Great work. Have you tried water resistant mdf? you can get a good crisp finish and a depth of about 4mm because it has been treated. Also I strongly recommend you use limewood,( really sort but close grained so you can go very fine). Holly is very hard and close grained and good for miniature pieces. And if you can get it english walnut for crisp work. It will make all the difference and wont blunt your chisels like mdf. Thanks for sharing.
RE: Art & Woodworking: How I relief carved Space Whales. Complete process with pictures.