Convert works with 600dpi but fails with 1200dpi?

[joew]

Hello everybody,

I am trying to add a background to a postscript text (generated with latex). My first attempt was:

Code: Select all

convert \
    -density 600 \
    -size 1935x1062 \
    plasma:yellow-limegreen \
    -fill black \
    -gravity center \( labels4.ps -trim +repage \) \
    -composite \
    -rotate -90 \
    output-600.png

This works fine and gives me a yellow-limegreen plasma background for the whole picture. So the postscript text seems to be transparent. Then I tried to do the same, but with 1200 DPI:

Code: Select all

MAGIC_TMPDIR=/var/tmp convert \
    -density 1200 \
    -size 3870x2124 \
    plasma:yellow-limegreen \
    -fill black \
    -gravity center \( labels4.ps -trim +repage \) \
    -composite \
    -rotate -90 \
    output-1200.png

But here, I get the yellow-limegreen background only on the area that is not covered by the postscript text. It looks like the postscript is no longer transparent, and I get text on white background surrounded by yellow-limegreen plasma.

Any ideas what's going wrong here?