How colour management uses profiles
Each profile describes a device or a colour space in relation to a device-independent reference, the Profile Connection Space (CIE XYZ or CIELAB). To convert an image from one profile to another, the colour management software maps its values from the source profile to that reference, then from the reference to the destination profile.
| Profile class | Describes | Example |
|---|---|---|
| Input | A scanner or camera | A scanner profile built from a target |
| Display | A monitor | A calibrated laptop screen |
| Output | A printer or press, usually CMYK | Coated offset paper |
| Colour space | A standard working space | sRGB, Adobe RGB |
When the destination cannot show some colours of the source, a rendering intent decides what happens. ICC profiles define four: perceptual, relative colorimetric, saturation and absolute colorimetric. Perceptual compresses the whole range to keep relationships between colours; relative colorimetric keeps in-range colours exact and moves the rest to the nearest printable colour.
Common colour profiles
| Profile | Gamut | Typical use |
|---|---|---|
| sRGB (IEC 61966-2-1:1999) | Smallest of the common RGB spaces | Web, email, office documents, most screens |
| Display P3 | Wider than sRGB, especially reds and greens | Recent phones, laptops and monitors |
| Adobe RGB (1998) | Wider than sRGB in greens and cyans | Professional photography, print preparation |
| ProPhoto RGB | Very wide | Editing raw photographs |
| CMYK print profiles, for example based on FOGRA39 | Limited by inks and paper | Offset printing on coated paper |
| Greyscale | Black to white only | Black-and-white print |
What goes wrong without colour management
- No profile. Software assumes sRGB. That is correct for most web images and wrong for a file saved in another space without its profile.
- Profile ignored. An Adobe RGB photo shown by software that ignores profiles looks dull and desaturated.
- Profile stripped without conversion. A resizing tool that removes the profile but keeps the numbers makes the same mistake, and the dull colours are now part of the new file.
- CMYK on screen. A CMYK JPEG meant for print is larger than an RGB one, and some web software displays it with wrong colours.
- Round trips. Converting a wide-gamut image to CMYK and back cannot restore the colours lost on the way.
A typical B2B case: an agency delivers catalogue packshots in Adobe RGB, the web team resizes them with a tool that strips the profile, and the brand red on the website no longer matches the printed catalogue. Or a distributor receives a CMYK TIFF prepared for the press and places it on its website.
Colour profiles in a DAM workflow
- Keep the original exactly as delivered, with its embedded profile, as the master file.
- Produce web renditions in sRGB by converting through the embedded profile, never by discarding it.
- Give print users the original, or a rendition made for their press profile.
- Specify brand colours separately for each medium: HEX or RGB for screens, CMYK or a spot colour reference for print.
ICC profiles in Freedam
- The original file is kept as uploaded, with its embedded profile. Original Quality in the download dialog delivers that file unchanged.
- Previews and resized downloads of images with an Adobe RGB, ProPhoto or CMYK profile are converted to sRGB through the embedded profile, so their colours stay close to the original. Images without a profile are converted according to their colour space.
- Display P3 images keep their Display P3 profile in previews and resized downloads, because browsers and recent devices show the wider gamut.
- A watermarked file is always an sRGB JPEG. The image is converted through its embedded profile before the watermark is added.
- Resized files keep the copyright, creator, credit line, usage terms and web statement of the original. Other metadata, such as GPS position and camera details, is left out.
- Templates imported from PSD files render in sRGB, so a CMYK or wide-gamut PSD shifts slightly towards sRGB.
- Palettes in the brand guide show HEX, RGB, CMYK and Pantone (PMS) values. CMYK values are calculated automatically and can be overridden.
Details: the download dialog in the Freedam docs, and the TIFF and PSD format pages.
Frequently asked questions
What is the difference between a colour profile and a colour space?
A colour space is a defined range of colours with a way of numbering them, such as sRGB or Adobe RGB. A colour profile is the file that describes a colour space or a device precisely enough for software to convert between them. An image tagged with the sRGB profile is declaring that its numbers are sRGB values.
Should images for the web be sRGB?
Yes, as a rule. sRGB displays consistently in browsers, email clients and office software. Display P3 is shown correctly by current browsers on wide-gamut screens, but sRGB remains the safe choice for files sent to partners whose software you do not know.
Why do my images look dull after export or upload?
Usually because an Adobe RGB or ProPhoto image was shown or resized without its profile being applied. Convert the image to sRGB through its profile rather than assigning sRGB, or use a system that converts renditions through the embedded profile.
Related terms
Compare an original with its web copy
Upload an Adobe RGB or CMYK image to Nordi's demo library, then download it as the original and at a smaller size: the smaller copy is converted to sRGB through its embedded profile.
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