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What Is Colour Space? (sRGB, Adobe RGB, ProPhoto RGB)
Every digital image uses numbers to describe its colours. A pixel might be defined as (200, 50, 30), meaning a certain amount of red, green, and blue. But those numbers are meaningless on their own. Without a shared definition of what "200 red" looks like, every screen, printer, and piece of software would interpret the same numbers differently.
A colour space is that shared definition. It is a specific, standardised range of colours that gives meaning to the numerical values in an image file. Think of it as a vocabulary of colours: the colour space defines which colours are speakable, and the numbers in the file pick specific words from that vocabulary. A larger colour space has a richer vocabulary; it can describe more colours, including subtler variations and more vivid tones. A smaller one is more limited but more widely understood.
This matters for anyone who works with images, whether you are a photographer editing in Lightroom, a designer preparing files for print, or someone who has ever exported a photo and wondered why it looked flat and lifeless on the web.
Why colour spaces exist
The core problem is that different devices can reproduce different ranges of colour. A high-end wide-gamut monitor can display vivid greens and deep reds that a standard office monitor cannot. A professional inkjet printer can produce colours that no monitor can display, and vice versa. Your phone screen, your laptop, your desktop monitor, and the printer at the photo lab all have different capabilities.
Without colour spaces, there would be no way to ensure consistency. An image that looks vivid on one screen might look muted on another, not because of a settings difference, but because the two devices are interpreting the same colour numbers in fundamentally different ways.
Colour spaces solve this by providing a fixed reference. When an image is tagged with a colour space (say, sRGB), any colour-managed application knows precisely what each colour value means. If the display cannot reproduce a particular colour, the software can at least make a sensible substitution. Without the tag, the application has to guess, and guesses are often wrong.
The main colour spaces explained
Four colour spaces come up repeatedly in photography, design, and digital publishing. Each occupies a different position on the spectrum from "widely compatible" to "technically expansive."
sRGB
sRGB (standard Red Green Blue) is the default colour space of the web, and of most consumer displays. It was defined in 1996 by HP and Microsoft to standardise colour across monitors and the internet, and it remains the baseline that nearly everything targets.
The gamut of sRGB, the range of colours it can represent, is relatively narrow compared to other colour spaces. It covers roughly 35 per cent of the visible spectrum. This sounds limiting, but it matches what most screens can display. If you are publishing images to a website, sharing photos on social media, or preparing visuals for a standard monitor, sRGB is the correct choice. It is the common language that virtually every device and browser understands.
The limitation of sRGB is that it clips vivid colours. Deep cyans, saturated greens, and certain rich oranges that exist in the real world fall outside the sRGB gamut. If you are working with images that contain these colours, editing in sRGB means losing information from the start.
Adobe RGB
Adobe RGB was created by Adobe in 1998 to address the gap between what sRGB could describe and what CMYK printers could reproduce. Its gamut is roughly 50 per cent of the visible spectrum, notably wider than sRGB, particularly in the greens and cyans.
Adobe RGB is the standard working space for professional print photography and graphic design. If your images will be printed, whether on a professional inkjet, in a magazine, or as fine art, Adobe RGB preserves colour information that sRGB would discard. Many professional cameras offer the option to capture in Adobe RGB rather than sRGB, and most professional editing software supports it natively.
The caveat is that Adobe RGB images need colour-managed viewing to look correct. On a standard sRGB monitor, or in a browser that does not handle colour management properly, an Adobe RGB image can look noticeably dull. This is the source of the "washed-out export" problem, which we will return to shortly.
ProPhoto RGB
ProPhoto RGB is the widest commonly used colour space, covering roughly 90 per cent of the visible spectrum. It can describe colours so vivid that no current display technology can reproduce them and, in some cases, colours that the human eye cannot perceive.
This might sound impractical, but ProPhoto RGB serves an important purpose in high-end editing workflows. When you edit a RAW photograph, the sensor data from the camera often contains colour information that exceeds both sRGB and Adobe RGB. Editing in ProPhoto RGB preserves this data throughout the editing process, giving you the maximum flexibility to make adjustments without clipping colours prematurely. The conversion to a smaller gamut happens only at export, when you know the destination.
ProPhoto RGB requires 16-bit colour depth to avoid visible banding (the appearance of harsh steps between similar tones). Working in 8-bit ProPhoto RGB can introduce artefacts because the gamut is spread so wide that 256 levels per channel are not enough to represent smooth gradations. If your editing software supports 16-bit workflows, ProPhoto RGB is a strong choice for your working space. If it does not, Adobe RGB is a safer option.
Display P3
Display P3 is Apple's wide-gamut colour space, adopted across iPhones, iPads, and Mac displays since around 2016. It covers about 25 per cent more of the visible spectrum than sRGB, extending particularly into reds and greens. It has become increasingly relevant as wide-gamut displays have moved from professional studios into everyday devices.
Display P3 occupies an interesting middle ground. It is wider than sRGB, so photos and videos can look more vivid on P3 displays. But it is narrower than Adobe RGB, so it does not introduce the same compatibility challenges for web publishing. Modern web browsers on Apple devices handle P3 content natively, and CSS now supports P3 colour values. If you are creating content primarily for screens (rather than print), Display P3 is an increasingly practical choice, though sRGB remains the safer default when you do not know what display your audience is using.
When colour space matters
Colour space is not something you need to think about constantly, but there are specific moments in a workflow where choosing the wrong one causes visible problems.
During editing, working in a wider colour space preserves more data and gives you more room for adjustments. Pushing exposure, adjusting saturation, or recovering shadows in a wider space is less likely to produce banding or colour clipping than doing the same work in sRGB. This is why professional editing software defaults to wide-gamut working spaces. Understanding image file formats helps here, because some formats support wide gamuts better than others.
During export for the web, sRGB is the correct target. Browsers, social media platforms, and most web-based viewers assume sRGB unless told otherwise. Exporting in a wider colour space without proper tagging produces the characteristic washed-out look that confuses many photographers.
During export for print, a wider space preserves colours that the printer can reproduce but sRGB cannot. Adobe RGB is the standard for most print workflows. Your print lab or prepress provider will usually specify their requirements, and soft-proofing in your editing software lets you preview how colours will translate before you commit to paper.
For video, the relevant colour spaces are Rec. 709 (the standard for HD video, roughly equivalent to sRGB in gamut) and Rec. 2020 (the standard for HDR and 4K content, significantly wider). If you work with video alongside stills, understanding these parallels helps maintain consistency across formats.
The washed-out export problem
This is the single most common colour space issue, and it catches people regularly. The symptom is simple: a photo looks vibrant and punchy in your editing software, but when you export it and view it on the web or share it, the colours look flat, desaturated, and lifeless.
The cause is a mismatch between the colour space embedded in the exported file and the colour space the viewer assumes. If you edit in Adobe RGB or ProPhoto RGB and export a JPEG without converting to sRGB, the file carries those wider-gamut colour values. When a browser or application that expects sRGB encounters these values, it interprets them as sRGB numbers. Because Adobe RGB's colour values are distributed differently, the same numbers that represent vivid colours in Adobe RGB represent muted colours when misread as sRGB.
The fix is to convert to sRGB on export when the destination is the web or screen viewing. Every major editing application offers this option. In Lightroom, it is in the export dialogue under "Color Space." In Photoshop, "Edit > Convert to Profile" or the "Save for Web" function handles it. In Capture One, the export recipe includes a colour space selector. The conversion remaps the colour values so that the colours look the same in the smaller gamut, or as close as the smaller gamut permits.
It is worth noting that this problem only occurs when the exported file is not properly tagged or when the viewing application ignores the embedded colour profile. Modern colour-managed applications (including current versions of Chrome, Safari, and Firefox) will read an embedded Adobe RGB profile and display the image correctly. But not all viewers are colour-managed, and social media platforms often strip profiles during their own processing. Converting to sRGB on export remains the safest approach for anything destined for the web.
How to check and convert colour space
Knowing your current colour space and how to convert between spaces is a core skill for anyone working with images.
In Adobe Lightroom, the working space for editing is fixed (Lightroom uses its own wide-gamut space internally). Colour space comes into play at export: the Export dialogue includes a "Color Space" dropdown where you select sRGB, Adobe RGB, or ProPhoto RGB. For web use, choose sRGB. For print, choose Adobe RGB or ask your printer.
In Adobe Photoshop, the current colour space is shown in the document's title bar (look for "sRGB," "Adobe RGB," or similar after the file name). To convert, use Edit > Convert to Profile and select the target space. Use "Convert to Profile" rather than "Assign Profile" as conversion remaps the colour values to look the same, while assigning simply reinterprets existing values (which changes how they look).
In Capture One, the working colour space is set per session or catalogue, and the output colour space is part of the export (process) recipe. Set the output to sRGB for web deliverables and Adobe RGB for print.
If you are working with files in a general-purpose workspace or cloud storage system, be aware that uploading and downloading images should not change their colour profile, but some services re-encode images in ways that may strip or alter metadata. Check that your colour profile survives the round trip, particularly for professional photography files.
Colour management in operating systems
The operating system plays a role in how colours appear on your screen, because it sits between your software and your display.
macOS has robust colour management built in. It reads the ICC profile of your display (a file that describes the monitor's colour characteristics) and adjusts output accordingly. Applications that are colour-managed, including Safari, Preview, and all Adobe software, work through this system to display colours accurately. macOS also supports wide-gamut displays natively, so Display P3 content looks correct on compatible hardware.
Windows colour management has improved over the years but has historically been less consistent. Windows supports ICC profiles and colour-managed applications, but not all software uses the system's colour management. Some browsers and image viewers on Windows have displayed untagged or non-sRGB images incorrectly, though modern versions of Edge and Chrome handle this well. If colour accuracy matters to your work on Windows, verify that your browser and image viewer are colour-managed.
Monitor calibration is a separate but related concern. Even with correct colour management, if your monitor does not accurately reproduce the colours it is told to display, what you see will not match what others see. Hardware calibration devices (colorimeters) measure your monitor's output and generate a custom ICC profile that compensates for its characteristics. For professional work in photography and design, calibration is essential. For casual use, the factory profile on a decent monitor is usually adequate.
Practical recommendations
The following guidelines cover most situations without requiring deep technical knowledge.
Capture in the widest space your camera supports. If your camera offers an Adobe RGB setting, use it. If you shoot RAW (and you should for anything you intend to edit seriously), the colour space setting in camera mainly affects the embedded JPEG preview; the RAW data itself contains the full sensor information regardless of the setting. Understanding RAW vs JPEG vs HEIF helps clarify this.
Edit in a wide-gamut space. Let your editing software work in its native wide-gamut space (ProPhoto RGB or the application's own internal space). This preserves maximum colour data during editing. Do not convert to sRGB before editing, as you would be throwing away data before you start.
Convert on export, based on the destination. For the web, social media, email, and screen viewing: sRGB. For print: Adobe RGB, or whatever your printer specifies. For archival purposes: the widest space you have, ideally alongside a sRGB version for quick viewing.
Embed the colour profile in every export. Most editing software does this by default, but verify it. An image without an embedded profile is ambiguous, and viewers will guess (usually assuming sRGB, which is correct for sRGB files but wrong for anything wider).
Preserve metadata when moving files between systems. Colour profile information is part of the file's metadata. Workflows that strip metadata can strip the colour profile, leading to the same misinterpretation problems as an untagged file.
Keep your originals. A workspace that supports visual search and smart organisation makes it practical to keep both wide-gamut originals and sRGB exports without losing track of which is which.
Frequently asked questions
What colour space should I use for Instagram and social media?
sRGB. Social media platforms process and re-encode uploaded images, and their pipelines assume sRGB. Uploading in a wider colour space may result in colour shifts or a washed-out appearance. Convert to sRGB before uploading for the most predictable results.
Does colour space affect file size?
Not directly. The colour space defines the interpretation of colour values, not the amount of data stored. However, working in a wider colour space often goes hand in hand with higher bit depth (16-bit instead of 8-bit), which does increase file size. An 8-bit sRGB JPEG and an 8-bit Adobe RGB JPEG of the same image will be roughly the same size.
Can I convert from sRGB to Adobe RGB to get more colour?
No. Converting from a smaller colour space to a larger one does not add colour information that was not there before. The colours already clipped to sRGB boundaries remain clipped. Conversion to a wider space only helps if the source data (such as a RAW file) contains wider-gamut information. Converting a finished sRGB JPEG to Adobe RGB changes the numbers but not the actual colours.
What is the difference between "assign" and "convert" profile?
Assigning a profile reinterprets the existing colour numbers under a new definition. The numbers stay the same, but their meaning changes, so the image looks different. Converting a profile remaps the numbers so that the colours look the same (or as close as possible) under the new definition. In nearly all cases, you want "convert," not "assign." Assign is useful only when a file has been incorrectly tagged and you know its true colour space.
Do phone cameras shoot in sRGB?
Most Android phones shoot in sRGB by default. iPhones since the iPhone 7 capture in Display P3 when using the default camera app, which is a wider gamut than sRGB. For most uses this is handled transparently by iOS, but if you transfer photos to non-Apple devices or upload to services that do not handle P3, you may see slight colour shifts.
What happens if I ignore colour space entirely?
For casual use, very little. If you take photos on your phone, share them on social media, and view them on standard screens, the default sRGB pipeline handles everything transparently. Colour space becomes important when you edit photos and want the edited version to look the same on different devices, when you prepare images for print, or when you work in a professional context where colour accuracy affects the quality of the output. If you have ever wondered why an exported photo looks different from what you saw while editing, colour space is almost certainly the reason.