3c Washington Grill Question (Scott 88, E Grill)

Hi all,
I'm trying to determine the grill on my 3c Washington. It has 14 columns of points. However, the rows have me confused. The top row and the bottom row consist of rectangular impressions, not square-ish impressions like the rest of the grill. This drawing shows what I mean:



So, when counting the rows, do I count the "half rows" too? There are 16 full rows in the grill in addition to the two half rows. The actual dimension of the grill, including the top and bottom rows, is 11x14mm.

Here is the back of the stamp. The scan is deceptive. Those diamond-shaped light areas are actually the spaces between points in a column. The top and bottom rows can be seen clearly.



I'd like to hear your opinions, E grill or Z grill, or fake?
Regards, Robert

Robert,

My understanding is that you count the grill points. That would exclude those horizontal ridges at top and bottom of the grill in the image you posted.

Here is a "negative" of your stamp that more clearly shows the points.



By my count, this is an E grill showing 14 by 16 points down.

There is additional information on grills in this Siegel Auction Galleries article that Russ has previously posted on the forum. http://siegelauctions.com/enc/pdf/1867.pdf

Steve

Follow-up:

In my research of this grill, I discovered the E grill and Z grill are almost identical in size. The distinguishing characteristic is the orientation of the ridge on the points. The E grill has a vertical ridge, while the Z grill has a horizontal ridge. The diagram shows what I mean:



I examined my stamp under a microscope; the points have vertical ridges, so that makes it an E grill, therefore, Scott 88 (it is the very thin paper variety).

Steve, thanks for pointing me to the Siegel Auction Galleries article.

Cheers, Robert

Further follow-up:

Currently, there is a spirited discussion of Z grills at the Virtual Stamp Club. According to one expert, besides the horizontal orientation of the points, there must be 18 horizontal rows also. His reasoning is a strongly impressed E grill may exhibit some peaks that mimic the Z grill orientation.

Regards, Robert