Ran across this one while surfing tonight.

http://www.adobe.com/tips/phs8posteriz/main.html

I wrote an action (attached) based on the concept that piles on a few adjustment layers for ultimate tweaking flexibilty. Kind of a fun toy if you need something new to play with.

Image courtesy of www.Innographics.com.

Have fun.

~Danny~

I've used this technique and a modification of it at least twice on posts I've made to this forum. It is fun and easy.

I'm going to add my two cents worth and hope someone takes the add ons to this tutorial and runs with them.

1. I've found that using posterize often gives jaggies (for lack of a better word) that result in a blotchy effect. Using median and a slight gaussian blur to blend will often correct that.

or

2. Make at least three copies of the background. On the first, use Threshold with the slider positioned to create a darker image. Lower opacity to your liking. Second layer, use Threshold in the middle (default). Lower opacity. On the third, use Threshold for a lighter selection. Keep opacity at 100 percent as this is the bottom layer and most likely you don't want the original showing through.

Using Threshold eliminates the problem of the jaggies and gives a nice, smooth transition between shadowing. Play around with your settings as each picture is slightly different. I'm sure you will find something that works.

Now you can merge the three layers (or four depending in your taste) and apply a gradient map.

3. Sometimes with flowers and such, I will also solarize and invert after using the Threshold and gradient map. This gives a funky spin to a piece of art work. I've even played around with using solarize and invert on regular flowers and then trying out the impressionist and other Photoshop filters.

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Janet: Excellent contribution!
~Danny~

The eye opener for me was the observation that applying Posterize, levels = 4 to a color image results in 4 levels per channel = 12 tones. By desaturating the image, each channel is identical, so if you specify Posterize levels =4, you get 4 tones.

Ding! :)

~Danny~