I also used guache instead of tempera and paper instead of parchment, because I didn't have any tempera and parchment at the time.
It is a little bit off topic really, but here are some pics of the few illuminations I did (already some years ago). They are copies of illutriations of 'Der naturen bloeme' of Jacob van Maerlant.
The reason I did them quite a lot bigger than the original ones (they can be seen here), is that at the time I didn't know the originals were smaller. During the painting I figured out they must have been smaller because, in fact, it's more difficult to do them big. The originals are a lot 'rougher' than my version. Actually I did them way too neat.
I made them just as try-outs, to get used to the style and find the right colours. I'm not completely satisfied with them, but over-all they look quite pretty.
I made a copy of this one on parchment, but still with guache. It was a birthdaypresent for my boyfriend two years ago. It also is the last illumination I did. In the mean time I have tempera, but I haven't tried it yet.
In the end I maybe might go as far to mix my own pigments, or maybe not :-) We'll see where it takes me.