In looking at the image in the link to Artius, I copied the image and enlarged it. Tough to tell from the image for sure, but it appears to me that there is a clear foot at the base of that bottle, visible on the leading edge........ If so, it would indicate that there was some use of clear with the ground color. Could also be an illusion in the image..... or a reflection......
I am not pushing for an attribution one way or another, just making some observations relative to information provided here....
Craig