Removing light effect in S4 Studio Warehouse?

I made an override cc file of a simple wall decal item found in the paintings category, and unfortunately it turns out it has the effect of a lamp (probably smaller light radius, but I wish there was no light at all).

I found some options for lighting effects in the Sims Studio Warehouse. But those codes say nothing to me, and I wonder if there is a way to turn the light effect off?