Hi, Microinspecter
You can make a permanent slide by starting with a well slide, and making an acetate gasket cut the size of the cover slip with the inside cut out.
stick this down with Canada Balsam or clear nail polish. Then put the specimen in the air space and fill with mounting medium, then seal with a cover slip.
You can also mount them dry with this method. Works pretty good with ants, but spiders and flies tend to spoil over time, unless you prep them.
For temporary slides just for photography, you can build up a dam of petroleum jelly around the edge of the cover slip and put the specimen in the airspace.
Top lighting is essential for photographing and indeed seeing a 3 dimensional specimen. A high intensity desk lamp works good for this.
I have an LED point source attached to a goose neck that I use.
Here is a crab spider dry mounted in this manner. It is still fresh when this shot was taken. This one is in dark field illumination with top lighting.
![forum02_edof.jpg](./download/file.php?id=7156&sid=e1f09685e5ef7f229ce10322908b35d4)
- forum02_edof.jpg (248.13 KiB) Viewed 7949 times
Here is another shot of the same mount taken with just top lighting. You can see the deterioration over just a couple of weeks.
![forum03.jpg](./download/file.php?id=7157&sid=e1f09685e5ef7f229ce10322908b35d4)
- forum03.jpg (131.37 KiB) Viewed 7949 times
This one is a pavement ant I just sat on a slide without a cover slip and used a blue filter in the condenser tray dimmed down and top lighting for detail.
![forum01.jpg](./download/file.php?id=7158&sid=e1f09685e5ef7f229ce10322908b35d4)
- forum01.jpg (221.19 KiB) Viewed 7949 times
So you can indeed use 3 dimensional specimens but the lighting is what will make your images pop.