Using a Grey Kard

[Andrew]

I was hoping someone had some experience using a Grey Kard. I am using this for custom white balance on a 40D. I shoot night photos with sodium vapor lighting involved sometimes and am looking for a more natural color. I have tried it a couple of times and when I import the photo with the Grey Kard image, it seems to dissapear after I format the CF card. I thought once I imported the image of the Grey Kard it would stay as my CWB. I guess that is not true, becuase when I go to CWB it says no image. Any help with this sure would be appreciated. Thanks.
Andrew

[CaptainTom]

Unfortunately, once you format the CF card you lose the image it had to refer to. You really need a new CWB every time you use a different lighting set up.
There are several techniques to getting a good CWB. I recommend using a white reference source. It works best for me. Gray cards were originally intended to give a reference for exposure and not necessariy color reference.
Keep in mind that all of these things are related to film cameras of years ago..
With film, we didn't need to worry about color balance until the printing process. We would take a photo of a color card ( it had the whole spectrum of colors ) and then use it as a reference when we made prints.
With digital we are concerned about white balance which is essentially the same. There are some good systems where you put a white filter over your lens and use it as CWB. Or, some that have a target that you shoot and can calibrate white balance and exposure using your histogram...
Lots of options, but the important part is that you are concerned about your images, and trying to get them as good as possible.

Also,, shoot RAW...

[kenw]

(ditto on what Tom says...)

but let me add simply that the image you use for WB is just that: an image. Just like any other image RAW or otherwise, it is erased when you format.

personally, like Tom i find a white subject to be simpler for white balance.

[ramblinray]

The only problem I see with using a white object/subject is that there are so many shades of white. The grey card is a standard color and will give you more uniform results. Of course you can carry one of the targets that have white/grey/black on them and be standardized. Or you can shoot through an Expodisc to get your white ballance. Whatever form of target you use, to get consistent results always carry that object with you and use the same thing for every custom white balance shot. The less variables you have in your process, the more consistent and less complicated your workflow will be.

[Ahh!]

You didn't ask, but, in case someone is curious
1. What they said...
2. Good white thingies to put in front of the lens: Expodisc or a clean styrofoam cup. If buying an Expodisk, get the largest one and it will go over any lens you buy or rent in the future. In anycase, you point it at the light sources, not the subject.
3. Gray or grey, older styles may not be true enough grey or gray from which to CWB. I am told color chip 2121 (or maybe it's 212121) at Bejamin Moore is a cheap alternative, too. Speaking of, white is not white is not white. Go back to the paint store and see...
4. I have some software that likes a black/white/grey card. I use it and like it. IMHO.
5. Camera auto WB. While I find I like to use it for casual stuff, it forms an opinion every time and thus is not as consistent over a whole series in the same light, so, sigh, it can't be used for a string of pics.
6. Raw is your friend, but the assumption is your monitor is color balanced and so are your eyes and skill with correction. One lab used to have CWB problems sometimes. They narrowed it down to Thursdays, in the afternoon. They tracked it back to one worker, then realized that he would go out with the gang for lunch at a mexican restaurant. He was asked to stay in the office one week, and sure enough, problem solved. Go figure. (True story in Texas, btw).
7. CWB will be affected by the light source's stability as well as consistency across the color spectrum. So, trying to get a CWB for example, under those yellow "bug lights" may prove nigh unto impossible...YMMV
8. Shooting in a mixed light source environment is not for the faint of heart, if you are a CWB stickler. As the subject moves around, say, closer to the windows in a church filled with incandecent (tungsten-sortof) lighting, the CWB will change. Likewise, a white wedding dress on a bride will be different on the left and right sides. Or the top or bottom of the shelf formed by her "curves".
9. Lastly, there is style. Some photogs are deliberately warming their images. Or, they balance for the daylight and allow tungsten lighting to add accent areas in architectual images...mixed lighting can be your friend...

Enjoy!

[kenw]

for white balance any shade of white will do, as long as it has no COLOR. After all, if a 18% grey card will work, so will a 12% or 20% for WB (but not exposure!).

Incident light meters supposedly use 12%, or so i've read. why i dunno...

Black would work too for WB to but it's a bit harder to get light to bounce off of it. and it's rarely true black anyway.

[Andrew]

I would like to thank everyone for their responses. Some great ideas. I am shooting aviation photography, at Bush Intercontinental mostly. I will include a couple of examples, the first one is shot where there is heavy sodium vapor lighting, shot in RAW. I am using DPP, using color temperature, and still having to use the color wheel to get the aircraft to somewhat of a natural color. This was VERY orange before the edit. This location is where I wanted to try the grey card. Does anyone think I would have better results using either a white or grey card? The second example was shot where there is mercury vapor lighting, so much easier! I always shoot raw, and did not have to mess with color temperature at all, just had AWB set. Sodium Vapor Lighting is sure a challenge! Again I appreciate everyone's help!
Andrew

http://www.airliners.net/photo/Emira...-LR/1319611/L/

http://www.airliners.net/photo/Conti...824/1354310/L/

[The Loft Studios]

Hi Andrew,
Another option you can do depending on your Camera's features is to use one of your Custom Settings. Most Cameras have the ability to store one or more Custom Settings. Say for instance, you stated that you shoot a lot at IAH. Once you Custom White Balance your scene, you can save that in your Camera's Settings to pull up and use again in the future (again, this will be dependent on if your camera has this feature or not). If it does, the next time you go out to IAH, you won't need to Custom White Balance with a Calibration Card (weather that be White, Grey, or whatever your preference is), all you'll simply have to do is pull up that Custom White Balance and start shooting.

Good Luck.....

[3n-Out]

6. Raw is your friend, but the assumption is your monitor is color balanced and so are your eyes and skill with correction. One lab used to have CWB problems sometimes. They narrowed it down to Thursdays, in the afternoon. They tracked it back to one worker, then realized that he would go out with the gang for lunch at a mexican restaurant. He was asked to stay in the office one week, and sure enough, problem solved. Go figure. (True story in Texas, btw).

I have heard of Mexican food messing you up bad, but to mess up your white balance? LOL - I think it was the Margaritas

[CaptainTom]

Originally Posted by The Loft Studios

Hi Andrew,
Another option you can do depending on your Camera's features is to use one of your Custom Settings. Most Cameras have the ability to store one or more Custom Settings. Say for instance, you stated that you shoot a lot at IAH. Once you Custom White Balance your scene, you can save that in your Camera's Settings to pull up and use again in the future (again, this will be dependent on if your camera has this feature or not). If it does, the next time you go out to IAH, you won't need to Custom White Balance with a Calibration Card (weather that be White, Grey, or whatever your preference is), all you'll simply have to do is pull up that Custom White Balance and start shooting.

Good Luck.....

I'll have to respectfully disagree with this concept. Every light has its own color temperature. If you shoot a plane on the same ramp on a different night, and it is lighted by exactly the same lights, the color temperature will still vary if slightly. If you move to a different side of the ramp, the color temp will be different. Even the same exact single light bulb color temperature will vary according to the voltage, temperature, life span, etc.
Think of expensive studio lighting vs. inexpensive studio lighting. What makes the expensive stuff better ? Consistency !! The light intensity and color doesn't vary from exposure to exposure.
I'll be giving a class on this kind of thing in the future...but that's another thread entirely.

[Howard Barlow]

First time I had to photograph an office full of peeps, I set everything up. Background never changed, lighting never changed, subject to camera/light distance never changed. Shot on auto wb. The background in every image was different. Only variable was the individual and clothing. Fortuanetly, I did take a shot of the blank background, as I had to extract each one, about 15 people, and put on that bg.

Live and learn. Or, repeat the same mistakes. In fact, I have some mistakes down to a science, not to mention, an art form.

[The Loft Studios]

Originally Posted by CaptainTom

I'll have to respectfully disagree with this concept. Every light has its own color temperature. If you shoot a plane on the same ramp on a different night, and it is lighted by exactly the same lights, the color temperature will still vary if slightly. If you move to a different side of the ramp, the color temp will be different. Even the same exact single light bulb color temperature will vary according to the voltage, temperature, life span, etc.
Think of expensive studio lighting vs. inexpensive studio lighting. What makes the expensive stuff better ? Consistency !! The light intensity and color doesn't vary from exposure to exposure.
I'll be giving a class on this kind of thing in the future...but that's another thread entirely.

Although this is very true, it's better then always having to constantly color balance using a reference card every night he goes out to the airport. Since he's using RAW, I feel this technique is much more effecient and will get him in the ballpark whereby he can tweak it to his point of view in ACR or whatever Raw Converter he uses...... The same as using the Sunlight dial and/or Tungsten or Flouresant dial on the camera. It quickly gets you in the ballpark to start shooting.

[CaptainTom]

Originally Posted by The Loft Studios

Although this is very true, it's better then always having to constantly color balance using a reference card every night he goes out to the airport. Since he's using RAW, I feel this technique is much more effecient and will get him in the ballpark whereby he can tweak it to his point of view in ACR or whatever Raw Converter he uses...... The same as using the Sunlight dial and/or Tungsten or Flouresant dial on the camera. It quickly gets you in the ballpark to start shooting.

True enough.
He could also set the camera up for a specific color temperature and just leave it there. That way the AWB wouldn't be vacillating around and you could set up the WB in your RAW converter.

So many different solutions to what seems like a simple question.. That's what makes this craft so much fun.

[The Loft Studios]

True..... I didn't think about the customizing the Color Temp.

[Dobick]

If you happen to know the manufacturer/installer of the lights at the airport, you can always find the exact color temperature of the light that they produce, and then dial in both the temp, and the magenta offset in camera. The problem with this is the fact that your shots at this point will not look natural, because even as good as our eyes are at compensating for light colors, street lamps never do look white, even to our eye