An introduction to Lab Color mode

Lab Color Mode (LAB) is an alternative colorspace that enables you to manipulate the luminosity and colour of your images more flexibly and powerfully than when working within RGB. In this, my first LAB tutorial, I hope to achieve three things. First, I will provide a brief explanation of the theory and numbers behind LAB (and how to work with these within Photoshop). Second, I will demonstrate the advantages of LAB over RGB – i.e. its ability to dramatically alter colour – both in terms of tone and saturation – more flexibly and with less degradation to your images than when using RGB. Third, using a range of real world examples, I will show you how to use LAB to:

• Dramatically alter the contrast of an image without affecting its colour balance or saturation.
• Increase the saturation of an image with less image noise and cleaner colour separation than when working in RGB.
• Alter the tone and colour balance of your images by adjusting the ‘a’ and ‘b’ channels within LAB.
• Invert specific colours and colour ranges using the Curves tool within LAB.

This tutorial contains 6566 words, 68 illustrative images and screen grabs, and has received 40 comments.

Photoshop files included with this tutorial

Each of our tutorials is based around a series of Photoshop files, at the resolution originally posted on chromasia, and each contains all the original adjustment layers I used to create the final image. The ones that are included in this tutorial, and a brief description of how each one will be used, are listed below – the ‘before’ version on the left, the ‘after’ version on the right. Each of these files can be downloaded after you subscribe.

How to get from this …	to this
			Image 1 In this example I will show you how to use LAB to dramatically increase i) the contrast of an image (using the Lightness channel), and ii) its saturation (by manipulating the ‘a’ and ‘b’ channels).
			Image 2 In this example I show you how to alter the ‘a’ and ‘b’ channels within LAB colour mode to add a unique tone to your images.
			Image 3 In this example I will show you how to use the ‘a’ and ‘b’ Curves to i) partially desaturate an image, and ii) alter its colour balance.
			Image 4 In this example I will show you how to manipulate the ‘a’ and ‘b’ Curves to invert a specific colour range within an image.

What our subscribers have said about this tutorial

"This is a very good tutorial. When compared to Dan Margulis' work on LAB, which is complex and lacks examples, this tutorial stands out on it's own due to it's assisting photoshop users in expanding their creative wings." Jason Hope		"I find this tutorial, and anything related to LAB to be very important. I too have the Dan Margulis book and several online tutorials on LAB, but this was by far the easiest to understand, and the most applicable to photographers. Thanx!"