Note the difference in color between this old commodore board and this newer board. It might seem like lighting, but after looking at my own collection of scrap boards, the older ones tend to have a much darker color than the new. I thought it might be aging on the mask, but all the old ones essentially have the same color, so I thought it unlikely.
Does anyone know the reason for this color change?
Is it a change in board material, masking chemicals, etc?
Best Answer
It is superficial, the color is determined by the place of manufacture. Earlier on a darker green was the most used and often the only color available at most board houses. After a while, there were other colors available but often at an added cost. Today you can even order dark green or light green from some manufacturers with no additional cost. Most of the boards I order look the same color as the commodore board.
The color does not change unless maybe the PCB has been exposed to UV (sunlight) or a chemical and I would expect that would make the color lighter not darker. Exposing the PCB to heat can make the solder mask darker, but usually this is not uniform across the PCB.