As you can see on the image, the OptiFine cape background is completly black. That's because I removed a color byte to the banner, so it appears black.
And because this is possible, is also possible making certain layers completly black? I would like to have a cape like following, but every byte I modified just didn't work.
Template for new cape
Banner on this link. I would like to not have the gray background, but the part of the wall like on the link white on pure black background. https://livzmc.net/banner/?=paaeafaEasay&valign=m This is what I want to achieve: