Minecraft TP question?

Helo,

I'm currently working on a TexturePack because of the free time which I want to combine with the Cape by Basti. Now I can't get the inventory to be easily seen. Reducing the opacity did nothing.

What do I have to do?

I don't know exactly in which format the Minecraft files are saved, but this usually works with the opacity reduction for .png files

I do this at Gimp, reduce it to 50% and in the game there's color, but still the same opacity