Photoshop CS4 has added a new Vibrance command. You can find it on the Image | Adjustments submenu. There is also a new Vibrance adjustment layer. (Definitely my preference, since you can work non-destructively with the command this way.)

Some users confuse Vibrance and Saturation. That's understandable, since Vibrance and Saturation are related. Vibrance is a "tamer" version of the Saturation command. You're less likely to cause serious damage to your photograph with the Vibrance command because it has more "smarts" than the Saturation command.

I'm going to use a test target from Bruce Lindbloom to demonstrate the difference for the effects from the Vibrance and Saturation commands. His site is among the best on the Web for learning about colorspaces. The test target is useful here because it has a range of colors, some highly saturated and some not.

Vibrance increases the saturation for an image, but unlike the Saturation command, it includes two important protections:

• Skin tones are protected. This prevents skin tones from taking on a red or yellow cast.
• Highly saturated colors are protected against clipping. This avoids unwanted color shifts and loss of important detail.

You will also find that the Vibrance command makes smaller adjustments to image saturation than does the Saturation command. I'll demonstate that by using the same setting for both.

You can use any image you like to confirm the difference between the Vibrance and Saturation commands. Start by making a Vibrance adjustment layer.

You can adjust Vibrance or Saturation from the same panel. I started by setting Vibrance to +80. Below are the "before" and "after" screenshots for Bruce Lindblom's test target.

I pushed the slider to +80. Nearly to maximum (+100). The colors have more "pop" after the Vibrance adjustment. (I'm working hard not to say they have more vibrance.) The difference is not an "in your face" kind of effect. Equally important, the flesh colored patch in the upper left corner of the simulated Macbeth Color Checker Card has been protected and the Blue, Green, Red, and Yellow patches have not been clipped.

The Yellow patch went from 85 to 93% saturation. It was most in danger of clipping. The Red patch went from 74 to 84%, the Green from 54 to 71%, and the Blue from 70 to 83%. The flesh colored patch went from 34 to 41% saturation but its hue was almost completely unchanged, going from 18 to 19 degrees.

Now, before and after for a +80 adjustment to Saturation . . .

Ouch! There are some really big color shifts going on. That comes from clipping highly saturated colors. Some like the Magenta and Cyan patches have taken on a fluorescent appearance.

Look at the patch immediately above the Red patch. It went from 57 to 100% saturation and the hue shifted around the color circle from 354 to 347 degrees. In terms of CMYK, Magenta for the same patch goes from 82 to 100%.

I used the Info Panel to look at the saturation for the different patches. As I moved the mouse cursor, the before/after results for the Vibrance adjustment layer were displayed. The example above is the Red patch with +80 for the Saturation slider.

The flesh colored patch has also begun to shift color. Saturation went from 34 to 59%. The hue also shifted.

Below are the comparisons between Vibrance (top) and Saturation (bottom) slider settings.

Clearly, the results for Vibrance and Saturation are not at all identical. When you need a more sweeping change to the colors in a photo, the Saturation command will do the job. When you need to protect skin tones or you want to boost the saturation of colors in a more controlled way, think first about Vibrance.

You can download a .PDF version of this "tip" from this URL:

http://www.thelightsright.com/files/tips/VibranceVersusSaturation/VibranceVersusSaturation.pdf

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