You can force QTR to put glop in 255 white areas by doing the following:

– Open appropriate xyz.quad file in a plain text editor (like Notepad or TextEdit)
– Look for line that starts with “# Y curve” or whatever position glop is in. It will look something like this:
# Y curve
0
32347
31927
31506
31086

The 0 means in 255 spot it will not put down glop. Change 0 to something else, in sequence with numbers under it. Doesn’t have to be precise, just duplicating the number below it will be fine.

If you do this it will put glop on the entire page, including areas outside your actual image. You could keep two versions of your .quad file, one with and the other without this hack.

Here is a simple proof: print a pure white image. If the printhead starts to move left-right like it is printing something, it is placing glop. If it just spits the page right out of the printer, you have no glop on pure white.