Protecting coloured copper.
If you are colouring your copper, by flame, or paint, or patina, the colours can change drastically if you try to put a protective coat on them. Pam East published a great video on YouTube about this a few years ago, "Perfect Patina with Pam East: Liver of Sulfur Tips and Tricks". ( She does a comparison of protectants at the end of the video). I needed a finish that wouldn't change the colours, and after a LOT of trial and error, I found Soluvar spray. In this video I use the matt finish. It's not perfect, by any means, but it's the best I found.