/vr/ - Retro Games

>>3927981
The big colorful thing represents every color the average human eye can see.
Y is luminance and X is wavelength. (Roughly, it's a bit more nuanced than that.)
It's curved because the cones that compose the human eye don't have a linear response curve, meaning each cone is responsive to a range of frequencies, and that sensitivity isn't linear. See pic related.

Each triangle represents all the colors possible within their respective color space. (the colors inside the triangle)
This is called a gamut.

Most all modern displays (meaning made after 1994) use the sRGB standard, or color standards which are closely related, like SMPTE-C or Rec. 709.
it wasn't until 2015 that displays capable of displaying the wider Rec. 2020 colorspace were manufactured, and even then they only cover 98% of the Rec. 2020 gamut.
Furthermore, Rec, 2020 is relegated to 4k "UHDTV" displays.

There are lots of way to represent color, and not all colors are possible withing all color spaces.
Just a few common examples would be YUV, RGB, CMYK, HSV, and YCbCr.
RGB to CMYK is a pretty common concern, since computer monitors output colors through RGB, but printers use CMYK, so graphic design artists have to take care that the colors they use fall within the CMYK gamut, otherwise the final printed product won't print color accurate to how it was designed.