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Strange Coloration Issue

R

Red Monster

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Hello all. I am currently working on a REDone shoot in Pennsylvania, and we were shooting a night scene with a small fire. In the hot center of the fire, we had a strange color shift: the fire was visibly orange/white but appeared to be violet/pink on all of our monitors. We are shooting 4K, 2:1, 24fps and we are monitoring on a Panasonic 17" LCD that has been properly set up. Any ideas why we are seeing such strange aberrations, would be very helpful....

Thanks!

Brian
 
we noticed that we can stop down the camera to achieve the proper coloration, but doing that meant that our scene was WAY too underexposed, and it is generally unacceptable that we can't have a fire overexposed in a nighttime camping scene. if it's a situation where our fire will look like a pink neon light because the camera can't handle an extremely bright source like a fire, then it seems to me that this is a pretty serious dynamic range issue with the RedONE.
 
can you post a pic?
if this behaves like pink sun, this means the pink you find in your image equals to max/absolute white.
This means you can expose your scene as needed and then just substitute pink with white in post.
if not, this is somethin' different?
 
I get this on every camera on every monitor. It doesn't have to be overexposed. A correctly exposed red car looks pink.
It's pretty ridiculous, and a fix or explanation is really necessary.
Redalert results are fine - color snaps back to where it should be, when adjustments are made and default is selected (I believe this is what must be done - I can't quite remember - haven't been doing transcoding lately).
Open the R3D in Redalert and have a play.
 
one thing I experienced, especially with the color RED:
- the IR filter becomes very important. Didn't find a way to correct it otherwise for the SDI-output and the look was also ok then on the raw-files. The filter can have an awesome effect. Were you shooting tungsten ? Fire is not only warm, naturally it has a high IR content..
I made this experience with tungsten.
 
markp said:
I get this on every camera on every monitor. It doesn't have to be overexposed. A correctly exposed red car looks pink.
It's pretty ridiculous, and a fix or explanation is really necessary.
Click to expand...

interesting! in what "VIEW" mode did you get this monitor output?
RAW? Red Space? Rec 709? every one of those?
 
At what color temp is the camera set? I just had a client email me with some stills taken from the proxies of a night scene where all of the streetlights turned bright solid cyan as they overexposed. When I put the .R3Ds into Red Alert it turned out that the DP had set the color temp to 2113 K. Not sure why he arrived at that number, but that's where it was set. When I slid the color temp up just a little bit, everything looked normal again.
 
Hot fires will have purple/pink/violet embers due to infrared(IR) bleeding into the sensor - a 'hot mirror' filter will remove it straight away (not in post, however, that's a secondary grading issue).
 
parisrem said:
… it turned out that the DP had set the color temp to 2113 K. Not sure why he arrived at that number, but that's where it was set.
Click to expand...

They may have touched the auto-white in RA.
 
All electronic detectors are very sensitive to IR. So when shooting a scene where there is a bright heat source i.e fire, molten metal, sunsets & sunrises etc
one can expect issues.

A few years ago I was filming a sunrise with a video camera and noticed that the sun was:
1. A completely different colour in camera.
2. The focus point/plane had shifted dramatically because of the IR overwhelming the visible light focus point/plane leaving me with the choice of do I want a sharp sun or sharp foreground (both were at infinity!)

Some tests later I established that extra (sometimes substantial) IR blocking was required to capture such scene "accurately".

JohnF
 
We also have a pink tint on red surfaces. It's pink in the evf, lcd and in the panasonic monitor. Its not a kelvin, view or exposure issue. When I see it in RA all is ok without me changing the metadata settings, the reds are red not pink. This is an anoying issue for the DP, he cant trust the evf, lcd or the monitor on set. Hope someone can explain why this is.

-Andreas
DIT
 
schneider IR filter

schneider IR filter

Red has a high sensitivity to light in the IR spectrum, and though the IR light is not visible to the human eye, it can result in odd color shifts and prevent a camera’s imagers from capturing true blacks. As digital cinematographers use multi-stop neutral-density (ND) filters to allow them to open their lens iris for more depth of field, IR light begins to dominate light from the visible spectrum, making its pollution all the more apparent. Or in your case low
light levels with the fire emmiting high IR.
Schneider, a world leader in precision optics for nearly a century, developed its TRU-CUT IR-750 filter to remove the IR spectrum from the light path, resulting in more vibrant colors and true blacks from both CCD and CMOS imagers. The TRU-CUT IR filter blocks the IR light mere nanometers from the visible spectrum, eliminating IR pollution from the image.
 
Thank you all for your help! It sounds to me that the IR filter is now an absolute necessity for this camera...I hate that the answer is ever "fix it in post", as most DPs cringe at that response. Time to switch from a 4-stage matte box to a 6-stage matte box, I suppose, since the damn IR filter will have to be around constantly.

Brian

p.s. Sorry for the lack of responses from me...I've been in the middle of nowhere without internet...
 
Valde said:
interesting! in what "VIEW" mode did you get this monitor output?
RAW? Red Space? Rec 709? every one of those?
Click to expand...

I have found the REC 709 mode to be over saturated in the magenta area.
I find RAW to a little bit closer to reality. The fact that everthing is fine
in Red Alert or Red Cine would lead me to believe it's a monitoring output issue.
 
I agree with you, seacliffe301, the magenta is definitely very much over the top in REC709...especially on skin tones around the mouth, cheeks, and fingers, where there is a lot of blood flow close to the surface of the skin. Strange, eh? It makes sense, but it couldn't be any more annoying. What I find is that clients rarely have a good enough 'eye' to notice. For my DP, I like to switch back and forth between RAW and REC709 on set...boy would it be nice to send REC709 out of the HD-SDI (for clients) and monitor RAW with the Red LCD...Pipe dreams? I hope not...
 
P.S. I ordered a hot mirror filter from our camera house for my current job, which we'll be using in a bright exterior with the potential for some 'pink-ing' that may occur with bright sunlight. Does anyone know how many stops this may suck away?
 
I once had this issue... it turned out that redcine had altered my "tint" parameters.
 
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