Why Does DCP need XYZ conversion?

Hello. I wonder this topic. I could not find any information about that topic. Why does not run DCP systems with RGB? Why do we need RGB to XYZ conversion? What is reason? Thanks already.

The basic Idea (in lame terms) is to:

a) preserve the material for the future
b) have a system that is unequivocally understood around the world.

If you think about your RGB, my first question will be:

Which color space your RGB is coded for? Rec709? P3DCI? sRGB? BT1886? based on this info I will have to setup the projector.

If we stick on P3DCI, when the next generation of projector will be out what do we do then? we will project the P3DCI on the new rec2020 (Or whatever will be)? No it will look wrong. Will we have two different masters? Too prone to error and too costly. Then two year after we have to start all again for the same reason.

A XYZ master coded will achieve the dual purpose of being display agnostic and future proof because XYZ encompass any projector color space that we can see (and manufacture) in the future. an XYZ master will look the same as it is now projected ten year from now in any part of the world.

(is your avatar the old "doom" guy???)

Thank you very much Walter. I supposed it but I could not be sure. You gave really important informations to me.

And Yes. Its old "Doom" guy with Power Eternity mode