|
One of my favorite not-so-secret Photoshop tricks uses Lab Color to allow you to make both dramatic and subtle changes in color saturation. I think of it as making an adjustment in a different color dimension than normal RGB saturation changes. Wiki has a decent discussion of Lab Color. When using this manipulation, be cautious not to introduce banding or posterization artifacts.
Photoshop is Like Makeup The best thing is to look natural, but it takes makeup to look natural. Calvin Klein Kiss and make up--but too much makeup has ruined many a kiss. Mae West Summary of Steps - Flatten image (if needed)
- Convert to Lab Color
- Manipulate color using the levels dialo
- Manipulate the A channel
- Manipulate the B channel
- Tone-down the wild-color effect
- Flatten the image
- Convert back to RGB color
- Save your file
1) Flatten the Image  Photoshop doesn't allow you to maintain standard layers or adjustment layers when you convert to a different color mode. So if you use layers extensively, you need to plan your work accordingly. Either do your Lab Color work at the beginning of your workflow or at the end. I prefer the beginning because I conduct output sharpening at the end of my workflow. 2) Convert to Lab Color  On the menu-bar, select the Image>Mode>Lab Color option. At this stage, you are taking your color and remapping it to a new color space. You shouldn't be able to see any changes at this point. 3) Manipulate Color Using the Levels Dialog  Most people have toyed with Levels. Not everyone realizes that levels can be focused on specific color channels. In RGB mode this means that you can apply levels to only one of the channels—red/cyan, green/magenta, blue/yellow—as well as the combined RGB channel where luminance is adjusted. In Lab color, you can adjust three channels—luminance, A, and B. The A channel represents green/magenta. The B channel represents blue/yellow. 
4) Manipulate the A Channel
Use the Levels Adjustment Layer and start with the A channel and drag the left and right sliders towards the central portion of the histogram where the data resides. Right now, the image will look bad. Drag the center slider back and forth until you can find something that is roughly pure white—do your best to balance the color between the green and magenta. Your image will still look bad.  5) Manipulate the B Channel
Now move on to the B channel and repeat the levels adjustment while trying to balance the blue and yellow channels. At this point you might love the effect or you might hate it, but the color will be dramatic. Don't worry, we aren't done yet.  6) Tone-Down the Wild-Color Effect Select the Levels adjustment layer in the layers panel. Click on the opacity box and drag the slider from 100% to 0%. You will notice the effect will be absent at 0% and will be strong at 100%. Move the slider back-and-forth until your image has a pleasing appearance. I frequently find somewhere between 50% and 65% works well, but every image will be different so you will want to experiment for yourself to find what you like. If you want, you can also paint-in a mask to selectively hide the effect.  7) Flatten the ImageIf you forget to flatten your image, Photshop will prompt you to flatten before converting to RGB color in the next step. 8) Convert Back to RGB Color Lab color will not work if you want to print your image or display it on the web, so you want to convert back to RGB color. These conversions are destructive, so don't go back and forth. On the menu bar, select the Image>Mode>RGB option to convert back into the RGB color mode. 
9) Save Your File 
| 