Switch colours painlessly
James Paterson shows how to grips with this useful Photoshop mode and learn how to take complete control of colour in your workflow
Make accurate colour swaps with Photoshop CC’S LAB mode
LAB Color mode might sound like something that requires a white coat and a clipboard, but it isn’t just for digital imaging boffins, it’s for anyone who wants to shift, boost and take control of the colour in their photos. In this tutorial, we’ll explain how it works.
First, a little about colour modes. Most of the time we view and work on images in the RGB colour mode. This stands for Red, Green and Blue, and from combinations of these three colours any other colour can be made. When in RGB mode each pixel has a specific R, G and B value between 0 and 255. This determines not just the colour intensity but also the brightness of the pixel. For example, if a pixel has R 255, G 255, B 255 then it is fully white. So in RGB mode the colour and brightness of any given pixel are bound, making it difficult to change one independently of the other.
LAB Color works differently. When we switch to LAB each pixel is again designated three values, just like RGB. But instead of three colour values, there are two – the A and B channels. The third channel – L – is dedicated to luminance. Put them all together and we get L-A-B.
Unlike RGB the LAB values are based on how the eye sees colour, not how a device calculates it, and it brings some important benefits. It means we can alter colours independently of brightness, like with the car here. We can also boost colour saturation and convert to monochrome. Here’s how…
The LAB values are based on how the eye sees colour, not how a device calculates it, and it brings some important benefits