Matching paint colours?

V-Ray V-Ray for 3ds Max General
1

I am often asked to use a specific colour by clients, for example Resene Concrete - Hex #D2D1CD, RGB 210 209 205 | Swatch | Resene Paints

Tyipcally what I do is grab the swatch image, load it as a texture, apply an curve on the the texture node and pull it down a bit at the high end, and call it a day.
However, this is basically eyeballing.

Does anyone know any more accurate methods to reproduce base colour in V-ray (reflectance and such notwithstanding)

2

you have rgb values provided, just put them inside vraycolor map and apply gamma correction if you are working in linear color space. reflection and fine structure of this paint is a different story, you can eyeball it, or you could send sample to chaosgroup and they can scan it and prepare vrayscan material which is accurate. Second option will cost you some time and money, but if you really need something 100% accurate, thats the way to go.