Every so often the question comes up: "How well does FilmStar perform with large numbers of layers?" Frankly, it's hard to know unless there's something to compare with.

We stumbled upon a recent US patent containing a recipe for a 180 layer edge filter. With all the extravagant claims, we assumed this was the best possible design (two other thin film design programs were referenced in the patent) and frankly doubted it could be improved. Just for fun, we entered the design into FilmStar. Using 401 optimization targets, FilmStar improved the design in about two minutes on a 3 GHz computer.

We thought you'd be interested in seeing the results; we added an original design evolved from the well-known highpass construction (.5H 1L .5H)^N. The web graphic you see was created and saved in PNG format directly by FilmStar, but that's another issue.