I exported some 32-bit tiffs (with transparency) from Ultra that I had keyed and brought them into Illustrator and to do a batch process using Live Trace. But when I opened the images in Illustrator (CS3), they no longer had any transparencey (the previoulsy transparent areas were now grayish versions of the green screen that I had initially removed in Ultra). I found the same to be true in Photoshop CS3. But when I brought the images into After Effects CS3, they looked fine (the transparent areas were still transparent). Does this have something to do with how Illustrator and PS handle alpha channels? How can I do what I want to do in Illustrator? (Ultimately, I want to bring these image sequences into AE for compositing, but would like to modify them using live trace in Illustrator first)
In Illustrator I've dealt with a similar issue importing Targa files, the transparent area becomes a light green tint.
After doing a color Live Trace I had to Object/Expand, than select one of these green-tint areas with the Direct or Group Select tool, than Select/Same: Fill Color, than delete.
I'm unsure how or if you can add the "Object/Expand, Select/Same: Fill Color, delete" operation into a batch process, but this might help.
If you do devise a batch process that addresses this, I'm sure we'd all love to hear about it.