convert produces pdf with red background?

[erinspice]

Forgive me if this is a known issue or frequent question. I did a google search and only found results pertaining to printing pdfs with red backgrounds, and a search of this forum yielded no results.

I'm using "convert" to crop pdfs from legal size to A4 with this command:

convert -crop 612x770 input.pdf output.pdf

When viewed in evince, my input pdf looks just fine, but my output.pdf, while cropped correctly, has a bright red background. How can I get rid of this?

[anthony]

It would probably help to at least add a +0+0 to the crop, or you will be doing a tile crop!