What are Colour-Spaces?

[ricktas]

What is a a colour-space?

Scientifically it is a abstract mathematical model describing the way colors can be represented. What this means is that any particular colour-space has a limited number of colours it can contain. So photographically we often hear about the sRGB colour-space. What this actually is, is a formula for displaying and representing all the colours that the sRGB colour-space is able to use.

Not all colour-spaces are equal, some contain the ability to display/use more colours than others.

Here is a small chart representing some of the more commonly used colour-spaces
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Illustration courtesy Jeff Schewe
from A Color Managed Workflow (http://www.adobe.com/digitalimag/pdfs/color_managed_raw_workflow.pdf)
which is found on the Adobe Web site.

As can be seen in the graphic above, some colour-spaces contain a larger range of colours than others. This can be important as far as we photographers are concerned cause we work everyday with colours. When you compare the sRGB colour-space to the ProPhoto colour-space, you can see how many colours are being 'clipped' when you photograph or process using sRGB.

I hope this small post gives you an early insight into colour-spaces and how they can affect the results you see when you take photos.

[Rattus79]

This explains alot about colour clipping in graduations when you reduce the size of an image for web.
Thanks Rick, I never really gave this much thought before.

[GJC]

Thanks Rick,
On my Canon's I have the option of Adobe RGB, or sRGB. When taking Raw images, does the colour Space still make a difference, or is it only if you're getting the camera to produce JPEG's?

[ricktas]

Thanks Rick,
On my Canon's I have the option of Adobe RGB, or sRGB. When taking Raw images, does the colour Space still make a difference, or is it only if you're getting the camera to produce JPEG's?

RAW files do not have a defined colourspace. So you can set it to whatever colourspace you want, in your editing software. Where this does come in, is if you convert RAW to TIF and use sRGB, then save that file, you lose the benefits that AdobeRGB and Pro-Photo have etc.

HOWEVER. Most printers and monitors cannot print/display the full AdobeRGB gamut, let alone the Pro Photo one. So using them now, probably seems like overkill, but in the future, as technology improves, and we can view photos in the full AdobeRGB or ProPhoto gamut, then any photo you have already saved as sRGB is going to be lacking.

Note that AdobeRGB monitors and printers are available and coming down in price, but even two years ago you would pay several thousand dollars for a 98% AdobeRGB monitor

[GJC]

Thanks Rick