IMAG color correction on screen

lbou

New Member
This is more of a camera/video question but I figure someone here knows the answer.

Often IMAG (image magnification) will have inaccurate color of scenic elements and or graphics on screen that the camera happens to capture.
My question is, is there a best practice for matching color across all elements (lighting, camera and projection)

Currently we white balance the camera as well as color correct across different lighting fixture types and depending on the projector we will play with didn't color temperatures

Occasionally we nail it and everything looks good but I'm not sure what magic is happening to achieve the continuity.

Hope this makes sense.
Thanks for any suggestions
 
The Phrase of the Day is "color calibration". I'd start with calibrating the projector/LED wall first, and then working down stream to the camera.

The biggest issue is that the human eye does not perceive colors in the same way as most video cameras render them. This may require shading at the switcher (Black Magic Designs) or CCU (everybody else, mostly), or storing a LUT in the camera CCU. Good luck.
 
You don't mention what your display is, and it's probably the most critical element.

Note, too, that some displays have bad color shifts off-angle.
 
The process (trick) I learned from a smart experienced video engineer:
  1. Make sure your engineering monitor is calibrated
  2. "chip" the cameras to a chip chart/grey card under show key lighting conditions
    (he also was experienced enough to know how to tweak it so skin tones looked great, based on the vectorscope)
  3. send smpte color bars to the imag screens
  4. point cameras at imag screens, zoom to just fill the frame
  5. color the imag screens so the bars look correct on the scopes
This results in the imag matching as close as the technology allows.
Good luck
 
The process (trick) I learned from a smart experienced video engineer:
  1. Make sure your engineering monitor is calibrated
  2. "chip" the cameras to a chip chart/grey card under show key lighting conditions
    (he also was experienced enough to know how to tweak it so skin tones looked great, based on the vectorscope)
  3. send smpte color bars to the imag screens
  4. point cameras at imag screens, zoom to just fill the frame
  5. color the imag screens so the bars look correct on the scopes
This results in the imag matching as close as the technology allows.
Good luck
Thank you! 3 thru 5 is what I've been missing. Excellent
 
I forgot to add... no matter what, your backgrounds/scenic elements won't match if they are lit differently.
If you keylight at 4400K, but light the backgrounds at 6000k, the backgrounds will have too much blue. Likewise if you light the backgrounds to 3600k they will have too much yellow.
Finally, "colorspace" is a thing. Most cameras and imag screens are shooting and or displaying in the "rec 709" colorspace.
If you look at the chart on the right of the wiki link here: Wikipedia Rec 709 You will see that the cameras and screens only cover a small portion of the spectrum (and even the chart is misrepresented because your computer is probably Rec 709 and cant actually show the colors from outside the triangle.

Good luck
 
Yeah I've experienced this spectrum issue. The issue for me is mostly about matching color across all elements. To reiterate, say I have a screen over head on stage and it has a companies logo on it. If I take a wide shot it will capture the over head screen and often the colors look different on the outboard screens.
To your original steps
(as mentioned by earlier responses) would you start out by matching the projector color temp to the stagewash ?
Say lee 203, 4300?
And when you say in step 5 I think, to color the screens, are you taking about coloring the camera or the projector?
 
Another thing is if I'm lowering the temps of the projectors this will affect all of the corporate colors in the content and potentially look different than printed materials. It all starts to get circular in my mind.
 
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Another thing is if I'm lowering the temps of the projectors this will affect all of the corporate colors in the content and potentially look different than printed materials. It all starts to get circular in my mind.
Color the projector to adjust the bars to what looks correct on the engineering monitor/ vectorscope/waveform monitor.

Yes you can get into a spiral of doom chasing color matches, which is why production design decisions before the first load in are important. If the client art is optimized for viewing on a computer it is probably Rec 709 D65. The D65 means it uses 6500k as the white reference, so you'll need to key your presenters at 6500 and light scenic elements with 6500k for everything to "match".. now you may drop your key light to 5000K or even 4700K and the presenter will appear a little warm on IMAG, but an acceptable level.
The flip side is if you want to shoot the keys at 4700k, you may have to have client art re-rendered with the different color point so it looks correct. It is a tough nut to crack if everyone isn't on the same page to start. This is a difference on big budget corporate events. When there is a half million dollar budget, some of that can pay for a camera and content match in the shop with re-render costs budgeted, etc. Doesn't always happen but not uncommon.
 
Color the projector to adjust the bars to what looks correct on the engineering monitor/ vectorscope/waveform monitor.

Yes you can get into a spiral of doom chasing color matches, which is why production design decisions before the first load in are important. If the client art is optimized for viewing on a computer it is probably Rec 709 D65. The D65 means it uses 6500k as the white reference, so you'll need to key your presenters at 6500 and light scenic elements with 6500k for everything to "match".. now you may drop your key light to 5000K or even 4700K and the presenter will appear a little warm on IMAG, but an acceptable level.
The flip side is if you want to shoot the keys at 4700k, you may have to have client art re-rendered with the different color point so it looks correct. It is a tough nut to crack if everyone isn't on the same page to start. This is a difference on big budget corporate events. When there is a half million dollar budget, some of that can pay for a camera and content match in the shop with re-render costs budgeted, etc. Doesn't always happen but not uncommon.
Awesome info. This last bit really helped me understand what's going on.
 
Awesome info. This last bit really helped me understand what's going on.
I'm glad Ronnie responded to your thread. He deals with this on a daily basis but I'm mostly audio dept. It all gets wonky when the LD makes color temp decisions. You're chasing your tail if the physical logo art on the set and on the site graphics was rendered for 5K, is lit by a variety of 3200 to 6500K sources, and then we add the variables of video. Client then complains that none of the artwork looks right but especially on screen. Been there, watched that...

Companies spend lots of money establishing brands and chosen colors are a part of that. What is frustrating is chasing this 'tail' when the only persons who notice a difference are the people paid to see those differences. Sometimes there is an "Emporer's clothes" group think, where as the size of the critique party enlarges, so does the confirmation of the problem du jour. Then, others who were left out of that party find other issues to put on the list of Things To Address before rehearsal.
 

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