Lots of black around MIRAX slides

[ajwood at mta.ca]

Hi,

I'm noticing that when I read MIRAX slides, there is a lot of black around the
valuable part of the image. This black doesn't show up when I convert the
slides with a Windows proprietary conversion software, but it does when I read
the slides with OpenSlide.

Is the proprietary software simply smart enough to crop away the black, or am I
maybe reading the slide incorrectly?

Thanks,

Andrew