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Conference hydra::amiga_v1

Title:AMIGA NOTES
Notice:Join us in the *NEW* conference - HYDRA::AMIGA_V2
Moderator:HYDRA::MOORE
Created:Sat Apr 26 1986
Last Modified:Wed Feb 05 1992
Last Successful Update:Fri Jun 06 1997
Number of topics:5378
Total number of notes:38326

3735.0. "rgb->ntsc colors adjustment" by SALEM::LEIMBERGER () Tue May 01 1990 09:46

    	When I digitize a picture with digiview,and then run it
    through the genlock to a tv I don't have the same colors.
    How do you go about setting the amiga up so you get the
    desired NTSC colors? The funny thing is that when I did
    the digitizing the greens looked like a shade of blue.
    So not knowing any better I adjusted the pallette to look right
    on my moniter.Then when I put the picture to video the greens
    are the same shade of blue I started with.This tends to indicate
    that I should adjust my rgb moniter,and redo the pic.So before
    I jump into this I thought it would be better if I had hints
    ect from some of the more experianced video people.Now I understand
    that rgb,ntsc are always going to be different,but I also know
    there must be a way to compensate for this.Any ideas??
    							bill
    
T.RTitleUserPersonal
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3735.1No Adjustment -Lots of light seem bestRIPPLE::LUKE_TETue May 01 1990 15:2913
    I usually don't adjust anything.  Pictures I digitize usually have
    too much red and blue on the RGB monitor but look fine when output
    to a TV/VCR.  In other words, in almost all cases, doing nothing
    to the color palette makes the best NTSC picture, even though it
    doesn't always look quite right on the Amiga monitor.  Of course,
    this assumes that your are using correct lighting (florescent lights
    if you are using the Digiview filter which is thin cellophane, or
    regular bulbs if you have the older thick plastic filter).
    
    Of course, if you still aren't satisfied with the colors, hook up
    a composite monitor while digitizing and you can see exactly what
    colors you are getting.  
    
3735.2thanksSALEM::LEIMBERGERTue May 01 1990 15:584
    thanks for the tip on the lights.I had the thin cellophane filter,
    but moved to the old style when I put on the digi-droid. Will try
    again tonight.
    								bill 
3735.3broadcast is even worse than cableMILKWY::JANZENTom 228-5421 FXO/28Tue May 01 1990 20:4729
    An expert in a magazine article said 
    the colors are too saturated on the Amiga.  He said avoid colors
    with component values over 13 (don't use 14 and 15).  NTSC (national
    television standards intitute, or never-the-same-color) is not very
    tolerant of the Amiga chrominance output.  The white is not necessarily
    very good either.
    Anyway, adjust your RGB monitor for color against a picture of pure
    red,   (R=15,G=0,B=0)
    green,  (0,15,0)
    blue,   (0,0,15)
    cyan,   (0,15,15)
    yellow, (15,15,0)
    and magenta 15,0,15
    white (15,15,15)
    and black (0,0,0)
    Black should be black, you know, no light coming from that part of
    screen.
    I set my monitor for about half full brightness and color just below
    bleeding into other pixels.
    Color bars made on an amiga don't come very close to NTSC color bars,
    even on a good genlock.  But you can avoid distortions

    When I transfered some Director-controlled stuff at a big local cable
    station, the bars were wrong on the vector scope but the engineer knew
    how to adjust it because the bars showed where I was trying to go.
    It came off OK.  Of course, HAM rendering programs may not allow you to
    avoid particular colors, they choose the colors they want to.
    Wish I hada vector scope.
    Tom