I agree, D50 and D55, are Daylight White Balance references, so is D65…
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good link, definitely a confusing subject, thanks for taking the time to try and gain a better understanding
quoting from your link (in italics ):
Setting your white balance will allow your camera to identify the color of pure white.
Our eyes have a decent ability to correct white balance
Without setting your white balance, your true white colors may appear unnaturally blue’ish, orange’ish or even green’ish
white balancing identifies what is white in your footage
The two color temperatures you’ll hear most often discussed are outdoor lighting which is often ballparked at 5600K and indoor (tungsten) lighting which is generally ballparked at 3200K. These are the two numbers you’ll hear over and over again. Higher color temperatures (over 5000K) are considered “cool” (i.e. Blue’ish). Lower color temperatures (under 5000K) are considered “warm” (i.e. orange’ish).
Therefore if you are shooting indoors under tungsten lighting at 3200K you will set your white balance for indoor shooting at this color temperature. In this case, your camera will correct your camera’s settings to ensure that white appears white. Your camera will either have an indoor 3200K auto option (even the most basic camera’s have this option) or you can choose to set it manually. That is all you need to do to set your white balance. Once you’ve set your white balance you don’t need to change it after each shot unless the color of light changes.
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Same info as quoted], in my words:
in this image the white balance that shows the optisolis as white, is 6500k (D65)

at 6500k (D65) white balance, the 3000k 219c (sm303) looks very orange.
at 6500k white balance, a piece of white paper illuminated by the optisolis, will look white in a photo, and the same piece of white printer paper illuminated by the 3000k 219c will look orange
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So, what if we are taking photos of a piece of white printer paper, using the 3000k 219c as the only light source, and we want the photo to show the paper looking white? Then we would have to set the white balance reference for the camera, to 3000k.
The 3000k LED, can make a piece of white printer paper look white in a photo, IF the white balance reference point of the camera is set to 3000k also
And the paper illuminated by a 3000k source, can look white to our brain also,
IF our brain spends at least 30 minutes exposed to Only the light of the 3000k source.
Our brain can adjust its own white balance so that we see the piece of white paper look white, when illuminated by a 3000k source.