Artifacts in Quark?

[SleepJunkie]

I'm playing around with Alpha channels in Quark. I created files in Photoshop and I saved htem as tifs. I just noticed that when I place those images on anything but a solid color, I get an artifact of a box. I can't figure out why it is doing this. I'm very new to Quark, just started on it for an ad that I'm doing for work. I have supplied a screenshot of the exported PDF.

Help is greatly appreciated, especially if it is quick!

http://img412.imageshack.us/img412/6924/screenshot4hp7.png

[SleepJunkie]

After clipping them they work perfectly. I'd still like to know why it wasn't working as a plain alpha channel. I planned on this taking 2 hours to figure out. Ten minutes isn't so bad!

But anyway, still looking for information as to why this may have happened.

Edit: I probably don't understand how drop shadows work yet. I had all of my images working fine, after clipping them. Once I added a drop shadow, the artifacts came back. The drop shadows aren't important now, but these boxes are bugging me :)