"Colour Droop"
WHAT IS IT?
Colour Droop is the effect seen on video tapes where colours seem
to drop below their correct places and "droop" into adjacent areas, leaving
the top of strongly coloured areas often colourless and non-coloured areas
below strongly coloured ones tinted at the top. This is especially noticeable
on strong reds but normally occurs on all colours equally, being simply
more obvious on reds and to a lesser extent on blues.
WHAT CAUSES IT?
There are two main reasons for colour droop. The first problem is that
normal PAL and SECAM colour decoders use delay lines for optimum colour
accuracy with the inevitable effect of some small colour droop (theoretically
one half of a TV line). Secondly many video recorders use delay lines in
an attempt to improve performance and reduce colour noise but again with
the same effect. Both uses of delay lines are a deliberate compromise to
give you the best overall quality and individually these effects are usually
acceptable but when combined, e.g. by several generations of copying, the
colour droop becomes very obvious and annoying. In fact even single generation
copies of broadcast material can show noticeable colour droop!
HOW CAN I CURE IT?
This is where one of the ACE's clever features comes in. The ACE can move
the colour up the screen by up to 3 lines so that you can line up the colour
part of the picture with the brightnesss (black and white) part of the
picture. This is done with the "COLOUR SHIFT ^" button. When the colour
is correctly aligned it looks much sharper and the picture looks much cleaner.
Simple isn't it!
This feature alone is enough to persuade many of our customers to buy
the ACE - even those with computer editing systems who find it the ideal
solution for correcting colour droop in any non-digital camcorder sources
and on their final VHS copy.
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