Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

FYI,

For most of these dry film resists, I've found that a 15 second
exposure in direct sunlight is about right. Rainy or otherwise cloudy
days ruin the parade, of course.

Allow exposed film to 'age' for at least 10 minutes; then develop with
1/2 TSP sodium carbonate (Arm & Hammer Super Washing Soda) in 8oz of
warm water. Strip with 2 TBS sodium carbonate in 8oz hot water.

I'm getting .010 traces with excellent definition using this
method...your results may require some experimentation from there.

Hope that's helpful, Jim