I thought I'd try my hand with colour slide film, and I'm quite interested in processing it myself too.

I'm at a very early stage in getting to grips with exposure though (first two rolls just came back from the lab, mostly seriously overexposed!) so while I'm a complete novice there are two sets of variables to consider - exposure and processing.

Is there any way (from looking at a slide) of determining whether any image problems are due to exposure error or processing incompetence? With black and white I can pretty much tell whether the exposure is out or whether the developing is out - how would I tell the difference in E6?

This is what you need:
Kodak: Visual Troubleshooting of Process E6. (http://www.kodak.com/global/plugins/acrobat/en/service/Zmanuals/z119-12.pdf)

Actually, the Kodak E6 documentation is excellent and one of my very few permanent bookmarks - the rest of the docs are here (http://www.kodak.com/global/en/business/retailPhoto/techInfo/zManuals/z119.jhtml).

Thanks Tim, lots of really useful information there.

With negative film we expose for the shadow detail. With transparency film we expose for the highlights.

The basic rule of thumb for starting your exposure calculation of the scene.

yes, that was my mistake this time round. I metered with the emphasis on the darker parts of the scene instead of the lighter parts. Anything with plenty of sky in it was blown completely, but scenes in more subdued light came out a little dark in my opinion. Next time I'll give the brighter parts more emphasis in metering and give a bit more exposure in the shady shots.

Still, it seems to be easier for me to interpret my exposure errors properly with a direct positive than it is with a B&W negative.