Shots of Louis (Louis Hansel)
We have all been in this boat before: the video or graphics content doesn’t look way on the screen that we thought it would. Whether that’s with the naked eye, when compared to a computer screen or reference monitor, or through the lens of a broadcast camera, chances are all of us have had a head-scratching moment of wondering why the blues don’t look blue.
With more churches than ever before now being concerned about how their set and backdrops look on camera, thanks to the pandemic-induced increase of online streaming, it’s a good time to review some of the possible reasons why colors may not be translating as expected.
... chances are all of us have had a head-scratching moment of wondering why the blues don’t look blue.
While there is no “one size fits all” approach, there are generally several things that techs can try in their effort to get a more natural representation, or at least come closer to meeting the expectations of what something should look like in the room.
First, let’s set aside the camera perspective for a moment, since there are so many variables that can be wrapped up in that. Let’s start simply with the problem that my video content (whether graphics or videos) doesn’t look the same on screen as I was expecting.
What to consider first
The best way to start is simply by checking each step of the signal path to see if there may be a variable that is unknowingly causing the issue.
Some computers have output settings that have subtle changes in color profiles. These will make small adjustments to the colors of the video output to make them warmer or cooler. This is an easy way to start the troubleshooting process, especially if the content looks correct on the computer screen/monitor and is clearly different by the time it arrives at the display device, whether a TV, projector, or LED wall.
Another easy option would be to check similar settings on the display TV or projector. Most all of them nowadays come with varying display profiles, each designed to adjust the image quality based on what type of content is primarily running through it.
There could be a “game” or “cinema” mode that has been activated. Or, for a projector, it could be running on an “economy” mode with decreased output brightness (to help a lamp last longer), and that lower brightness could cause the colors to look inaccurate.
If you’re sending to an LED wall and the colors are off, there are a variety of potential variables or issues just there with the wall and its peripherals. There are settings in the processor that could be adjusted, the panels themselves may need to be color calibrated, or, if it’s a lower-cost and lower-quality wall, the LEDs themselves may be unable to accurately reflect the colors, and there may be some limitations to the quality of the final image you’ll see.
If you’re not able to work directly with the LED manufacturer on solving issues you need help with, there may be an integrator or vendor in your area who has the expertise (and, in some cases, the right tools) to help make some adjustments with the wall itself.
Sometimes, though, the source and the display are both set where they need to be, but there's something in the signal path that’s introducing a discoloration. This is where I need to be able to go step-by-step through the process to check every device and conversion to see what may be introducing the issue.
How would this work? I need to find a monitor I can use for reference, and by starting at the source, work my way through the signal path and test a direct output off of every device in line.
Hopefully by testing each piece of the video signal’s path, I can narrow down where the coloration problem is coming from.
The computer signal converts from HDMI to SDI before hitting the switcher? Can I loop out of that converter to see how the image on my monitor compares to the source computer? Perhaps the converter may have an issue (like overheating or a loose connection) that could be impacting the color appearance.
Can I take a monitor output directly off of my switcher to test the signal’s accuracy before it goes to the display destination? Some switchers may unknowingly have a “proc amp” or desaturation setting activated that could be impacting the output quality.
Hopefully by testing each piece of the video signal’s path, I can narrow down where the coloration problem is coming from.
If, though, I’m not able to clearly identify where to fix the issue, I could then consider introducing a LUT box to the equation.
These small devices, shaped and priced like a signal DA or converter, allow me the ability to make in-line color adjustments to my source. So, I wouldn’t have to change a projector or TV’s global settings, but I could just make adjustments to one particular source and its signal flow.
Now, if I’m seeing color accuracy issues on camera, as compared to the naked eye, that’s where a whole new realm of variables comes into play.
[LUT boxes], shaped and priced like a signal DA or converter, allow me the ability to make in-line color adjustments to my source.
The most impactful starting point would be to examine the white balance/color temp settings for my camera and the lighting fixtures I’m using.
In most rooms without cameras, techs tend to use a warmer color profile on their front lighting to ensure that the skin tones of their talent look warmer and more natural in person. This will make Caucasian skin appear more orange or pink, but at least it gives the appearance of warmth. Measured on the Kelvin scale, these fixtures may be in the 2k range for color temperature.
On the flip side, most standard broadcast environments that use cameras tend to use fixtures with a cooler color temperature (perhaps 5k or higher), which will give skin tones a more gray or blue feel in person.
Once a color temperature has been established with the lighting fixtures, the camera settings for white balance must be matched to those lights so that the camera is able to make internal adjustments to know how cool (blue-ish) or warm (orange-ish) a white image will be.
That’s where the color changing can come into place.
By warming up or cooling down its interpretation of “white” in the color temperature settings, I’m making adjustments in the camera so that it sees skin tones naturally, based on my lighting. The flip side is that it’s also adjusting the appearance of all other colors in the shot.
So, that’s how I end up with purple looking blue and gray looking tan … as I adjust camera settings so that the capture or broadcast looks more color-accurate, I can actually also make that shot look noticeably different from how it looks in-person to the naked eye.
Viewing audience or live attendees?
This is where it’s important to make the distinction as to which audience is more important: is it most critical that things look natural in the room, or is it more important that things look great on camera? It may just come down to which audience is larger.
At our ministry, we are willing to make some sacrifices in the room and cater to the broadcast, since the size of the audience that watches on video dwarfs the size of those who see the service in person. Does that mean we’re unconcerned with how it looks in person? Absolutely not. But we know we will end up leaning one way at the end of the day, but we’ll still do our best to get things as close as possible, knowing that how the content looks on camera is ultimately the most important factor.
At our ministry, we are willing to make some sacrifices in the room and cater to the broadcast, since the size of the audience that watches on video dwarfs the size of those who see the service in person.
Some cameras also have a “black balance” setting that can deepen the darker colors on screen so that the blacks don’t feel washed out or muted.
While camera white/black balance and front wash settings have a big impact, the color temperature of the other devices on stage can have a bearing in how the stage appears on camera, as well.
LED-based lighting fixtures tend to natively put off a cooler color temperature than conventional lamp-based fixtures. So, if you’re using older lekos for front wash, yet lighting your set with newer LED fixtures, there’s going to be a natural color temperature difference that will become even more evident when you white balance to the warmer front wash.
You can help offset this disparity by adding gel to either (or both) sets of fixtures; CTB (color temperature blue) gel will help cool off your front wash, and CTO (color temperature orange) gel will help warm up your LEDs. This can bring both fixture types closer to a center, so when you white balance, the color disparity won’t be as great.
The thickness or depth of the blue/orange in the gel ranges from quarter to full, depending on how much of either color you’d need to add.
If you’re using an LED wall behind talent that is lit with conventional fixtures, you’ll see the same type of color gap on camera due to color temperature. The warmer front wash will be starkly different than the cooler LED panels, and there will again be notable color differences when seeing it with your naked eye as opposed to seeing it through a lens.
Again, you will have to ask yourself which audience more greatly requires color accuracy: those in the room or those on the other side of the lens.
No color problem is completely unsolvable. Sometimes, though, it’s necessary to realize that it may not be possible to get a 100% accuracy match, but there are still ways to dramatically close the gap. Understanding where the difference may be coming from in my signal chain is the critical first step in the process so I can know my options and where I can try to mitigate the disparity.
That’s how the light bulb clicks on--and I can solve my color conundrum.
