Count all unique colors in image

[revnart]

Hey, do you have any idea how to count unique colors in image? some kind of script, plugin or idea?
Yes, I know I can use indexed color for images that have less than 256 colors, but I need to know if my image has more or less unique colors.
My base file uses all of 16,777,216 possible color, and after different transformations I need to calculate the loss of color.

I've found one plugin from:
link: http://www.users.cloud9.net/~gparet/photoshop/#counter
but it doesn't run on my machine.

Any ideas? Thanks for help

EDIT:
Just found one that is working, in case someone need here is the link:
http://telegraphics.com.au/sw/product/CountColours

 

[polarwoc]

That looks and sounds good, but what is the utility practically?

 

[revnart]

In "design" utility of this is hmm.. small but I needed to know how big is loss of colors after certain things you do in photoshop.

As a somehow useful information for people editing photographs in LAB mode: sRGB has much smaller gamut than LAB but when you convert image to LAB mode you throw away a lot of colors. If you convert it back to RGB you again throw away color data so you have much much less colors than in original

Of course during design of business cards etc. It's not so "important" but in photography probably a little but again I needed this not for my daily routine but for "research"

 

[IngridO]

Another good way to count colors is use "Faststone Image Viewer" it is free!
On LHS menu just click COUNT.

It give all colors counted.

 

[revnart]

Thanks, good to know I have backup solution

 

[IngridO]

You are very welcome! I use Faststone every day for quick edits. It is very powerful program.