Moderators: rjlittlefield, ChrisR, Chris S., Pau
These are darkfield. The turret in my condenser has 4 interchangeable locations (and a brightfield position). I have DIC prisms in three, but in the 4th, I have placed a black darkfield "stop". (To see how I determine the best size for these "stops" check this post: http://www.photomacrography.net/forum/v ... hp?t=10839 ) The actual stop disk used was covered with that Protostar light "trap" material (The less reflective the stop, the better for darkfield). When properly exposed for a "white" subject like this, the background typically measures about 3,3,3 (RGB) in Photoshop. (Exposure is important... many darkfield shots you see are over-exposed). But (full disclosure!Can I ask how the first three were illuminated to get such detail and 3D effect against such a velvety dark background?
) darkfield backgrounds often need "clean-up". If the the water is very clean this may consist of cloning out or "spotting" a relatively small number of bright spots. Water that is full of tiny pieces of debris require more extensive measures. First I'll measure the black level of the background. Then put a blank layer under a duplicate picture layer in Photoshop, and "fill" it with that measured black value (you can also add a little "noise" to this layer to better match the noise levels of the black areas of the picture). Then I can either "erase" or use a mask on the top picture layer to have the black layer show through. 
I sort of knew about the under-exposure tip, but your use of the layer technique to get the background right is also new to me. (Memo to self: must really try to properly learn about Layers in Photoshop! 
) 
