Paul C. Buff, Inc. Technical Forum

Is there any chance that this flash can produce a red color cast. I have a small studio and my X1600 is not being used anywhere near even half power, with that being said can it produce a red color cast. I'm having my raw files bringing a red color cast from somewhere, even though my camera style is set to Neutral. Any assistance in this would be greatly appreciated.

Depends. First, a red color cast is somewhat subjective based on what you consider "white" light. Are you comparing this light to the color from another light? Are you setting a white balance to 5600K (or flash white balance, for that matter)? Are you performing a custom white balance and seeing a red cast?

The flash tube is designed to be 5600K at full power. As you decrease power via the slider, the color will shift lower (red/yellow) about 80K per stop. Reducing the power with the blue 1/4 power switch does not affect color.

Once you add a modifier to it, it can shift back up, if you are using a silver surface, or down if using a white surface that has not been treated with optical brightners. If it has, then the white fabric can be raised 1000K or more. Our white fabrics stay within 250K per layer, usually within 150K.

So ultimately, it will depend on how you determine the red cast is there as to the explanation of why it is there.

Well said TS

My 2c worth is if you don't have a color checker, shoot a scene or portrait with the single WL flash unit in question. Make sure there is something of pure white in the scene, white shirt for example. Make sure it's exposed very well. Now open the raw file, in most software you can select a point to set your white balacne too. Select the shirt. Now look at what the color temp of that file is. If it's in the range of 5500-6000 the light is not the issue.

That being said, if your using a studio light setup, you have taken the time to set your light angles, exposure, backdrop, etc. why not invest in a grey card? I have a white balance thingy that looks like a small foldable reflector. Cloth with a spring around it so it twists in half the size. Any how, it's grey on one side and white on the other. White is for canon shooters (me) and grey is for Nikon guys. Not sure why canon cameras like white when everyone else uses grey. All you do is set your exposure on your lights the way your going to shoot the scene and first shoot a close up (fill the frame) of the white balance card. Now set your WB setting on the camera to that image.

If you have the cash, a color checker is nicer to use. I have the model hold it up at nose level and shoot an image. It has calibrated color squares that you can use to set WB in post. I like to use the grey square that is cooler that gives the image a subtle warm look.

Anyhow, happy shooting

Overall, good advise, however, a white shirt is not necessarily a good target. While it is close to white, most white fabric and paper has been treated with the optical brighteners I mentioned before. When exposed to UV light, it can glow a blue/purple, and sunlight and flash can have UV in it, though we filter as much UV as practical in our flash tubes.

A good, purpose made color target is the key. We use the Whi-Bal cards, which are really inexpensive, but color neutral. The Kodak gray cards of yore are middle tone, but not necessarily color neutral (they are exposure cards, and a slight color cast is irrelevant in exposure). There are a wide variety of color targets on the market, some great, some junk. The Color Checker not only provides a neutral target, it can also help correct color bias in your camera/lens that is not compensated for with a color temperature correction.