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  1. #11

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    Quote Originally Posted by Ian Grant View Post
    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.
    Ian
    Is that with a sunburn or without?

    I mean, after driving for a whole day in high summer the back of my hand easily goes down to ZoneIV if not darker

    If I have no other good reference I usually measure off the palm of my hand and open up by ~1 stop. The palm tends to stay the same shade.

  2. #12

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    Quote Originally Posted by Ian Grant View Post
    The grey you need is the colour of the clouds on a dull drizzley day in Belgium
    Ian
    Even that is not a stable parameter.

    Did you know that Belgians (both French and Dutch speaking) have about 43 different words to define the grey of the coulds? It's more than Eskimos have to nominate the whites of snow


    G

  3. #13
    Ed Sukach'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? Guess it would also depend on your skin tone.
    Depends upon whose hands we are considering. They are like snowflakes - no two exactly alike.
    The amount of light reflected will depend on the characteristics of the light itself, as well. Compare the back of the hand in question to a gray card in different situations - and see how well they correlate.
    Carpe erratum!!

    Ed Sukach, FFP.

  4. #14

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    "Back of Hand?" and more

    I presume you gents are referring to the palm of your hand. Backs of hands vary widely in reflectivity.

    Yes, that's all my father ever used for a reference point. Set your light meter for a one stop slower film. An amazing fact of nature, no doubt. Doesn't matter what your race is or anything.

    As to paper type and "calibration", that's why I said to run tests. Frankly, I can't imagine an 88, or 92, or even higher paper mattering. It's being covered pretty thoroughly with ink. Test against a known good card, change your saturation as needed.

    I did this just for fun. I also thought it might be useful to have a "card" that folds.

  5. #15

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    Mine, of course....

    Quote Originally Posted by leicam5 View Post
    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
    Just kidding, but not entirely. I can't address the issues cuz I have no idea what your digital color meter is, although I think I can make a fair assumption. Nor am I familiar with rating a color as percentage of RGB. Sorry.

    Certainly your desktop background and APUG logo don't hold themselves out as 18% gray, do they?

    As I mentioned, I find the Delta card, the only one available here, lumpy in texture and rather shiny. I'm probably picking nits, but I can't believe that those characteristics are conducive to accurate readings. When I scanned it, those characteristics showed up strongly as darker and lighter areas.

    After the scan I used the various blurring tools in Photo-Paint over and over until it was as uniform as I could get. I would save it and then reopen it for another treatment. I did this, I think, three times. There was a very slight, barely perceptible ringing on my LCD monitor similar to using 16 colors with an image. Again, barely perceptible, I had to move my head around to confirm what I was seeing. When I opend this in my Dimage Viewer program and hovered my cursor around the "image," the readings were within a point or two, plus or minus, of 100 on the 255 RGB scale. I thought that most interesting!

    I went back to Photo-Paint and dialed in a fill of 100 for each color. And there it is.

    Obviously Delta or Kodak or whomever makes an analog printing ink to meet specs. The colors are rather diffuse around their maximum values, sort of like a steep mountain. It's what I would expect from, er, an analog production. My chart is a sharp spike in each color. Does it matter? I'm sure that the answer is an empatic "No!"

    If nothing else, there's a reference for your monitor.

  6. #16

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    Mine, of course....

    Quote Originally Posted by leicam5 View Post
    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
    Just kidding, but not entirely. I can't address the issues cuz I have no idea what your digital color meter is, although I think I can make a fair assumption. Nor am I familiar with rating a color as percentage of RGB. Sorry.

    Certainly your desktop background and APUG logo don't hold themselves out as 18% gray, do they?

    As I mentioned, I find the Delta card, the only one available here, lumpy in texture and rather shiny. I'm probably picking nits, but I can't believe that those characteristics are conducive to accurate readings. When I scanned it, those characteristics showed up strongly as darker and lighter areas.

    After the scan I used the various blurring tools in Photo-Paint over and over until it was as uniform as I could get. I would save it and then reopen it for another treatment. I did this, I think, three times. There was a very slight, barely perceptible ringing on my LCD monitor similar to using 16 colors with an image. Again, barely perceptible, I had to move my head around to confirm what I was seeing. When I opend this in my Dimage Viewer program and hovered my cursor around the "image," the readings were within a point or two, plus or minus, of 100 on the 255 RGB scale. I thought that most interesting!

    I went back to Photo-Paint and dialed in a fill of 100 for each color. And there it is.

    Obviously Delta or Kodak or whomever makes an analog printing ink to meet specs. The colors are rather diffuse around their maximum values, sort of like a steep mountain. It's what I would expect from, er, an analog production. My chart is a sharp spike in each color. Does it matter? I'm sure that the answer is an empatic "No!"

    If nothing else, there's a reference for your monitor.

  7. #17

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    Sorry for the double post!

    Sorry for the double post!

  8. #18
    Steve Smith's Avatar
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    Has anyone tried using a purely black and white pattern similar to the one attached?

    If you have 18% of the area white and the rest black you should get 18% reflectance.

    A suitably spaced halftone dot pattern should work too.



    Steve.
    Attached Thumbnails Attached Thumbnails grey.jpg  

  9. #19
    RH Designs's Avatar
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    Quote Originally Posted by Steve Smith View Post
    Has anyone tried using a purely black and white pattern similar to the one attached?

    If you have 18% of the area white and the rest black you should get 18% reflectance.

    A suitably spaced halftone dot pattern should work too.
    The problem is - how black is the black and how white the white? This would work with perfect 0% and 100% black and white respectively, but not otherwise. The idea of a grey card is to appear as a mid grey, looking to the eye like half way between black and white. Trying to produce one using an inkjet printer throws up all sorts of issues of colour management, gamma, etc. which are not subjects for this forum and to be honest best avoided by all but the dedicated colour scientist. Anyone who's tried to match an inkjet print to the screen image without using a fully colour managed workflow will know what I mean! Using a glossy paper for a grey card makes matters worse because of reflections etc.

    Best to use your hand or a commercially produced grey card. Better still, a spot meter.
    Regards,
    Richard.

    RH Designs - My Photography

  10. #20

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    My original thinking was along those lines....

    Quote Originally Posted by Steve Smith View Post
    Has anyone tried using a purely black and white pattern similar to the one attached?

    If you have 18% of the area white and the rest black you should get 18% reflectance.

    A suitably spaced halftone dot pattern should work too.



    Steve.
    But I quickly realized what the poster below did.

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