ahg@mentor.cc.purdue.edu (Allen Braunsdorf) (08/12/90)
I've got my digitizing stuff hooked to my VCR now and I'm trying to calibrate it properly. The local cable company broadcasts a test pattern continuously on one channel and I'm using that to try to get my color right. My question is, what's right? I know these test patterns vary, but I've seen this one used a lot and thought someone out there might be able to help me. Here's a rough picture: +---+---+---+---+---+---+---+ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +---++--+-+-+--++---+---+---+ | | | | | +----+----+----+------------+ Each outline is filled with a solid color. The bars at the top are greyish- white, yellow, cyan, green, violet, red, and blue. The three boxes are a dark blue, pure white, and a not as dark blue. The rest of the bottom row is dark black. Does anyone know the proper YIQ or RGB values of these areas? Since the color strips aren't pure, I'm not sure where to begin. --- Allen Braunsdorf Purdue University Computing Center cc.purdue.edu!ahg UNIX Systems Programmer
jroth@allvax.dec.com (Jim Roth) (08/13/90)
-Message-Text-Follows- In article <12947@mentor.cc.purdue.edu>, ahg@mentor.cc.purdue.edu (Allen Braunsdorf) writes... >I've got my digitizing stuff hooked to my VCR now and I'm trying to >calibrate it properly. >The local cable company broadcasts a test pattern continuously on one >channel and I'm using that to try to get my color right. Not that I'd trust the accuracy of their test pattern :-) >Here's a rough picture: > >+---+---+---+---+---+---+---+ >| | | | | | | | ... >| | | | | | | | >+---++--+-+-+--++---+---+---+ >| | | | | >+----+----+----+------------+ > >Each outline is filled with a solid color. The bars at the top are >greyish- white, yellow, cyan, green, violet, red, and blue. The three >boxes are a dark blue, pure white, and a not as dark blue. The rest of >the bottom row is dark black. >Does anyone know the proper YIQ or RGB values of these areas? The color bars are saturated at 75 percent of full amplitude. You should see (in IRE units) luminance chroma p-p chroma phase --------- ---------- ------------ gray R+G+B 77 yellow R+G 69 62 167 cyan G+B 56 88 283 green G 48 82 241 magenta R+B 36 82 61 red R 28 88 103 blue B 15 62 347 The region below the bars contains: -I reference subcarrier (303 degrees) reference white, 100 IRE units +Q reference subcarrier (33 degrees) reference black, 7.5 IRE units Also, blanking is at 0.0 and the synch tips are at -40.0 - Jim