looking at a HEX colour picker:
RED: 255,0,0 to WHITE: 255,255,255 as long as the 2nd and 3rd hex digits are the same and go up in regular intervals then it will be a RED getting lighter till it gets to white
BLUE: 0,0,255 to WHITE: 255,255,255 as long as 1st and 2nd hex digits are the same...