As announced in August, this is now my epi-illumination equipment:
1: Aluminium hull, pushed over the short objective 4x and cut by 45° to carry the cover slip 2.
3: Metal plate with a hole to make a detergent-skin by stroking over it with the wetted finger.
4: Black sheet between condenser and table to avoid reflections from below.
5: 3W-LED; the white arrow shows the light path reflected down by the cover slip.
I add a new picture taken with this technique. The interference colours are exactely as seen visually:
