.
Repeating here to facilitate locating it. viewtopic.php?f=9&t=11121
Imaging Diatoms (Royal Botanic Garden Edinburgh) for the ADIAC Diatom Image Database
https://www.rbge.org.uk/collections/online-resources/
https://websites.rbge.org.uk/ADIAC/pubdat/prepro.html
Interestingly they use Brightfield, though I think that COL would probably serve them better.
"All diatoms are photographed using brightfield optics only. There are illumination systems that offer better contrast (phase, and differential interference contrast)¸
but it was decided not to use these since they introduce artifacts into the image that are very difficult to standardize;
DIC introduces artificial shading giving the impression of directional illumination, i.e. the diatom outline looks quite different depending on the direction of the illumination."
Imaging Diatoms RBGE
Imaging Diatoms RBGE
Zeiss Standard WL (somewhat fashion challenged) & Wild M8
Olympus E-P2 (Micro Four Thirds Camera)
Olympus E-P2 (Micro Four Thirds Camera)