[Tig] DVNR settings theory and practice -- advice needed
JSnopes at aol.com
Sat Oct 6 22:32:48 BST 2001
I need a bit of advice re DVNR settings.
I'm working on remastering a documentary from the Seventies, with very
pretty 7242 color, and quite a bit of nice grain (much of it was pushed
The original transfer was a flat transfer on a Spirit from the 16mm
interneg (A&Bs weren't practical to work from) to D5HD24P. This was
downconverted (via Teranex) to Digibeta. (The D5HD master is being
stored, not needed now.)
Thousands of dust fixes were done in an Avid (uncompressed).
Then tape-to-tape color correction and noise reduction were done (daVinci
2K, DVNR 1000).
Color correction is beautiful. And the noise reduction looks (mostly) ok
when viewed on a 19" Sony BVM20F1, as it was in the telecine suite.
However, when the same tape is viewed on a calibrated 29" Sony monitor
(component in, from SDI via AJA D to A) three things are apparent.
First, and most noticable: there's a sort of grainy veiling over the
image, mostly on scenes where higher DVNR settings (14 Y, 14 C) were
used. (These were used often. No Y or C prefiltering was used, as the
colorist felt that they are to be avoided.) It looks like a
slowly-moving film of grain superimposed over the image.
Second, (mostly) on scenes with extreme contrast ratios, with, say, a
side-lit face, when the face moves, the bright side of the face and the
dark side of the face will move separately, as if they are shifting
tectonic plates -- the dark side's movement lagging a couple frames
behind the bright side. This can be quite annoying. Again, less visible
on the 19" monitor, but there if you are attuned to it.
Third, no aperture correction was used. This may have been a
misunderstanding, as this colorist rarely does tape-to-tape, but
regularly uses aperture correction on their Spirit-to-tape work. This
results in a slightly mushy looking image -- when I run it through our
DVNR for aperture correction only (a 2 or 3 on H and V settings) it looks
(to me) much better.
So, what I'm really wondering is:
What are the usual limits (i.e. highest settings you'd use) on a DVNR.
To me, from some rough tests, it seemed like a 9 Y and a 9 C was about
the limit (on this grainy material). Is prefiltering something to be
used or avoided?
What sort of aperture correction (standard, not advanced) do most of you
like (both H and V) for material that you've noise-reduced?
Any other advice as to the use and overuse of DVNR? It's a great box,
but can be dangerous if overused. (BTW, purpose of this master is DVD
Anyone used the new DVNR card yet (it's being beta tested now, I hear)?
All advice greatly appreciated.
Jeff "noisy, and grainy too" Kreines
More information about the Tig