I just started using flash recently, and have never used gels before. I never knew I needed them until I was trying to use fill flash on someone against a skyline, so the colors are off because of the different light sources. This is the setting:
Well what are your White balance settings? If say you are using Tungsten (3200˚K) use a CTO gel, If using the fluorescent WB setting , try a Full PlusGreen.
Or you can just use daylight, letthe background go a weird mix spectra manned maybe using a light warming getl on the flame like a 1/4or 1/2 CTO or Straw.
hollowsparks wrote:
I think the white balance was around 3700K~3800K. should i be using a plusgreen at that point?
You need to filter your flash.
Assuming that your white balance was 3750K and your flash is 5500K you have a mired shift of +84. The closest single filter would be a 'Half CT Straw' at mired +81. Alternatively, two '1/4 CT Straw's' would give you your +84. There may also be an element of Magenta or Green to be catered for which would be in the region of between +10M or +10G depending on accurate readings of your light.
hollowsparks wrote:
I think the white balance was around 3700K~3800K. should i be using a plusgreen at that point?
A PlusGreen gel is to balance the flash to fluorescent lighting, Fl lighting has a rough color temperature and a spiky spectrogram but what the color temperature is depends on the bulb and other factors.
We have an instant proof of every frame with digital, grab a set of gels and go try it, you'll soon see what works and what doesn't, and may even hit across things you never thought of before. (Go overboard on the orange gels and you can turn that whole city blue, etc.) You don't have to chimp, but in settings like this there is no good reason not to.
hollowsparks wrote:
...I was trying to use fill flash on someone against a skyline, so the colors are off because of the different light sources.
The lights in the background weren't significantly contributing to your subject lighting if this was the shooting location. If you were using flash as fill, what was/were the main light(s)? These things would determine what gel to use.
You could, of course, use ungelled flash as the main light(s) on your subject, use a "Flash" or "Daylight" white balance, and let the background go to whatever color it will; the various colors can lend an artistic element. As long as your subject looks natural, a color cast in the BG wouldn't neccesarily be a problem.
I was just using a 430 II on the hotshoe. I had the WB set for the flash, so the subject was fine, but the entire background has an orange cast which I don't like.
Layering portrait with location
Heres another way to think about approaching the problem. It might makes easier on the input side but a little more complicated on the processing side.
From the looks of it, it appears the background need relatively long time exposure at the aperture & ISO settings you have decided to use, between that and from how crisply the background is rendered, you probably have the camera on a tripod. Also we dont know the ambient existing light situation on your side of the harbour or river. It may be that the existing light where you are posing him or her, in combination with the flash is what is messing up the color on their face.
So set up your shot again, focusing on the sitter, and switch to manual focus. Light the sitter the way you want but dont gel the light. And use a short enough shutterspeed so the ambient light on him or her is just a slight factor but not so short it is no facto. It will be important that you dont move the camera but the sitter can move. Try to keep them at the distance you've focused at. After you shot a range of expressions and are happy with that, have them move out of the picture and keeping your aperture the same, make a bracketed series of exposures for the background. Hopefully you are shooting raw.
Back at your studio, after selecting the best expression and the best background, and doing the raw processing, open both in Photoshop as seperate documents, do a simple selection of the portrait, copy it, and paste it as a new layer on the cityscape. You'll probably need to clean it with a little masking so the parts of he background in the portrait dont interfere with the cityscape layer.
To go a little further if, both images are Smart Objects you can refine color balance in ACR on each layer if you are working in Photoshop CS 4 or 5.
Its just another way of thinking about the problem you are trying to solve.
hollowsparks wrote:
I was just using a 430 II on the hotshoe. I had the WB set for the flash, so the subject was fine, but the entire background has an orange cast which I don't like.
Got it.
The above suggestions for filters are great. If you don't want or need to be that precise, then you could go with just about any yellow filter to get in the ballpark, and then make the final correction in post processing. I often do this when shooting indoors in people's homes by matching my flash to their household lamps by using a Sto-Fen Gold Omni-Bounce cap over my Speedlite. It's not as precise as using the exact filter pack for the conditions, but it's so close as to be indistinguishable in most cases.
Taking one shot with your subject holding a gray card or other color reference will let you make a easy adjustment in PP, and you can then use the same adjustment for all other shots under the same lighting.
If you saved the shots you took that you didn't like, it's not too late to make them better. Ellis' idea for making composites would work well, even using the shots you already took. Here's how:
Make two versions of your best shot, and adjust one for subject color and one for background color. Then, select the adjusted subject and put him or her into a new layer on the adjusted background. Finally, merge the two using layer masks.
While I'll agree that using photochop is one way there is certainly something to be gained by understanding mired color correction and doing it in camera.
i understand how to do it -- idid it for a couple of decades with film work, during my first eight years of digital work, but there is also a lot to be said for deliberately deciding not to work with one hand tied behind your back.
I still think people are best shot in specific locations - there is a real emotional vibe to it for the sitter and photographer as they react their surroundings and this shows up in a photo -- as opposed to green screen portrait shooting and then compositing later. But color balancing of this sort is a mechanical act -- he is trying to fix something he thinks is wrong with his photo. While color balancing can also be creative in nature it is still a matter of choosing between tools.
I like it!