Still messing with the photo etched windows. Blackening photo etch with a chemical agent can get messy. I went to Hobby Lobby and purchased a set of Scripto magic markers in colors, the oil based ones. I have been using those on the window frames and on the photo etch. The markers adhere well to both plastic and photo etch. At $1.69, they are much cheaper than paint or blackening agent, and as long as you keep them capped, the pigment doesn't settle and the paint doesn't dry out. They don't spill either. But you must use the oil based markers. The tips come in two or three different sizes, and they are only good for small areas. They would never do for a hull!