Hi Paul; I went to the machine manufacturer's website (Z Corp: https://www.zcorp.com/en/Products/3D-Printers/spage.aspx) and found lots of data on the material properties - everything but density! Try emailing Z Corp and asking them what the density of ZP150 is: https://www.zcorp.com/en/forms/Ask%20a%20Pre-Sale%20Question/ form.aspx? Hey Shapeways reps: does Shapeways use the new material or are you still using ZP130 or ZP131? The colours look much brighter in ZP150. Scott