Originally Posted by rangiku (Post 362232)

What is the proper way to take a meter reading for plants? In photography, you meter on the object. Do you take your meter reading on your actual plants or on the area around the plants. Vast difference between the two, especially if you are metering on a white windowsill.

Originally Posted by rangiku (Post 362283)

Thanks for the explanation, Nat. I've been putting off getting lights, but it going to happen soon.

P.S. I still use film: black and white with a 4 X 5 camera shooting and developing using Ansel Adams Zone System. And, I print my own color film.

Originally Posted by BobInBonita (Post 362281)

Gnathaniels absolutely correct about photography measuring light reflected by the subject, whereas in growing we measure the light hitting the subject (the intensity of the source). One idea (using the camera analogy) that helped me understand window lighting better:
Imagine the orchid as a relatively wide angle lens pointing at the light.
When close to the window, the field of view of the lens is completely filled, and it is just like being outside. The intensity is pretty much the same as being outside (unless there is screening or the window is dirty).
Once you get far enough away that the field of view is not filled, the window acts like a point source and the intensity falls off with the square of the distance from the window.