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Old Jul 21, 2006, 3:53 PM   #1
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I went to search for a 18% gray card in order to adjust white balance of my powershot A-510. but i did not find it.

Can anyone has a idea how to print a gray page using my HP inkjet printer and Photoshop CS2.

Thanks in advance.
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Old Jul 22, 2006, 7:28 AM   #2
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You could go to the library and borrow a Kodak or other guide which have one in there.
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Old Jul 22, 2006, 9:04 AM   #3
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Greetings,

You do not really need an 18% gray card to measure white balance for a digital camera. What you need is a surface that is spectrally (colorwise) neutral and uniformly reflects only a part of the illumination that falls upon it (not specular such as a mirror or polished metal). your camera will meter the surface during the process, so precise reflectivity does not matter. The 18% value is only for exposure which is another concern
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I do not know what sources you have, but, here in the U.S.A. the Office Depot stores sell an acid free white paper (inexpensive) which I use for the purpose and have found works well. I carry several sheets with me in my bag contained in a plastic bag to keep them clean. They are inexpensive enough that a new surface can be had any time.

By all means avoid the commercial Kodak "gray cards". Ironically, they are not spectrally gray. They are a holdover from an earlier era and are designed only for exposure evaluation, not color evaluation. I wasted half a year struggling with this issue until I discovered this fact. To make things worse, the Kodak gray cards are not printed on acid free paper, so, they turn yellow just as old newspapers do.

Hope this helps.

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Old Jul 22, 2006, 10:24 AM   #4
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I use Photoshop Elements 1 to make a gray card. Make a new image any size you plan to carry then open the color palette and use (2E2826) or put 18% into the right boxes, use the fill and there you go. I had it printed at a photo shop.

I have only used it once because I find I just use the colorcast dropper in PSE1 to get the right colors, there is always a spot in a photo that has that pure gray, white or black.

I made a card with white, gray and black in a 4x6 print, when I find the file I'll post it.

Found it, gray(18%?),white and black card

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Old Jul 24, 2006, 5:14 AM   #5
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Thanks to all of you.

Can I make a gray card using Photoshop and print it professionally on 4x6 size.

I try my normal printer sheets for custom white balance and it works quite good. But I don't know if it is acid-free paper or not.

Has anyone used this technique before.
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Old Jul 24, 2006, 9:19 AM   #6
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Greetings,

If your usual white printing paper works OK to set white balance, then, you have everything you need. The acid free characteristic only functions to lessen the probability of the paper yellowing with time, as old newspapers do. How fast that happens depends upon the acid level of the paper. Ironically, the acid is used to bleach the wood pulp to create greater initial whiteness. Just use a fresh sheet occasionally and you should be OK.

You might want to reread your camera manual for the details on setting white balance. I just re-checked one of mine and it actually says to use a "white sheet" and does not mention gray.

Hope this helps.

Richard LS
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Old Jul 24, 2006, 4:49 PM   #7
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thanks for your reply "scaramouche"

my white printer paper qorks just fine for me and it maintains its color for quiet a long time.
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Old Oct 9, 2006, 8:54 PM   #8
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I use a short piece of white vinyl vertical blind slat. Water and sweat proof! Fits in pocket or gadget bag.
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Old Oct 10, 2006, 5:45 PM   #9
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I bought to 8 1/2" x 11" grey cards off e-bay for about $5, one I cut into smaller squares the fit in my pocket the other I use for the studio shots.
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Old Oct 18, 2006, 8:43 AM   #10
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I have just put serveral formica sample chips on a snap ring I picke up at local home improvement store in multiple colors. Using different colors with my WB allows you to simlate different conditions by having your WB readings attempt to adjust to a false color cast.

Also small, waterproof and easly replaced
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