Hi,

Conrad Newton writes:

I have been trying to create an image with , my red-and-black image consists of 100 or more colors. I thought there were only two colors (does black even count as a color?), but clearly I was naive.

It would help if you would explain how you created that image. Perhaps you can put it online so we can have a look.

Sven

Hi there!

On Friday 19 December 2003 13:47, Conrad Newton wrote:

I have been trying to create an image with , my red-and-black image consists of 100 or more colors. I thought there were only two colors (does black even count as a color?), but clearly I was naive.

Can someone give me a hint?? I am (obviously) a GIMP newbie.

So, the matter here is that printed colors are represented differently for printing and for screen rendering.

When you talk about two colors here, you are obviously thinking on the number of physical inks you'd need to print out your image. (which actually would be three in a home printer, but f you want more details on that, I will write on another e-mail, lest this one become huge).

Colors as displayed on the screen, however, are counted differently. Each shade of the "same" color counts as a different color. Thus a less intense red, is a different color than a more intense red. A Red with some black mixed, is neither red nor black, but encoded as different color.

Actually, for displaying colors on the Screen, the GIMP uses more than 16 million "different" colors. Which are printed on inkjet printers using normally four physical inks. The printing process simulates the multitude of colors by "half toning" i.e. printing sparse dot's of each different ink.

Now, on the pratical side, if someone asked you to send a 16 color image, and you are trying to achieve that in the GIMP, go to the menu "image","mode", "indexed", set the desired number of colors there, and let The GIMP do its stuff. You may go back with undo, an d retry with different options when indexing the image to achieve better results.

If you have any further doubts, just write in.

Regards, JS
->

Thanks, Conrad

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Hi Conrad,

Conrad Newton wrote:

According to a "colorcube analysis", my red-and-black image consists of 100 or more colors. I thought there were only two colors (does black even count as a color?), but clearly I was naive.

The borders between the red & black areas are probably antialiased, giving several colors in between for a smooth transition. You might see this if you zoom in on an edge.

Can someone give me a hint?? I am (obviously) a GIMP newbie.

The indexed image type is exactly for this. You can convert your image to indexed, and specify an optimal palette of 16 colours; this will construct a palette to represent your image as well as possible with the 16 colours. If you decide later that you really want more, then comvert your image back to RGB, add the extra stuff, and re-convert to indexed.

A piece of advice: while some people actually work in indexed mode, it is more usual, and easier on the sanity, to work in RGB, and only convert to indexed as a final stage before saving the image.

Cheers,
Dave.