On Thu, 8 Nov 2001, phil at rephil.org wrote:

> There may be a little significance, but the color is just a by-product
> if that is the case.
> 
> Many cheap (consumer electronics) PCB's are green, because they use a
> cheaper board, and only one sided thru-holes.  Often times, blue
> boards were a sign of a better board (I forget the material) with a
> better (epoxy?) finish and dual sided / plated thru holes.  [1] Also,
> I recall seeing blue typically on multilayer PCBs, i.e., 3 or 4
> circuit layers sandwiched together, and in a really heavy RF
> application (like a GHz processor) might even have an internal ground
> plane.  I don't recall seeing green for "real" PCBs.

 Okay.  I asked a question, you gave a valid answer.  Works for me. :)

     Jima