need internal information of the old hercules graphics card (hgc)standard

Discussion in 'Video Cards' started by johannes.black@gmail.com, Jun 17, 2008.

  1. Guest

    I would like to improve the dosbox dos emulator and would like to
    implement black/{green,amber} hercules emulation in the program.

    Does anybody have good information about the hgc internals?
    Additionally I´m interested which colors the hgc green / amber color
    represent in todays 24 bit / 32 bit graphic cards (RGB-value)? Also I
    ´m intersted in the normal afterglow delay in an average hercules
    monitor (from green/amber to black). Get the after glow function
    exponentially or linear to zero?

    Greetings and thanks
    jo
     
    , Jun 17, 2008
    #1
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  2. Bob Myers Guest

    Re: need internal information of the old hercules graphics card (hgc) standard

    <> wrote in message
    news:...

    > Additionally I´m interested which colors the hgc green / amber color
    > represent in todays 24 bit / 32 bit graphic cards (RGB-value)?


    RGB values do not, strictly speaking, properly identify a
    particular color. You need to know at least the specific
    primary colors in question and the "white point" of the
    display, and it would be very, very helpful to know the
    precise response curve of the display before you could
    consider a RGB triple as pointing to one specific color.

    However, for what it's worth - the old "amber" phosphor
    in the monochrome monitors was almost always the
    "P3" type, which may help you find color information re
    that particular phosphor. P3 is a medium-persistence
    phosphor, and you could probably simulate the "fade"
    by dropping the brightness along an exponential curve
    such that you got down below 10% of the initial level
    in, say, 0.2-0.3 seconds. In contrast, the "green" phosphor
    was P31, and had a much shorter persistence.

    Bob M.
     
    Bob Myers, Jun 17, 2008
    #2
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