Making your photos pop using Lab Color

[evil4blue]

After seeing the other thread about color pop, I figured I'd share this little technique. I'm too lazy to write this up the correct way, so I'll explain the process and attach a bunch of screenies to help demonstrate the technique.

First things first, why do this in Lab color and not just boost the saturation. Simple answer, because boosting RGB saturation also effects the luminosity (poor man's exposure) of your photo. Lab color boost only effects the colors and not the shades of gray in your photo. Lab color boosting also has a lesser effect on noise and artifacts and tends to result in a more natural color boost.

Here's how it's done:

1. open image
2. convert to Lab color
3. add a curves adjustment layer
4. change the channel drop down to 'a' channel
5. click on the curve point at the bottom left corner and drag it to the right (and only to the right, not up) about 10 points.
6. click on the curve point at the top right corner and drag it to the left (and only to the left, not down) about 10 points. You can move these points more or less than 10, but they both must be an equal amount.
7. change the channel drop down to 'b' channel
8. repeat steps 5 and 6
9. hit OK
10. toggle on and off the layer to see the difference
11. convert back to RGB
12. when asked, select 'flatten'.
13. save

There you go, you just did your very first Lab color correction. The following images show the process outlined above and the last 2 images are a before and after of a photo I used this process on.

[jeffkohn]

Here's an action I use to make the process easier. It uses fairly conservative LAB curves, but since the action uses and Adjustment layer you can tweak to your heart's content. The action layer also sets the layer's blend properties such that the curve doesn't effect parts of the image that are already strongly saturated (otherwise if you apply these types of adjustments to an image that has bold colors in it already, they tend to go "nuclear" and look unreal).

There's also an action that makes converting back to RGB a one-step operation, although if your working space isn't the same as mine you may want to edit this one.

BTW I'm using Photoshop CS2, I have no idea if this action file will load into previous versions of Photoshop.

[jeffkohn]

damn, just remember the action references a saved curve file, so here's another zip. To use the action "as-is" the curve file would need to go in C:\Multimedia\Photoshop Actions; otherwise you'll have to edit the action by double-clicking the appropriate line in the action and loading the curve file from the correct path.

[Redmouse]

Thanks for the tip and the actions.

[evil4blue]

Thanks Jeff for uploading those actions. I also have a number of actions that do some of the basics in th lab color, but figured that showing a very basic curve adjustment would go a little further in teaching the technique then just saying, "hey download this, it works".

[Shane]

thanks for the tip - just used it with a couple of photos and wow - the colors POP!!!

[Jake]

Thanks Stevil and Jeff for taking the time to post this. I just tried it and it looks pretty good. I have not done the action yet. All I've ever done in LAB was sharpened and a few other things but I did not really know what I was doing.

[LoungeLizard]

I'll have to try it...thanks to both of you.

Now, stupid question time (remember, relative PS newbie here). Now that I know the steps, can you explain what and why it happens/works this way? (For extra credit, of course!)

[DAPhoto]

Great PS tips here! You guys are great for sharing that!

[evil4blue]

Originally Posted by LoungeLizard

I'll have to try it...thanks to both of you.

Now, stupid question time (remember, relative PS newbie here). Now that I know the steps, can you explain what and why it happens/works this way? (For extra credit, of course!)

This is much too complex a subject to fully discuss, but I'll to give you a little background.

Lab color is the only color space available in PS that lets you separate the color from the luminosity. Lab consists of basically 6 colors: black, white, red, green, blue, and yellow. Each channel in the curves dialog represents the relationship of a pair of the above colors. L = black and white, a = red and green, and b = blue and yellow. When you adjust a curve in any of these channels, your actually changing the relationship of one color to another. By adjusting the curve in the manner I did in that basic example you are just steepening the curve around the center point of the graph and thus intensifying the colors. The steeper the curve the more intense the color. As long as the center point doesn't stray from its original placement, you won't see any color casts develop in the middle tones.

Now you have to be careful using Lab to adjust colors because the lab color space is huge, much bigger than even prophoto. There is a possibility of out-of-gamut colors being generated. You can also create imaginary colors, like a black-yellow or a white-red, but that's for a different discussion.

One of Jeff's actions helps avoid out-of-gamut colors by not allowing the adjusted curve to be applied on colors that are already super saturated. Lab is a pretty powerful editing space, but should be used with some respect. You can really honk things up if your not careful.

Like Jake had mentioned above, you can also sharpen in Lab (which I believe is the best way to do so). If you convert to Lab and then apply your sharpening to only the L channel, you'll avoid color halos.

Lab is also great for noise reduction. If you have a lot of color noise, you and run a slight Gaussian blur on the a and b channels to remove a good portion of the noise found in your high ISO shots.

There are a lot of other neat thing that you can do, but these few techniques should keep y'all busy. I'd suggest getting a book on the Lab color space for anyone that would like to learn more.

[LoungeLizard]

Steve, thanks for taking the time. I've got a basic understanding of LAB color, but your explanation now helps me understaind why this works!

[Mike G]

Defintely improves the colors in my images .. thanks!