Posterize and then easy way separate into layers?

[waters_tc]

OK, I can easily take my image and posterize it to a number of colors- let's say, 4 colors.  But once that is done, is there an easy way to select each of of the four colors and seperate them onto seperate layers?  I've used the magic want to select, and then choose similar, but I often get more than just the one color I want. so there must be an easier way.

THX

[kevin stohlmeyer]

Have you tried using Select Color Range? That will allow you to preview your selection and add/remove from it with sliders and tools.

[waters_tc]

No, thx, I totally missed that that option existed.  I'll play with it.  This would allow me to manually select by color and then copy/paste to seperate layers, but it seems like there ought to be a way for photoshop to do that on its own.

[c.pfaffenbichler]

»This would allow me to manually select by color and then copy/paste to seperate layers«

Copy/pasting seems wateful, Layer > New > Layer Via Copy (cmd-J). 

»but it seems like there ought to be a way for photoshop to do that on its own.«

Why? 

When you used the Magic Wand did you uncheck Anti-aliasing and Contiguous? 

The task could be automated via a Script, but it hardly seems worth the trouble if it’s not a very frequent task? 

Are the four colors always the same ones? If so an Action might suffice. 

[waters_tc]

No, I hadn't unselected anything in the Magic Wand.  Can you explain what unchecking these settings does?  How do these settings affect what gets selected?  I did change the tolerance.  Really apopreciate learning more about how these settings work.

[c.pfaffenbichler]

Anti-aliasing results in softened edges for Selections. 

And the contiguous setting affects whether the tool selects pixels of the same color that are not directly connected to the clicked pixel by similar pixels. 

[Lumigraphics]

You can use Spot Colors and those would be on their own channels, or Indexed Color Mode which is similar.

[JJMack]

Once you get the four colors make sure you only you have four colors by converting to Index color 4 colors. You can the convert back to RGB mode.  You should then bet able to select each of the four colors with the magic wand tool.