Hi friends,

Today's question is more along the lines of "teach a man to fish" than "help me fish."

I'm using my Precision US Specialty Multi Gauge to help determine if the stamp I'm looking at is a flat plate print or rotary print. When I try and line up the guide, depending on how I position the guide, the stamp looks like it touches the bold line (or it doesn't). The guide says, "If either edge of the design touches or exceeds the heavy line, it was printing using the rotary press method. If it does not touch the heavy bar it is a flat plate issue." The image below is the same stamp—just positioned slightly differently.



How do I make identifying the stamp's true dimensions (and ultimately method of printing) less ambiguous? Am I somehow making an error in how I'm aligning the guide? Is there a better method of measuring?

Thanks in advance for your time.

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51Studebaker

Dialysis, damned if you do...dead if you don't
06 Aug 2017
09:38:24am

re: Rotary Press Identification Question

Trying to measure stamp designs in Washington Franklins is often a fools errand. First, the design measurements listed in most references are estimates. Second, between user error/bias and measuring tool markings, getting a good measurement is difficult.

Here is a link
http://www.stampsmarter.com/learning/Manuf_printingmethods.html which will help you understand the production differences.
Don

Edit: I would also add that US flat plate booklet pane stamps were printed on horizontal mesh (or grain) paper instead of the normal vertical mesh paper used for 400 subject sheet stamps. So if the stamp may be a booklet stamp (i.e. it has a straight edge) other dimensional considerations must be made. The mesh (grain) of a booklet stamp will result in a slightly wider and generally slightly shorter than a regular sheet stamp. This trips up a lot of hobbyists and makes them think they have a rare rotary press coil waste. The chances of finding a rotary press coil waste stamp is about the same as landing a date of a super model and spotting Bigfoot while out on the date.

Hobbyists need to consider ALL the variables (setoff, perfs, watermarks, etc.) and understand production processes of the Washington Franklin era to make a positive identification. And given the large number of fakes, forgeries, and altered Washington Franklins out there it is inevitable that the any stamp thought to be rare has to be submitted to the experts for certification.

 
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re: Rotary Press Identification Question

There is a nice write up in Scotts Specialized as well. Flat plate stamps measure 18-1/2 to 19mm wide X 22mm high. Rotary stamps measure either 19-1/2 to 20 mm wide OR 22-1/2 to 23mm high depending on orientation.

I have found that the easiest way for me is to find a known flat plate printing and cut the corners off. Even though my alignment is a little off you can see that the flat plate stamp with the cut corners is shorter than the Rotary press Scott 487 below it. Others will be noticeably wider.

 
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cdj1122

re: Rotary Press Identification Question

Many tricky Machins can be separated similarly since the distances from the value to either margin is a known amount. (Detailed in the Deegam Machin Handbook) Trimming the corner of a poor example and placing one atop another assists in the identification of the stamps. Often I glue or tape the test stamp to a thin ( 1/8th or 1/2 inch wide and three or four inches long) makes a simple tool that is easier to handle than a single stamp.
There are probably many other sets or series that can be differentiated the same way.
And example would be the George V definitives whose heights can be short, medium and large.
Making your own simple tools to hold and manipulate a stamp used as a standard can simplify and speed up working through a large pile of duplicates.

 
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