kelvin scale

I am looking at accurate way to find the correct Kelvin Number for my Pentax camera.

Without buying an expensive meter.
I have searched online , but if someone can link to a resource , I will be thankful.
Alternatively a good book , I am considering Tony book (From Tony and Chelsea).

This is what becomes of not taking a course in the earlier stages of my Dslt journey. Too many gaps.

Regards

If its still relevant there is a whole thread of it on here from 10 years ago https://www.pentaxforums.com/forums/6-pentax-dslr-discussion/78873-color-tempera...

rob dean. .......Cheers for the link.