Why are PCB boards mostly green?
1. Green solder resist ink is the oldest and most popular with low cost.
2. In general, the entire electronic board-level products have to go through several processes in the yellow room, the visual effects of green is the best. In SMT welding, these processes are required to optically calibrate the alignment, a green background makes the instrument identify the effect better.

3. Common are red, yellow, green and blue. As a result of the process, the test of many lines relies on workers to check (of course, now flying probe test is popular). It is a very tiring work, the green color is less harmful than others.
4. Blue and black boards are mixed with cobalt and carbon, aong with a certain conductivity, so there is som risks of short circuit. Green PCB is more environmentally friendly and will not release toxic gases in high temperature environment.

5. Since 2007, people began to notice the color of the PCB board. Mainly because many first-tier manufacturers of high-end boards are using green color, so people all think that the green board is high-end.
Statement: This post is only the personal view of the author and does not represent the opinions of ALLPCB.com.