THere are multiple choices.
1. India ink hand written on a stick on label.
2. identification written using a scratchall on the glass slide
3. computer-generated printed labels stick on.
You also have the option of placing labels under a coverslip, but you
must use ink/lead that wil not be miscible
Hello:
Undergraduates working with me and I are about to begin generating several
thousand "permanent" glass microscope slides containing
micro-invertebrates. I would like to know what have you found is the best
combination of label (ideally never to be removed from the slide) and print
material t