[QuadList] WRC B/W to Color Quad tape

[James Snyder]

Has anybody taken screen grabs of these various moire patterns and 
what produced them?  It would be a really helpful diagnostc tool for 
the community if we had them on a web page with descriptive 
paragraphs.

If sombody has and has them posted, please forward the URL.  If 
someone has pix they can share, I can get them on a web page.  High 
rez screen shot or a direct raster grab preferably.

James

------------------------------------------------
James Snyder
Senior Systems Administrator
Library of Congress -
   National Audio Visual Conservation Center (NAVCC)
Motion Picture, Broadcasting & Recorded Sound Division (MBRS)
Packard Campus for Audio Visual Conservation
http://www.loc.gov/avconservation/packard/


>----- Original Message ----- From: "Charles Park Seward"
>>
>>I have a question about the early color recordings. I have some low 
>>band color recordings from the middle 60s and I see a lot of 
>>herringbone interference. Is that because of the frequencies they 
>>used? Is there a way to clean that up?
>
>Hi Park:
>
>Will be interesting to see what Ken and others have to say.  The LBC
>standard does exhibit moire which was one of the reasons for the move to
>HBC.  As far as I know, there's no way to get rid of it, but there are
>several things to evaluate in order to determine if what you are seeing is
>"normal".  First of all, take a look at the video in EE mode with LBC
>selected as your standard.  The moire that you see should be the "normal"
>amount that would be expected from LBC.  It will be dependent on the content
>of the video, and can be most easily evaluated with a steady signal such as
>color bars.  As a further test, you can compare two different machines in EE
>as a check to be certain that there's not a problem with the signal system
>since they should produce the same results.
>
>The second part of the problem relates to how the tapes that you have were
>recorded.  If they are first generation, they should essentially look like
>the EE signal (as far as moire is concerned).  But if they are second
>generation or later, and if they were video dubs from LBC masters, then the
>moire has been recorded into the video signal, and it will appear along with
>any moire that is a product of the LBC demod, so that the amount of moire
>will exceed the "normal" amount that you see in EE.
>
>Another possibility if your tapes were recorded in the mid 60's and they are
>dubs, is that they could still be first generation as far as the LBC
>standard is concerned.  After HBC became available in '64, it was common to
>have a HBC master that was then dubbed to LBC for distribution to stations
>that were still largely equipped only for LBC.  That practice continued for
>a number of years, so you can have a tape that is a dub but is only a single
>generation of LBC.
>
>Don
>
>
>
>______________________________________________
>Please trim posts to relevant info when replying.
>
>Change subject to reflect thread direction. Thanks.
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