This problem seems to discuss a lot... but no limit. I have two choices right now, Canadian Tire's.
48" Black Light Tube 40W, $25/b and
Black Compact 13W bulb, standard screw, $7/b
I just contact 8x10 maximum size, so.... what is economic choice for me? I think I can make a box with 6-9 bulbs of BC instead of a rank of long tubes (except I am going to contact 24"x36" or bigger sizes)
By 13W, I don't know how long I have to wait for a 8x10 cyanotype sheet completed.
Sorry, I don't want to get 1000W metal halid bulbs, tubes...just economic!!!