Hexachrome is a way of printing that uses six different colors instead of the usual four. The four colors we normally use to print things are cyan, magenta, yellow, and black. These are often abbreviated as CMYK. Hexachrome adds two more colors to the mix: orange and green.
By using all six colors, printers can create a wider range of colors than they could with just CMYK alone. Imagine if you only had four crayons to color with, but then someone gave you two more colors, orange and green. Suddenly, you could color so many more things and make them look more realistic!
Hexachrome is especially useful for printing things like photographs, where having a wide range of colors is very important. However, not all printers are capable of using hexachrome, and it can be more expensive than printing with just CMYK. But for certain high-quality printing projects, hexachrome can be a great choice to make things look as good as possible.