09-26-2019, 12:11 AM
[attachment=3198 Wrote:rich2005 pid='14888' dateline='1569397750'][attachment=3198][attachment=3198]
Quote:...I'd like to isolate some colors in a photo.
It is to hopefully reveal a hidden message. I'm thinking I can remove some colors (maybe convert them to a specific color like white) so what's left are all colors except what I picked.
Is the 'photo' an indexed image? Typically a gif or a png maybe a bmp, top of the Gimp window will tell you. If it is it is worth trying;
Colors -> Map -> Set Color map
Choose an limited palette, Used volcano here. screenshot https://i.imgur.com/XvcxwBL.jpg
With a bit of luck any 'hidden text' will show. https://i.imgur.com/G5g1jlR.jpg
Originally, all to do with editing an indexed image colormap. Look for a suspicious entry in the colormap. https://i.imgur.com/sZ3KFgd.jpg Assign a new color. https://i.imgur.com/YJ2virv.jpg
On the other hand, If a jpg, tif or other RGB image then the number of colors (apart from grayscale) will be in the thousands and probably some other method than changed colours used to hide the text. Sometimes fast-fourier-transform (FFT) is used.
Hello Rich,
Thanks for the answer. It's a JPEG taken with my digital camera. And it has a lot of different colors in it.
I guess i could select all pixels of a certain color, but then I'd need to select many times to remove all the different shades of a certain color.
Would there be a 'color range selector' tool?
Here's a snippet of the image. How can i isolate or only show the darkest shades of the groove?
The rest of the stone can be white.