bcuddy
Member 
Posts: 123 
What I collect: United States, famous people
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Post by bcuddy on May 2, 2021 21:12:02 GMT
I'm having a hard time distinguishing between US flat plate printing, rotary printing and offset printing. Specifically looking at early 20th century Washingtons. Someone showed me a trick to cut the corners off a flat plate printed stamp and use that as a guide to tell the difference between flat and rotary and for the most part, I can make that work.
But what about offset? Is the image on the stamp the same size as a flat plate? Someone told me to look for specks of ink on the reverse side to distinguish offset, but is this always (or almost always) the case?
Any advice would be great. Thanks for your help. I'm going cross-eyed over here.
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tomiseksj
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Woodbridge, Virginia, USA
Posts: 6,269
What I collect: Worldwide stamps/covers, Cinderellas, Ohio Prepaid Sales Tax Receipts, U.S. WWII Ration ephemera
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Post by tomiseksj on May 2, 2021 21:55:50 GMT
bcuddy, Check out the info posted on Stamp Smarter regarding the printing methods for the Washington-Franklins. Offset printed stamps will be smooth, as opposed to engraved ones that have texture (i.e. raised ink). The offsets also appear dull and of lesser quality. As you mentioned, offsets will also generally have setoff on the backs because of having bee placed on previously-printed sheets on which the ink had not yet dried.
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tomiseksj
Moderator
Woodbridge, Virginia, USA
Posts: 6,269
What I collect: Worldwide stamps/covers, Cinderellas, Ohio Prepaid Sales Tax Receipts, U.S. WWII Ration ephemera
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Post by tomiseksj on May 2, 2021 22:25:55 GMT
Here is a side-by-side comparison of a flat plate printed stamp (Scott 462) and an offset (Scott 525) that shows the difference in print quality between the two methods.  |
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vikingeck
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Posts: 3,269
What I collect: Samoa, Tobacco theme, Mail in Wartime, anything odd and unusual!
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Post by vikingeck on Mar 16, 2023 21:30:42 GMT
I know nothing of these issues and really care even less, so not sure if this is the correct place for a posting on this 1c Washington that has me slightly confused. I hope some one can explain it apparently imperf on the left  |
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JeffS
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Posts: 2,610
What I collect: Oranges Philately, US Slogan Cancels, Cape of Good Hope Triangulars, and Texas poster stamps and cinderellas
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Post by JeffS on Mar 17, 2023 1:01:06 GMT
I suggest it is a stamp from a booklet pane of 6, from the imperforate left edge.
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Beryllium Guy
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Posts: 5,661
What I collect: Worldwide Stamps 1840-1930
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Post by Beryllium Guy on Mar 17, 2023 3:35:17 GMT
JeffS: Please permit me to add an image of a booklet pane to help illustrate your idea. Does this help? In Alex's ( vikingeck) example, it does show part of the adjacent stamp to the left, but that would just indicate poor cutting of the pane, right? 
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JeffS
Member
Posts: 2,610
What I collect: Oranges Philately, US Slogan Cancels, Cape of Good Hope Triangulars, and Texas poster stamps and cinderellas
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Post by JeffS on Mar 17, 2023 4:25:47 GMT
As Alex stated that he knew nothing about these and cared even less, I kept my response minimal. (And I certainly didn’t want to mention that the loathed Scott US Specialized catalog shows the plate layouts for booklet stamp printing)  none the less, thank you for your booklet pane example. |
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Beryllium Guy
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Posts: 5,661
What I collect: Worldwide Stamps 1840-1930
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Post by Beryllium Guy on Mar 17, 2023 5:06:01 GMT
Thanks, JeffS . Well, knowing Alex ( vikingeck ) a wee bit, I would just say that he cared enough to post the image for us, so despite his disclaimer, I think that he is interested in knowing if anyone can answer his query. Let's see what we can come up with. I like your idea that this stamp comes from a booklet pane, which would certainly explain the lone straight edge at left. But what's troubling me is that the left edge does not actually appear to be parallel to the right. It looks crooked, because it doesn't follow the printed frame line of the stamp, which suggests to me that it may have been hand cut or that if it was machine cut, there was some sort of a problem. Any thoughts about that? |
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vikingeck
Member
Posts: 3,269
What I collect: Samoa, Tobacco theme, Mail in Wartime, anything odd and unusual!
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Post by vikingeck on Mar 17, 2023 8:26:01 GMT
Apologies if my post was a bit flippant. I just wondered if the left perf had been missed and this might have been part of an “ imperf between pair “ and if such was known?
So maybe just a miss cut booklet item?
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Post by gstamps on Mar 17, 2023 10:25:40 GMT
I did not understand the names of the printing methods used by American collectors.
I think the term "flat" can also be applied to engraving, lithography or typography.
Am I to understand that "flat plate printing" means only engraving?
In the Michel catalog, the printing methods are described much more logically (technical terms are difficult to translate and understand).
3 types of printing are described (with several subtypes) depending on where the ink is applied:
1. below the level of the printing surface
2. at the same level as the printing surface
3. above the level of the printing surface
The printing surfaces can be flat or cylindrical.
I don't understand why the surface type is used as the name of the print type.
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Post by gstamps on Mar 17, 2023 10:48:24 GMT
I found the English translation on the "stamporama" website stamporama |
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JeffS
Member
Posts: 2,610
What I collect: Oranges Philately, US Slogan Cancels, Cape of Good Hope Triangulars, and Texas poster stamps and cinderellas
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Post by JeffS on Mar 17, 2023 11:30:46 GMT
Beryllium Guy and vikingeck my understanding is the perforating process and the cutting of the panes were two separate processes thus miscues such as Alex’s can be expected. Chris, your pane is quite nice as it shows the line which visually separates the left pane from the right.
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JeffS
Member
Posts: 2,610
What I collect: Oranges Philately, US Slogan Cancels, Cape of Good Hope Triangulars, and Texas poster stamps and cinderellas
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Post by JeffS on Mar 17, 2023 11:39:57 GMT
gstamps flat plate refers to the printing process which involves printing from a flat printing plate as opposed to a press that uses a pair of metal plates which are bent into a semicircle shape, attached head to toe to complete a circle, thus a rotary press process. This is an oversimplification. It has been over 50 years since I studied these.
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Post by gstamps on Mar 17, 2023 12:05:15 GMT
JeffSThat's what I said too, the printing process does not help me to know the type of printing (typo, engraving, litho) When I have the stamps in front of me, I try to recognize the type of printing. When I see "flat plate print" I don't know what it is: typo, engraved, lytho?
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JeffS
Member
Posts: 2,610
What I collect: Oranges Philately, US Slogan Cancels, Cape of Good Hope Triangulars, and Texas poster stamps and cinderellas
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Post by JeffS on Mar 17, 2023 12:47:25 GMT
gstamps flat plate and rotary press simply define the mechanics of the printing. One must look deeper to find what you want.
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none the less, thank you for your booklet pane example.