Forum archive

PNG colors

blah at 2005-11-30 01:15
Some time ago, I created a grayscale PNG for use on a web page. I originally experimented with different color depths and different settings of PNGOUT to make sure that the file was as small as possible.

However, I've noticed recently that the white background of the said image does not exactly match the white background of the web page. I have no idea whether this is due to palette values, some gamma nonsense or something else altogether.

Is there an easy way to edit the palette and remove any gamma information to make the background completely white while preserving the compressed image data? I'd like to avoid having to redo the optimization work from scratch. The image in question can be found at this URL.
Awesoken at 2005-11-30 02:40
It looks like the white in your image is only 253,253,253. You'll have to use an image editor to fix that and compress again. Here are good PNGOUT settings for your image:
```
pngout seikkailupeli-listaus.png /c3 /d2 /b0
```
blah at 2005-11-30 03:19
Worked great
Ken, thanks a lot! I fixed the palette and applied the PNGOUT settings you suggested. The file is now down to 68683 bytes from 78624.

By the way, I'm on OS X so thanks for the Mac port of PNGOUT, too.