PCB circuit boards can be made in any color you like.
The actual circuit board is not green, but a printed material called solder mask is green. It is a layer of solder-resistant resin. It is printed on the parts of the board that should not collect solder. It prevents solder bridges from forming between IC pins. In the old eras of wave soldering, it can prevent the board from picking up large amounts of unwanted solder.
Green is a pigment in the resin formula. Green is specially selected as an auxiliary means for manual inspection of PCB boards. Although most checks are done automatically, manual checks are still sometimes required. Since it’s standard, the performance of green solder masks is usually slightly higher than other colors. It might be a factor in dense designs, but for most PCBs, green is just the default. Unless you order something else, you get it.
The green you see is the solder mask color. It is located on the topmost layer of the component(to prevent shorts, soldering errors, etc.). There doesn’t seem to be a clear consensus on why most solder masks are green. However, here are some theories:
• Green is the color of the raw resin. It is melted in the early stages of PCB manufacturing to form the solder mask.
• Green comes from some military standard or military test.
• Green is the best background color to contrast with white silkscreen text on the PCB surface under different environmental conditions.
However, it is no longer limited to green, and most PCB manufacturers like to advertise that they can produce boards with all different colors of solder masks.
