On the inside of my valences, I currently have bare hardboard. On most of my layout, you can't see it, but on the outside of the peninsula, you can peek through. So here's a question for anyone who's painted the inside of their valence. What colour would you use? I'm thinking of perhaps painting the entire inside of the valence a light sky blue, not just for cosmetic reasons, but perhaps to reflect a bit of diffused blue light into the shadows. I'm using LED strips placed facing straight down immediately behind the valence. I'd love to hear your thoughts.
I painted the inside of my valences white so the light is reflected. Most of my layout has white colored cabinets above it so it was just the color to go with. Below is a link to a post in my layout blog that has some photos showing this. https://palisadecanyonrr.blogspot.com/2016/12/more-options-for-led-layout-lighting.html
The light source itself will have an effect upon the final results. The color selected may need to be a semi-gloss, or gloss to reflect decently. The light blue idea might work. If not enough, probably white? Is there a way you can buy just a small sample can, and do a test?
