I place all my vray lights on their own layer and turn the layer off when I don't need it. But come render time, i turn the layer on and i'm good to go.

A similar request from 2016 https://sketchucation.com/forums/viewtopic.php?f=15&t=64668&hilit=size+component

@cleeman10 said: Hi guys. I just downloaded a bunch of vismat files. When I open them in V-ray, the material looks different from the preview jpg included with the vismat file. When I open the vismat and see the preview IN v-ray (not the preview jpg) it looks different and much worse from what it should look like. It is a different color from the diffuse bitmap texture entirely, the reflection is out of whack... I don't know what's going on. It's like this for every vismat I just downloaded from vismats.com I've attached some pictures to explain my situation. Thanks in advance!!! It's a colour space issue. Go to the diffuse slot of the material and click on bitmap. Change the colour space from screenspace to linear space or vice versa. I personally, would prefer to go with custom gamma and specify what I'd like the material to look like instead. Usually a value of 0.5 works for me.