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this works??

Discussion in 'Just for Laughs' started by cazzam35, Dec 5, 2005.

  1. cazzam35

    cazzam35 Kilobyte Poster

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    Open this image up in photoshop or paint pro and check out
    the two squares, they ARE the same colour!
     
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  2. tripwire45
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    tripwire45 Zettabyte Poster

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    You're blind. No way are square A and square B the same color. :blink
     
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  3. Jakamoko
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    Jakamoko On the move again ...

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    Sorry Trip - it says the same in my daughter's optical illusion book. It's true :)
     
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  4. cazzam35

    cazzam35 Kilobyte Poster

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    as it says trip, open up the image and use eye dropper tool
    to pick a colour and they are the same!

    I use photoshop daily so as soon as I saw this thought what
    a load of rubbish, but they are.
     
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  5. JonnyMX

    JonnyMX Petabyte Poster

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    Hard to say.
    If you scroll the eyedropper around both squares, you actually get a range of colours for each. Although there is an overriding similarity, there are enough 'other' pixels in there to make it a bit dodgy...
     
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  6. Bluerinse
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    Bluerinse Exabyte Poster

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    Well I was always taught that black and white and every shade of grey in between are not colours, they are shades.

    On a monitor there are no black or white pixels. White is made up from a combination of red, green and blue. The ratio of luminance between these three colours is what gives the white balance.

    So my guess is that the ratio of red green and blue is the same but that the luminance factor creates the impresson that one square is brighter than the other. :dry
     
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  7. cazzam35

    cazzam35 Kilobyte Poster

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    You took the words out of my mouth blue :blink
     
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  8. Veteran's son

    Veteran's son Megabyte Poster

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    Excellent explanation, Bluerinse! :)
     
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  9. _omni_

    _omni_ Megabyte Poster

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    yes, both squares are the same "color" (107). the only slight difference in some pixels is caused by jpeg artifacts (due to compression).

    RBG goes from 0 - 255, if you have equal amounts of each than you get white, black, or grey.
    and the board is in greyscale so naturally there are equal amounts of RGB.
     
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  10. Bluerinse
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    Bluerinse Exabyte Poster

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    They don't have to be equal exactly, it depends on the white balance that you are after. Check this link and you will see that the white balance named snow is all equal but the other temperatures of white vary...

    http://www.pitt.edu/~nisg/cis/web/cgi/rgb.html
     
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  11. _omni_

    _omni_ Megabyte Poster

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    hmmm...i'm not really sure what your point is.

    regardless of white balance and the many other factors that determine a pixel's color, it all comes down to:
    R 0-255, G 0-255, B 0-255. (24-bit)

    the fact is, they do have to be in exactly equal quantities to be neutral.

    just because something looks grey doesn't mean it is necessarily grey. it could be R 128 G 128 B 129, that would look grey but it wouldn't technically be grey.

    unless you are talking about CMYK, that color space is subtractive and therefore works differently.
     
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  12. Bluerinse
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    Bluerinse Exabyte Poster

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    Okay let me explain, you said this...

    And I am responding to the above statement, simply to add another dimension which you may or may not be aware of.

    My point has nothing to do with computers as such. I am talking *addative* colour mixing, something which I have been involved with for years. I studied Radio, TV and Electronics for five years and as part of the TV component of the course we were taught about RGB colour mixing. I worked as a colour TV engineer for eight years and I worked with digital colour copiers for many years after that.

    Basically, in layman's terms, what I am getting at is this. The human eye does not respond to colour (red green and blue) in equal levels and the red green and blue phosphor dots on a CRT (cathode ray tube) do not give off equal amounts of light, given the same situation. i.e. they do not illuminate equally given the same cathode, grid, screen grid and anode voltages. So in order to make it appear to the eye that they are equally bright, they are given different levels of brightness or a bias if you like.

    From memory the ratio is, Red=.3 Green=.59 Blue=.11 this gives a luminance of Y (white)

    This is happening behind the scenes so to speak. So when you set a colour to 255 255 255 that gives snow white but in reality the pixels do not get equally lit :eek:
     
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  13. _omni_

    _omni_ Megabyte Poster

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    ok but see i've worked for years with photoshop and i've studied color spaces from a graphics POV.

    now what i'm getting at (because i'm stubborn) is that for example, RGB 128 is midtone grey. now on your monitor you might see blue or red, but that doesn't change the fact that it is grey.

    as far as i understood from your above post, you try to make i.e. white = *a certain ratio*, red = *a certain ratio* etc, so that the colors will look right on the TV. granted, i don't know about that stuff on TVs.

    but on monitors, you have to calibrate them to conform as much as possible to what you know to be the true color, which is why you buy color swatches for comparison.

    in the end, it doesn't matter what it looks like to you, as long as you know what the color really is. because there will always be differences in the way different monitors display the colors, and in what different eyes will see.
    maybe it will look more neutral to you if you add a bit of blue, but you will have changed the true color.

    what you see is relative, but what it IS is absolute.


    i've got some nice books by Michael Kieran who happens to be a bigwig in the "color world", thats where i learned most of my stuff from. ;)

    I WILL FIGHT TILL THE END!!!! :D
     
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  14. Bluerinse
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    Bluerinse Exabyte Poster

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    :box2 Bring it on big guy :D

    We are both talking about the same thing here which is good. I am just trying to explain the mechanics of what goes on with the phosphor dots on a monitor. The electronics of the video circuitry inside the monitor do all the work for you. The monitor is calibrated to show proper grey scales out of the box.

    You are talking about what happens on top of that. It's a bit like the OSI model, things happen at different layers. You are talking about end user control through an application. I am talking about RGB displays.

    So, rather than fight, we should learn from each other and try to see a wider perspective.

    Or we could switch the conversation to subtractive :eek:

    :D
     
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  15. cazzam35

    cazzam35 Kilobyte Poster

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    come on children lmao!! :argue
     
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