[Gimp-user] Indexed PNGs

[William Trenker]

Hello,

Having followed the many good tutorials I'm starting to get somewhere with the GIMP (1.2.3 - Windows98).  Now I'm trying to reduced the file-size of the final images by indexing them before saving as PNG's.  But when I try indexing the image, most of the anti-aliasing and other  "fuzziness" pixels are gone.   Here's a simple example:

File/New (RGB, background)

Layers/New (transparent)

Tool - Fuzzy Brush

Brush Selection - Circle Fuzzy (19)

Colors - Foreground: Red, Background:White

With transparent layer selected draw anything (a squiggly line)

Tool - Smudge

Smudge the squiggly line

Now index the image (with the Transparent layer still selected):

Image/Mode/Index  (defaults: Optimal Palette=255)

And I've lost almost all the fuzziness.  The indexed palette shows only 53 shades of red and 1 shade of white.  Most of the pixels that make the really fine fuzziness, that make the smudging look good, are gone.

Ok, now undo the Indexing, Merge Down the layers and do the Indexing again.

Fine,  this time the image hasn't lost the finer shades of red (ie the subtle smudging is still there and the fuzzy line is still fuzzy).  The Indexed Palette has 255 values ranging from full-red to full-white.

BUT I have a white background.  I don't want a white background I want a transparent background.

So, I undo the Merge Down, delete the background layer, and try Indexing again.

Rats!  The smudging and fuzziness are gone again.  The Indexed Palette is back to only 53 shades of red.

So what am I doing wrong?  (I've tried playing with the transparency button on the layers dialog, I've tried the Dither Transparency option on the Index dialog.)  What do I do to get a single layer in one color to give me an Indexed Palette with 255 "shades" of transparency?

Thanks for being patient.

Bill Trenker
Kelowna BC Canada

"The commandments of the LORD are right, bringing joy to the heart. The commands of the LORD are clear, giving insight to life . . . For this is the love of God, that we keep His commandments. And His commandments are not burdensome." (Psalm 19:8, 1John 5:3)    torahteacher.com

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