Understanding color spaces

I'll try to explain it very simplified, but understandable for everyone.

Think for a color space as a circle. As there can exist different sized circles, so there can exist different color spaces, that can envelop a different volume of color descriptions or color numbers. The bigger the circle, the wider the gamut of the color space. For example, the Lab color space is wider than any RGB color space. The CMYK gamut is tighter than any RGB color gamut. All these are different color models – Lab is an internal color mode, used by the graphic applications; RGB is an output color mode for computer peripherals; and CMYK is a color model for describing colors, used by the offset printing process.

In this short tip I will try to determine the better of two RGB color spaces – AdobeRGB and sRGB.

AdobeRGB and sRGB color spaces.

AdobeRGB is a large gamut color space developed by Adobe Inc. especially for their graphic design applications and, first of all, for Photoshop.

This color space was introduced under the name SMPTE-240M, but with Photoshop 5.0.2 it was renamed to AdobeRGB(1998).

sRGB is the standard color space, developed to set a standard in many computer output peripherals – monitors, low-end printers and scanners an some other. Many devices use this color space as default since it is standard. All digital cameras have this space as a default.

Which one is better for you – AdobeRGB or sRGB

The main difference between both color spaces is that AdobeRGB has a larger gamut than sRGB.

AdobeRGB is a professional color space, suitable for most graphic design and photo editing applications. It is better for professional work where the richness of colors is essential. It matches better the colors within the CMYK color model, so if you work for CMYK output, the colors with the AdobeRGB color space will match better the CMYK colors when your work is outputted. Note that this RGB color space is NOT the largest one. There are out there ProPhotoRGB and some others that have wider gamut than AdobeRGB.

It's the same with digital cameras. If you shoot for professional graphic design projects, the better color space for you is AdobeRGB. I will grab more colors than the standard sRGB. AdobeRGB is supported by some of the top-quality DSLR cameras from Canon, Nikon and some other.

Here comes a problem: if you shoot AdobeRGB and you open your photos in a standard sRGB image-view application (like IrfanView, ACDSee, Internet explorer etc.), you will not see a correct color. Your photos will look desaturated and low in contrast. Even if you have an image application that supports color management, you'll probably still see desaturated colors. This is caused by the fact many cameras (I shoot with Canon and know it from my experience) do not embed the color profile in the photo.

The best way to see and use the colors AdobeRGB produces is to open the file in Photoshop and apply the shooting color space – in this case – AdobeRGB.

I strongly recommend you to shoot RAW files instead of JPGs. RAW files are better in any aspect – they are not lossy-compressed, and they can be processed using different color spaces and different settings for white balance, exposure compensation, brightness, contrast and other. The original file stays, so you can process it again and again with different spaces. In the Photoshop RAW processing module you can even correct lens' chromatic aberrations. The bad news here: low-end cameras have not support for RAW files, so if you want to use this great file format, you'll got to pay some more bucks and get a high quality camera.

Processing RAW files you can use larger color spaces for your resulting file – for example the Kodak's ProPhotoRGB. More on this – in a future article dedicated of the famous RAW format and the advantages of the ProPhotoRGB color space.

sRGB is the right choice for graphic projects and photos prepared for the Internet or that will be printed on low-end inc-jet or color laser printers. This is also the color space for sheared graphic projects and photos as this standard profile reduces color mismatching problems. Use this space if you send files in a lab for processing and printing. There are some labs that will handle files with no matter what color profile (Do not forget to embed the profile!), but to be sure there will not be color representation problems, just send files with sRGB profile included.

Admonitions

A wider color space is not always better. The choice depends on your needs. For most amateur photographers and a big part of the pros sRGB will be OK. Photos in sRGB require much less post-processing and color adjustments.

To make an all-purpose photo archive and have the advantages of every color space, supported by your image application, just shoot RAW. A RAW file contains a big amount of data that is clipped by the in-camera image processing software an is lost forever. Shooting RAW you can profit from wide color space like AdobeRGB and ProPhotoRGB, unavailable with the JPG files, processed in the camera.