There are artists who have strong opinions about particular shades of particular colours. They don't just say 'that looks like green paint to me.' They say 'there is a world of difference between this green and that green. I can hardly believe that any visually sensitive individual could fail to acknowledge the importance of the distinction.' If you are dealing now with someone whose preferences are quite so precise, you may have no option other than to humour them. But do you really need to make life so hard for yourself?