Hi all,
what Alex said is probably a good option.
i chatted to a friend of mine who's close to all the technical
camera-related stuff.
his answers in short form:
1) wrong cabling would most likely result in wrong colors
2) check which camera firmware and recorder was used
3) check which ArriRaw Converter version was used, 2.3 being the newest
- since today, actually (that link you already got from Alex)
last but not least, post it on the official Arri forum. there's a chance
of having someone from Arri reply to it
http://forum.arridigital.com/forum/
cheers,
Holger
Aélis Héraud wrote:
Hi Howard, hi Alex
Thanks for the tips guys, we tried the TVIscale, that seems to help a
bit more than bluring the red channel, we're still looking for a
lossless solution but the TVIscale could be our best option so far.
We're waiting for some original Arriraw footages in order to test the
Arriraw converter.
I'll give you feedback if we find a way to fix the problem.
Thanks again,
Aélis
On 6/29/2012 11:02 AM, Howard Jones wrote:
I had something similar once - where a cable had been plugged in
wrong. Basically both R and B were 1/2 res blown up to full size. ie
like proxies.
The quick solution was to rescale to 1/2 res at impulse then resize
with a better filter. It worked to a fashion.
I didn't try TVIscale but that might be worth a go.
Assuming that is the issue of course. The blue has been rubbish on a
number of shots for me too.
Howard
------------------------------------------------------------------------
*From:* Aélis Héraud <[email protected]>
*To:* [email protected]
*Sent:* Friday, 29 June 2012, 15:26
*Subject:* [Nuke-users] Artefact Issues with Greenscreen Alexa
(ArriRaw)
-- Okay, I had some trouble sending this mail last night so I
hope you'll receive it now. Sorry for duplicates copies. --
Hi folks, I'd like to ask you something.
We have to deal with some greenscreens in Alexa and I know some
people have had some trouble with it. Overall the greenscreens
are pretty good and we're able to get a good result, but we
noticed something on the data and I'd like to have your say on
this matter.
We noticed some artefacts in the Red and Blue channels,
especially on the thinner blond hairs.
The plates are in 2880x1620, it was recorded in ArriRaw (via
T-Link) and then converted in DPX (Colorspace AlexaV3LogC) so
it's pretty much the best quality we can have, there's no
compression.
RGBsamplesAlexaArriRaw.png
As you can see the RGB seems pretty much ok and the green channel
is good, but the red one has some pixels in staircase and I won't
even talk about the blue one. The last picture is a first key.
After some investigations we're pretty sure it has something to
do with the debayering process. It's maybe due to the algorithm,
the interpolation between pixels isn't very good in the red and
blue channel. I don't know exactly but that's the only
explanation we could come up with so far.
My question is : Is there a way to fix it in Nuke without
altering the data (the good one) or are we stuck with that ? Any
idea ?
I tried to split the channels and to put a blur at 1 on the Red
one and it seemed to help a bit at first but eventually we can
feel the softness and we lose the thinner hairs, which I'd like
to avoid. I'd keep that as my last option.
Our other option would be to ask the company who did the
debayering but I'd like to find another way.
Thanks for the help
Aelis
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--
Holger Hummel - [email protected]
Celluloid Visual Effects, Paul-Lincke-Ufer 39/40, 10999 Berlin
phone +49 (0)30 / 54 735 220 - [email protected]
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