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Thread: Color HElp!!

  1. #1
    SitePoint Wizard dethfire's Avatar
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    What does 16-bit, 24-bit, and 32-bit colors mean and what is the difference. The eye can see 16 million colors right?
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    SitePoint Addict Drinky's Avatar
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    The total ammount of colours the human eye can see varies from person to person, but is all roughly similar. Unless you have an eye defect.

    That referes to the number of bits needed to store a colour pixel. The more bits you use the larger the number of colours you can store.

    An example that you'll be familiar with is web colours represented by 6 digit Hex numbers. e.g.: #FFFFFF

    This colour value represents three values for the colours Red Green and Blue, 2 digits per colour. So Red = FF Green = FF and Blue = FF which makes white (since red green and blue at full intensity mix to make white).

    When converted to decimal the value of FF is 255,
    When you convert the decimal to binary 255 = 11111111

    This shows you that to store the Red value for the colour you need 8 bits (or one byte). You also need 8 bits for the Green and 8 bits for the Blue values.

    Therefore to store the pixel colour white (Hex: FFFFFF / Dec: 255 255 255 / Bin: 11111111 11111111 11111111) you need 24 bits.

    since RGB values can be anywhere from 00 to FF (Hex) or 0 to 255 (Dec) there are 256 possible values for Red, 256 possible values for Green, and 256 possible values for Blue.

    So you can work out the maximum addressable colour range for 24 bit colour by multiplying these values together so

    24 bit colour can display (255 255 255) = 16,581,375 colours.

    16 bit colour can address roughly 64,000 colours

    36 bit colour uses 12 bits per colour (R:FFF G:FFF b:FFF) (4095 4095 4095) = 68,669,157,375

    32 bit colour is reffered to as true colour.

    Although what you can see and what you perceve colour wise varies amazingly, I have a few examples of this which i will post later, when i dig them out.
    Drinky

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    SitePoint Addict Drinky's Avatar
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    I should have said that my example uses the RGB colour model.

    Since there are several colour models you can use to display colour:

    Model -> what it's made of

    CMYK -> (Cyan Magenta Yellow blacK)
    RGB -> (Red Green Blue)
    HSB -> (Hue Saturation Brightness)
    Lab - > (Chrominance, Chrominance, Luminance)

    Also:
    16 bit colour is useb by CMYK and is the colour model used by printers (bubble/ink jet, laser, but Not Dye Sub).
    It takes the form (C, M, Y, K) Hex: F F F F / Dec: 15 15 15 15 / Bin: 1111 1111 1111 1111 = white
    Drinky


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