WB and grey cards

Discussion in 'Beyond the Basics' started by Johnboy2978, Mar 15, 2006.

  1. Johnboy2978

    Johnboy2978 No longer a newbie, moving up!

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    Hey guys, I've noticed that when I am shooting indoors particularly with fluorescent light, I have a very difficult time getting the colors correct. I've tried different setting with my camera including auto white balance, as well as the ones for indoor lighting, and it's close but still too far from being right. People come out looking jaundiced usually. I tried using a sheet of white mat board that is completely white for the manual wb adjustment, as the manual says to either use white or grey to adjust it manually which gets closer than any other setting. Do the 18% grey cards make that much of a difference? They're quite expensive for what they do, or can you get by using something else? What do you guys use if you use something different?

    Thanks
     
  2. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    As far as I know...anything white can be used to set a custom WB. A card, some paper, a white shirt or piece of clothing.

    I've heard that a grey card will work as well....but I still don't understand why or how. Grey cards however will also work for metering to set your exposure.
     
  3. darich

    darich TPF Noob!

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    I've never used a custom white balance but my understanding is you take a properly focussed shot of something white in the lighting conditions you intend to use the custom setting in and then tell the camera that that images should be white. It then adjusts all subsequent shots accordingly.

    Not sure about the grey card.

    As for the jaundiced look - i know exactly what you mean - I've been there!! If every image is shot in the same lighting conditions, then adjust one in photoshop while recording an action, then simply use that action on all the remaining shots. It should work pretty well since the lighting in all shots will be the same and hence the adjustments in all shots require to be the same.

    Might be wise to keep the jaundiced originals just incase you don't like the auto adjustment of the action and can go back and manually adjust it.
     
  4. Soocom1

    Soocom1 TPF Noob!

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    IF, and I mean IF your camera has the ability to set the Kelvin Temp, set it with a series of test shots. Each set of Fluorescent bulbs is different.

    Heres the problem: Fluorescent bulbs come in a variety of flavorers. Ranging from 2500 to as high as 6500K and higher. The problem with FBs are that they progressively get different temperatures as they age. Thus a bulb rated at 2500 K when new can go to a 2700K or a 2400K just before they go out. (Which can be many years.)
    Also those bulbs are not replaced as sets, EVER! So the temperature in Kelvin can be dramatically different from one side of the room to the other. (This is why you test shoot in the center of the room).

    Another problem is that in most (group meeting rooms) aka Ball Rooms in Hotels, and the like are different from offices, different from grocery stores. In offices the FBs come in what is known as "Natural Light" which is a mixture of different K rated bulbs. One is redder and one is bluer. This helps reduce eye strain in the office. In grocery stores it is deliberately redder in the meat section for obvious reasons. (Makes the meat look more appealing). In the clothing dept., think vanity. Cooler lights are more flattering in contrast for colors of various clothing... Ala the ladies... (No offense meant here.)
    So, you have to watch that problem.

    Now. For the solution to most of your problems, again this is a very BIG if: If your camera comes with a photo processing software, use it! By finding an off white item, then hitting the little white adjust in the program, or even in Photo shop, the colors will come out allot better. just keep in mind, that they will never be DEAD SPOT ON for any shots taken in fluorescent lighting. Particularly if you have a mixture of ambient light.

    So go fourth and photo more...
     
  5. Johnboy2978

    Johnboy2978 No longer a newbie, moving up!

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    Actually, I mis-spoke in my original post. I said fluorescent however, I imagine that most standard lightbulbs that would be found in a standard table lamp would be closer to tungsten kelvin rating. At any rate, I was using the AWB setting on my camera's WB setting which produced very jaundiced pics. The tungsten setting was better, but not close enough to "true" color. I noticed in the manual that the AWB adjusts for 4000-8000K while tungten is rated at about 2850K. So this probably explains why AWB is not the setting to use when shooting indoors say, in your living room.

    By using the manual WB adjustments and shooting at a white mat under the same light, I got results I can be happy with. So when in doubt, I'll just carry a 4x6" piece of mat board with me I suppose.

    Thanks guys.
     
  6. Rob

    Rob TPF Noob!

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    Newspaper is very close to 18% grey. ;) Use that instead!!

    Rob
     
  7. Torus34

    Torus34 No longer a newbie, moving up!

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    First, gray cards expensive? B&H stock # DEGC is an 8" x 10" gray card at $us3.50.

    Next, fluorescent tubes do not have a continuous spectrum. The sun and incandescent bulbs do. A discontinuous spectrum means that some of the 'colors' are missing in the light itself. Even with careful balancing, there will still be problems in rendition of certain parts of the spectrum.
     
  8. Johnboy2978

    Johnboy2978 No longer a newbie, moving up!

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  9. Torus34

    Torus34 No longer a newbie, moving up!

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    You can always buy a Ferrari when all you need is cab fare.
     
  10. Richard King

    Richard King TPF Noob!

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    I have been known to white balabnce my camera with a grey card on the fly between each shot, or at least every 10 miniutes. this wa especially useful at my last wedding with a venue with nice yellow and orange walls and different lighting in every corner!
     
  11. clarinetJWD

    clarinetJWD The Naked Spammer Staff Member

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    You can shoot in RAW, right? Just do that and correct it in RawShooter or something like it. spot on WB every time.
     

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