Re: Display "Saturation" Effect

Posted by karo03 on Oct 09, 2009; 8:01pm
URL: http://imagej.273.s1.nabble.com/Display-Saturation-Effect-tp3690879p3690880.html

gif images are indexed images. The pixel value is translated via a  
lookup table. You should change the image->type to 8-bit or RGB and  
use than Image->Adjust->Brightness/Contrast for changes.
Regards
Karsten

Am 09.10.2009 um 21:06 schrieb David William Webster:

> All,
>
> I am having a funny problem(?) with some 8-bit imagery whereby bright
> pixels get rolled over and displayed as near black or dark. This  
> seems to
> happen when I add a value to the pixels to shift their dynamic  
> range. For
> example, with the TTTREES2.gif image on the website included below,  
> if I
> add 100 to each pixel (using Process/Math/Add ...) in an image to  
> bring
> the dynamic range from say 0-133 to 100-233, large sections of higher
> values show up as dark, not bright. This doesn't seem to happen with  
> other
> images. Can someone tell me what's up?
>
> David Webster
> http://www.siggraph.org/s95/S95_V1/COMUNITY/OSIRIS/OSIRIS.HTL
> You can save this page as html and get the gifs in a folder.

Karsten
[hidden email]