[Tig] Bad Bugs

Rob Lingelbach rob at colorist.org
Wed Apr 21 06:48:40 BST 2010

On Apr 20, 2010, at 6:29 PM, Bob Friesenhahn wrote:
> The good bugs are reasonably small and are mostly comprised of gray  
> shades using very few levels.  The CBS and HDNet bugs are good  
> example of "good bugs".

In the annals of color grading in good old days of CRTs, there was a  
client for whom it was deemed necessary and important, to include a  
wafer-thin 100% white line in the extreme left edge of frame, such  
that it wouldn't be visible in the typical home receiver, because all  
home receivers were overscanned, due to the nature of CRTs (vacuum  
tubes that could vary in many interesting ways).  These grading  
sessions were somewhat unique in that the client exited the telecine  
with a completed master for air.  The white reference was intended to  
trick the home receiver AGC circuits into not varying the Average  
Picture Level (APL).

Today CRTs are endangered, and new LCDs or plasmas will show the  
entire frame, so the previous method is rendered moot.

Rob Lingelbach
rob at colorist.org

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