I'm shooting a short film in a few months in which the director wants a small scene with BLack lights. The example he gives is from the show CSI and how they're use of black light. I read some of the archives and still was wondering about a couple of things. So you need a UV to not fog the film and you have to use a spot meter because it is all reflective light? Question though no one really talked about film speed, is faster better in this situation? Also does anyone have any results in mixing this light with tungsten day light etc... Would love to get anything people have that I could test out in the next month or two.
>I'm shooting a short film in a few months in which the director wants a small scene >with BLack lights.
I would start by calling these companies and asking your questions...
Nocturn Ultraviolet Visual Effects (818)255-0620 (800) 936-6832
Shannon Luminous Materials (800) 543-4485 (714) 550-9931
Wildfire Inc. (800) 937-8065 (310) 645-7787
Xenotech, Inc (800) 936-6832 (818) 255-0620
These are some companies that rent Black Light fixtures and I'm sure they will be very knowledgeable about shooting under these circumstances.
Film speed depends on the size of your black light sources, but generally faster is better. I've had good luck with 500 EI film at 2.8, using black light tubes in 4-ft 2 and 4 bank kino flos to light a small set. For a larger set, use a wall-of-light or the commercial black light units. You can mix with tungsten light or day light, but it may dilute the effect, depending on the direction of the non-black light.
Imagine that you have a glossy surface that you wish to illuminate strictly through light sources reflected in that surface. If you added direct light from a certain direction, you could dilute the effect of your reflected image. This is somewhat analogous to black light.
The most dramatic black light situations are dark sets in which certain elements of set or wardrobe glow from the black light.
Test with your actors if possible, and look for unwanted anomalies in their skin, especially around the hair. The part in a woman's hair is the most problematic. By changing the height or direction of the black light you should be able to eliminate these cosmetic defects.
Test the wardrobe. Generally lighter fabrics show stronger reflection.
You can also use black light in an otherwise normally lit scene to punch up something in the shot. For example, I had a wide shot of a woman walking across a daylit room in white silk bra and panties. The added black light tube gave a glow to her wardrobe that worked in the context of the scene.
Metering is a rough guide only. With Minolta or Sekonic spot meters it's not even that. I've had good luck switching on a tungsten light for a meter reading, training my eye to that exposure, then shutting off the tungsten light and adjusting the black light level by eye.
Lowell Peterson ASC
Los Angeles DP
I shot a Black Light sequence recently. It was a transition from a "normal lighting" ( with tungsten + half CTO) to a Black Light effect. I had not money anough for a real work at the lab. Only a straight print so I tested for exposition. I used 4 Black Light tubes and created a chart of my own, mostly composed with white material (polystyrene, white paper, spun, etc...and a gray card for the scale) I moved the sources ( 2 feet from subject, then 5 and ten) and exposed at different values with the common 5279 500 T to be printed and compared. No UV filter (if I remember well the film has already one included on a layer...???). Spot meter didn't work at all for me because of monochromatic light and it was far away from what I could see: a brighter element for my eye was given darker by the spotmeter...but the film gave me back what I saw and not what the meter saw...Note that UV light responds to texture, not to color...so all my whites on the chart were different once UV was switch on. For example I saw a 1/4 tough spun glowing under black light, but when changing to 1/4 from a different brand, it became dark...and you couldn't say before you tested.
The best result was for a shoot at 2 (24/25 fps) with 4 tubes at 5 feet from the subject with 5279. (and I had all the values on the gray scale) Mixing tungsten / uv light I could compare with eye (and you have your meter reliable again for tungsten...) I added blue for fill (tungsten + doubled full ctb...). I tried UV bulbs but they were weeker than expected...so I kept going with the tubes (and thay are cheaper !!)
The model I shot wash painted with white fluorescent fluid on the body...which you could not see with tungsten light, but was revealed when uv light appeared...giving a totaly different vision of the skin....At a certain point I think you may have problems with green in the shadows So, get an exposure as a reference and relie on your eye. I hope I 've been of some help. and please, excuse my english, I'm still working on it...
Student at French National School "Louis Lumire"
In regards to CSI we generally "help" the black light source along. The wand type ALS (alternative light source) is an Omnichrome. This is an actual law enforcement device. It is designed to output several different wave lengths of light detect different proteins. The beam is very bright, but not enough for good exposure as it is generally pointed away from the subject. Sometimes I use our second unit to bounce some fill onto our actor. Other times I use a hand held daylight fluorescent with 1/2 CTB for fill. None of this light is actually blacklight, just colored light that we use to represent blacklight. One of the best "blacklight" cheats is two or three layers of Lee 180 on a Source four.