Next week I will be shooting a scene under fully fluorescent lighting. I'm fully up to speed on what it takes to balance my flash to the fluorescent white balance by adding a plus green gel to it.
However if I needed that backlight to shift blue, its just as simple as removing the green gel? Or do I need another color to get my backlight to shift blue?
I'm not sure if I am asking the question properly but I basically want to start with a neutral scene and add a tick of blue highlight to the background. Not sure if there's an extra step needed under the fluorescent lighting to correct for to make that happen. Maybe its using only a half cut of green gel?
Once you gel your flash to match and dial in the correct color temp in your camera, you can then add a blue (over the plus green on the backlight). You're going to cut intensity on that particular flash, so dial up the power accordingly.
I would start with a 1/8th plus green on the backlight, since you're going to shift it to blue. Then try 1/4 blue. This way, you'll get less of a blue green, and more of a natural looking blue in the scene.
I did a lot of photography when I was a commercial photographer. When shooting large areas, often there was just no way to light the entire scene. The problem is that there are many variations of fluorescent lights, eg cool white, warm white, etc. Cheap bulbs were the worst, they tended to be very green. Unfortunately, maintenance departments would replace bulbs with whatever was on sale, so there may be three or four different types of bulbs. I used a Minolta color meter to WB and since I was often shooting transparencies, I had to get it right in camera. That's a long winded way to say a generic green for fluorescents might not balance correctly to ambient.
If I understand your question, you want your flash to be neutral and ambient to be a little cool. When gelling your flash, add a warm filter to your green gel, then correct in post for greenies and to make the flash illumination neutral. That will push the ambient blue. I good target like WhiBal would help make the post work easier.
Skarkowtsky wrote:
What D and I should have asked is whether or not people are in the photos??
Absolutely. Good catch. Also, a slight clarification for the dimwitted (me) might help. Is my assumption you want the ambient to go a little blue correct, or did you mean some other source?
I'm assuming it's going to be a two-three light setup. "Natural" key and fill, with a blue backlight that may or may not be on the subject, but definitely illuminating the background.
I am photographing a person. The room is small and completely flourescent. My intention was to balance my fill flash for the ambient which I would probably underexpose by about a stop. Now behind my subject is a window (visible in the frame) with a much brighter florescent lit room that will probably end up being right on for exposure, hence the need to balance for that brightly lit background visible behind my subject. Since my room is so small my idea was to use a blue tinted backlight to thow some color behind him and illuminate some of the tech going on around him.
Hopefully that makes sense.
Also, on a related note. Is there a certain shutter speed to aim for in regards to catching a full cycle or whatever? I thought I'd read somewhere to shoot 1/60, or 1/125 in order to get the most accurate color.
The room through the window might not be as bright when you stop down your lens to compensate for flash power. If that's the case, you might not have to over compensate with the backlight. You might even need to throw a flash in that back room to bring up the lighting, optically.
Gelling flash for fluorescent is a crap shoot. You can get some idea of what color temp they are relative to flash by putting the camera in Flash WB mode, taking a shot and looking at the color. But even then selecting the gel to match is a trial and error process.
I use a bifurcated strategy shooting wide establishing shots with the ambient... http://super.nova.org/TP/State02.jpg
... then overpowering the ambient for closer shot... http://super.nova.org/TP/LightingDiagram.jpg
I used a third flash for the background when doing a story about the kitchen volunteers at our church and for some of the shots I used multi-layer blending with mask with each layer color balanced for the flash, fluorescents beyond the range of the flash, and the tungsten lit food serving stations... http://super.nova.org/TP/MAG_food.jpg
In the shot above I had a flash on bracket and one out in the hallway behind the couple being served, then and balanced the lighting in the hallway on the right and background of the kitchen inside lit with the yellowish renderd fluorescents best I could with blended layers.
In the situation you describe a solution, assuming you have enough flash gear, would be to turn off the fluorescent lights completely and bounce flash off the ceiling or use a bare bulb or cap diffuser flash hidden in a corner. As shown in this set-up shot where I used bare bulb a single light bouncing off white walls can light the room evenly like an overcast day.
http://super.nova.org/TP/Ray02.jpg
The headshot above was taken in an 8 x 14 fluorescent lit office with this: http://super.nova.org/TP/DIYdiffuserCamera.jpg
I stood on a chair with the top of the diffuser pressed against the ceiling for maximum spill fill in addition to direct "key" component hitting the face at a downward angle creating the "butterfly" highlight pattern. I turned off the room lights to avoid mixed lighting.
