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  1. #1

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    Downloadable 18% Gray Card

    http://picasaweb.google.com/VerizzoP...ate/18GrayCard

    My comments:

    This is a gray card created using pure RGB colors in Corel Photo-Paint. I got the settings by scanning a Delta card and then blurring and reblurring the heck out of it. Results? Each color was right around 100 on the RGB scale.

    The spectral range for each color is very narrow on my card. Use it for white balance, too.

    You can make a superior "card" over Delta and Kodak because it has even tonality instead of a lumpy and shiny surface. Put it on a good quality matte paper, or inkjet to fabric! If you use a 90% reflective paper, you now have the flip side of a Kodak Gray Card.

    You will probably need to experiment with your printer settings of paper type and ink load. Make a small image for testing so that you don't waste ink, then when you have it right, print it at full size.

    Don't forget, you just need to get the reflectivity very close, not perfect. There are many other variables of greater concern during exposure determination. I'll bet Delta cards aren't necessarily exactly 18% - but they work fine.

  2. #2
    Ian Grant's Avatar
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    I carry an 18% Grey card with me at all times, it's simpler, cheaper, and free - It's called the back of my hand. Being serious this is an old trick that many photographers use.

    The huge problem with making your own is the type of paper used makes a difference too, it should be matt, then there's knowing if the printer calibrated properly.

    Ian

  3. #3

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    I've got something called a light meter. It's highly accurate. Far more accurate than a piece of grey card which needs to be at very specific angles in relation to the primary light source, subject and camera before it reflects what it claims to reflect.

  4. #4
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    According to my DigitalColor-Meter.app (version 3.6.1) incorporated in my mac, the Grey you showed is : R = 39,2 % G = 39,2 % B = 39,2 % .
    The Grey I have as a desktop background is R/G/B = 17,6 %.
    The Grey in the APUG logo is R/G/B = 29,8 %.
    So, which is the right one?

    Philippe
    "...If you can not stand the rustle of the leafs, then do not go in to the woods..."
    (freely translated quote by Guido Gezelle)

    PS: English is only my third language, please do forgive me my sloppy grammar...

  5. #5

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    I've heard about using the back of your hand.Do you meter and then decrease by 1 stop? Guess it would also depend on your skin tone.

  6. #6
    Ian Grant's Avatar
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    The grey you need is the colour of the clouds on a dull drizzley day in Belgium

    So take your MAC outside & compare . . . . more seriously it's better to acquire a proper card or borrow one and match it, if you really need one.

    Mike, I usually use a Spotmeter, and measure highlughts and shadows, but grass or the back of my hand is usually Zone V, so I can use that. Often if the lights changing very little a I'll just use either for a quick check.

    Ian
    Last edited by Ian Grant; 03-12-2008 at 02:19 AM. Click to view previous post history. Reason: add

  7. #7

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    Following up on what Ian is saying.

    If you're using a 35mm with a built in meter try holding it up to your eye and panning. See how the meter reacts. Let the meter teach you what to look for.

  8. #8
    Steve Smith's Avatar
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    Quote Originally Posted by Mike Kennedy View Post
    I've heard about using the back of your hand.Do you meter and then decrease by 1 stop?
    That's what I do (sometimes). My Weston meter has a line up mark for just this purpose.


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  9. #9

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    Thanks Ian,thanks Nick.
    Another tool in the arsenal.

  10. #10
    Ian Grant's Avatar
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    FWIW just testing my Lunatic Pro meter using the diffuser at the ambient light source is giving the same exposure as taking a Zone V reading off the back of my hand, it's the same in bright sunlight too.

    Ian

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