Reads:

"Example: If the draw:blue attribute has the value 50% and and the blue color channel has 8 bits, then 128 is added to the blue color value of each pixel inside the image before it is rendered. If draw:blue has the value -50% then 128 is subtracted.

The draw:blue attribute specifies the offset for the blue color channel. "

It is hard to distinguish the last sentence as being part of the example from the normal text.

Moreover, the entire example should be a note.

Suggest:

"For example, if the..."

And treat the entire two paragraphs as one note but separate paragraphs.