producers. However, is now recognised as being a good space for print as it also covers a substantial amount of the CMYK gamut. Moreover, this gamut is more easily achievad by monitor manufacturers than Adobe RGB.

In summary

All three profiles have benefits and fit professional workflows, just be aware of the content you are creating and applying workflows consistently throughout. Also ensure your devices are correctly calibrated and profiled as there’s no point working with Adobe RGB if your monitor can barely cover the sRGB colour space! Personally, I work from the Adobe RGB color space having a monitor that achieves that space 100%. That works for me, so take your time to find what works for you with your set up.


¹ Now technically superceeded by FOGRA51 (PSO Coated v3 / ISO 12647-2:2013) in Europe. Visit the European Color Initiative and FOGRA for more information and profiles.