About colour correction and oscilloscopes

I have used X-Rite to set the color temperature of monitors at work, but I would hate to try to set gamma with it. The benefit of using a computer monitor for this purpose is that the computer can read the values returned by the sensor and adjust parameters such as gamma. What’s amazing is that for a couple of hundred bucks you can have a setup for calibrating monitors that would have been prohibitively expensive in days gone by.

I can understand the desire for a Conrac because it’s what you’re used to from back in the day, but times and the technology have changed and you may as well get with the modern stuff.

Personally, I use an LCD TV set rather than a monitor designed as a computer monitor. It has a brightness control which works like a brightness control is supposed to, so I have finer control over the black levels. I created a custom test pattern which has a proper pluge so I can set black levels according to SMPTE like we used to do on CRT monitors. If I go through the menu settings I can select the RF input and watch over-the-air TV signals.


One data point you should know is that it’s a de-facto standard to set the white patch to 100 nits (100 cd/m2).

Thanks for the tip.

It’s been about two decades now since I was keeping up with video monitor calibration professional literature; at that time, any LCD was scoffed at as “uncalibratable, really” because the red, blue and green are not the same nanometer points on the photon spectrum as the “standard” CRT phosphors. “It is like comparing pineapples to durians” they would moan. “Just because you have six of each doesn’t mean you have the same fruit basket.”


Back in the day, the recalibration sensor unit “knew where it was” on the screen by time-synchronizing the photo-diode spikes with the video horizontal traces. An expensive and finicky piece of equipment.
But out of the box, the Conrac was good enough for most work; it was factory calibrated, and so was within all but the tightest specs when you never broke the seals on the potentiometers.

ebay currently has a new, never used, one for $700…

People are making YouTube videos that look great on an iPhone, and look like crap when you watch them on the big flatscreen in the comfort of your livingroom via FireStick.
Nice to know what it will look like on a real TV before publishing it.

Thanks for bringing me up to date with all this info, @chris319.

(My son is showing me how to do animations with a stack of index cards by flipping the corner of the stack. Why back in the day, we…
…and the audio over the string between the papercups…)

The problem is usually the other way around. iPhones are stunningly accurate to the DCI-P3 and sRGB standards. Proper transforms from BT.709 will look equally good. YouTube videos look awful on consumer televisions because it’s the uncalibrated TVs that have terrible color. That’s why every TV on display at Walmart has a different color picture even though they’re all playing the same video. But every iPhone in Walmart looks identical. They’re just that good. A properly calibrated studio monitor or decent home TV will of course not have this problem.

iPhone accuracy is plotted here if curious:
DisplayMate Reference Colors and iPhone 11 Pro Max Absolute Color Accuracy Plots

Also, the RGB color primaries were changed yet again for BT.2020, so I’m not sure the Conrac or its phosphors are a great long-term investment… :grin:

Good to know.

And yet the on-air signal on all those Walmart TVs looks good enough to sell a TV, which means that video engineers at the big networks know what color balance to use to accommodate all of those out-of-calibration TVs reasonably well.

When I was working in the music industry in Nashville, every studio had very expensive perfect sound reproduction speakers by Klipsh or Harrison or a few others. But the most successful sound engineers and producers would bring their own speakers, typically four-inch RadioShacks mounted in coffee cans. Most top-40 listening was done in cars using the speakers Ford or Chevy put in stock, so if you wanted to go gold, your music had to sound good on those speakers, as well as on the top of the line.

Ah, the color primaries war. The old defenders must all be dead now; they never would have let that happen.

I’ve put my custom test pattern on YouTube. The colors have been turned to mincemeat. I don’t know if the problem lies with YouTube or my browser. I’d have to download the file and check it.

Having been one of those video engineers, we set up the video to look good on what else? A Conrac CRT monitor! Then Ikegami and Sony monitors came in, all CRT. The Ike’s had a probe to set them up.

That said, I strongly discourage you from using a Conrac CRT for any kind of critical video work in 2021. It’s not worth pouring money down that rathole. Get yourself an LCD TV set and a proper calibration program and sensor.

That said, I own an RCA 77-DX, hardly state of the art. It sounds good but for me it’s more an objet d’art. We all have our indulgences.

Here is what I have. It allows me to set proper black levels.



(New third monitor candidate.)

The add is a bit unclear about the USB port; does the USB also act as a video input, or only the analog in and HDMI?

Not really for “critical work” as a video engineer would define it, more of a sanity-check.

The nature of my work is such that much of my potential audience are octogenarians watching on an ancient Magnavox with a grudgingly-added “digital box” under it, as well as their grandson’s “other” gamebox plugged into those funny colored connectors which lets them also see YouTube. I just want to know if my videos that look good on LCD look like crap on CRT.

Well, it’s your money. I hope the videos you make are 16:9. It’s the latest thing :slight_smile:

That TV set I linked to hooks up to my graphics card via an HDMI connection. Graphics card is an NVIDIA GeForce GTX 1050 Ti.

1920x1080 now.

Granny gets black bars at the top and bottom.

You are right, unless I find a steal of a deal, my money is better spent on the LG.

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