[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

HELP! on monitoring

Very interesting discussion this. Real can of worms and some good replies too!

As usual Mr. Corbitt provides extensive and well researched replies. On his
question 7 I would like to offer a reply, it may be that Barcos are just not any
different from other manufacturesr of Grade 1 monitors because they all use the
same (Matsushita?) CRT supplier. The only exception beeing Sony of course. Sony
ARE brighter because the fundamental design gets away with a beam reducing mask.
I think these non-Sony monitors are simply set to not be too bright as to
provide a better detail response.  PERCEIVED resolution is a factor ruled by
intensity as well, so that ups another one for Sony.

Now here is a question, if Sony provides higher levels of brightness (for a
given resolution) does this not imply that the luminous "dynamic" range is
greater as well? If so would this not be an important consideration in telecine

>From Vistek, a European monitor maufacturer, I learned that the 9 to 20" tubes
are selected from tubes normally destined for the computer industry,
interesting. Noticed how difficult it is these days to get those cute little
high quality monitors?
The reason behind this would be that there is no global demand for 10" computer
monitors anymore and thus no way to skim the cream off for high quality video
applications. Of course Sony are not affected since they mfg own tubes and now
beeing alone in that particular nische......

Back on track, the discussion is on the choice and performance of the telecine
suite reference monitor. Based on this you have a choice of deciding to try to
attain a local "house reference" or something more complex, a " global
reference". SMPTE and EBU are great to hold on to as wise men have put some hard
thinking into the recomendations.They may lead to the impression that if you set
your monitors to recomendend brightness and colour temperature, you now have a
uniform level on which to argue the world with. This is not the case.

Having the ambition to create and maintain a house reference, even if it means
setting up your own standards is wise. The important thing to remember is to
stay with what you have been doing as all previous work is referenced to those
settings. This of course means to stay with the same hardware. At some point in
time the hardware must be replaced and this is a problem as it turns out that
many manufacturers have then "improved" on their product. I talked with a non US
facility who had this problem when replacing their Barco's with recent models
and the tube was a different one with detectable colorimetric differences.
SMPTE versus EBU phosphors. The only practical thing these two have in common is
the setting of the color temperature reference.
Illuminant D65 is thus not a colorimetric reference as it tells nothing about
what colours it is made of. Therefor it is only usable to set white balance at
an arbitrary brightness.  When plotting the phosphors on a CIE diagram one can
see that they share aprox. 90% of the colour space. It is a bit like drawing two
triangles on top of each other with one rotated some 10 degrees, imagine the
resultant areas as beeing the part where one monitor can not reproduce what is
seen on the other. Moreover since the shared area do not have colorimetric
commonality except only on the 6502 deg. Kelvin reference spot, grading on one
SMPTE "C" monitor  for display on an EBU type is hazardous. So for PAL country
releases an EBU monitor should be used.  Digital  colour space conversion can
only overcome this to a certain extent, the non-confoming areas between the
colour spaces are inaccessible. 

Abney law states (simplified) that when primaries are additively mixed (as they
are in a monitor) the brightness is a sum of the individual levels. Hence, the
Sony with the Trinitron principle produce greater brightness and saturation. In
my mind when it comes to television sets nothing beats the Sony's, but is that
what you desire in your TK suite?
Just one more thing. Many of the TKgrading  rooms I have visited throughout my
years are equipped  with worklights using fluorescent tubes producing illuminant
D65 light. Any other light source present, be it halogen or incandescent light
of any kind will throw that carefully set reference out of balance. Even passive
surfaces like non-neutral density walls will reflect an unbalanced spectra back
into the room. Too strong lights from signal monitors can be an issue.

There are more worms in the can but I have to get back to work.

Mike Reichel 100316,1467 at compuserve.com

If you would prefer to receive this mailing list as a digest every 
three days, send a message to "telecine-digest-request at xyzoom.alegria.com"
with the Subject: subscribe.