What is LAB Color Space?
When it comes to digital editing, there are several different types of color spaces (or color modes). A color space, in its most basic sense, is similar to a recipe: it is a computer's way of combining a small amount of colors into a very, very wide range of colors.
- For example, RGB (red, green, blue) produces all of the colors we see on our computer monitors and TVs through various combinations of red, blue and green.
- Another example is CMYK (cyan, magenta, yellow, black) which is a color space used for printing, combining those four colors in ink to create the colors in a print.
- Then there is also LAB Color Space, which stands for Lightness, A channel, B channel (hence, "LAB").
In much the same way that a RAW file is sort of a non-entity and needs to be converted to a file that we can see (such as a .TIFF or .DNG), LAB color is also more of a theory, because LAB color space represents such a wide range of color, that many of them cannot be seen by the human eye, either on our monitors or printed in ink.
In short, LAB color offers more precision and control in certain areas than editing in RGB. There are many ways you can work with LAB to enhance your workflow, so let's look at something that we all love extra help with: COLOR!
Converting Your Image to LAB Color Space
In Photoshop, you can easily switch from RGB to LAB Color. Just click on select Edit>Convert to Profile:
Under Destination Space, select Lab Color:
Create a Curves Adjustment Layer
We are going to be looking at LAB Color Space through the Curves channels, so you will need to create a new Photoshop Curves Layer:
When you open the drop down menu in your Curves panel, where you would normally see the RGB channels, you'll now see Lightness, A & B, as I mentioned above. Here is what each channel represents:
- Lightness - affects the overall luminance of the image, light or dark, with no relationship to color.
- A-channel - shows information on greens and magentas.
- B-channel - shows information on yellows and blues.
Photoshop LAB Color Adjustments
As with any sort of fine-tuning in Photoshop, there is no set formula for how much you should adjust each channel, as the amounts will not only vary from image to image, but the amounts will also depend on your personal taste.
I like to err on the side of caution and build up as I go, so I have made a subtle shift here. As you can see below, I have pulled both of my triangular sliders in, towards the outlying points on the histogram. I have found that an input of -90 to -100 on the left slider and 90 to 100 on the right is a good starting point.
You can see on the model's face where her skin is already getting a nice, warm tone to it. I have the image divided in half so you can see the difference in the before/after:
Move the sliders in the B channel exactly the same way. The goal here is to get a nice balance between green, magenta, blue and yellow:
For the Lightness channel, I once again brought my sliders in, towards my histogram, and then I pulled up from the center of the histogram towards the highlights (upper left). This brightened the image in much the same way a curves adjustment would in RGB, but the effect is much more subtle and has less contrast:
As you can see above, the adjustments made in LAB are extremely subtle, but give the image much more definition.
Once you have made your adjustments in LAB, you will need to switch back to Adobe RGB (1998)* in order to do your normal editing. In LAB, you will not be able to make adjustments such as Exposure, Vibrance and Selective Color.
*Side note: convert to Adobe RGB (1998) after you edit in LAB. sRGB is the standard default color space and does not offer the same range as Adobe RGB.
Why Edit in LAB Color Space?
Think of using LAB editing as part of you workflow in much the same way as shooting in RAW vs. JPEG - it gives you the chance to make more fine-tuned edits, so that not only will the image look better on you monitor, it will look exponentially better when printed!
And when it comes to editing, if something gives you MORE CONTROL, you should probably take advantage of it!
Do you have any questions or comments about editing in LAB Color Space? Leave us a comment below - we would LOVE to hear from you! And please share this tutorial using the social sharing buttons (we really appreciate it)!