banknoteguy
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Posts: 291
What I collect: 19th Century US, High denomination US (> $1), 19th century covers US, Indian Feudatory States and most recently I acquired a BigBlue [with about 5,000 stamps] and pristine pages.
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Post by banknoteguy on Sept 19, 2021 14:11:59 GMT
Sn.342 $1 Washington 1909 Flat Plate
I was looking at my two examples and noticed one was smaller. After measuring I found it was .5mm difference in the vertical dimension of the design. Images below.
Does anyone know why this happens? I know rotary printing can stretch a design but flat plate?
Rule added. I also added tiny white lines extended from the design top of each stamp to the rule. The stamp on the left is 21.75mm and the one on the right is 21.25mm.
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WERT
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What I collect: Canada and Provinces
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Post by WERT on Sept 19, 2021 14:23:39 GMT
Hi banknoteguy It is hard to measure when stamps are not picture taken together. Anyways, go to this web site..You will find everything you need her.
Robert
STAMP SMARTER
stampsmarter.org/learning/Home_USID.html
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banknoteguy
Member
Posts: 291
What I collect: 19th Century US, High denomination US (> $1), 19th century covers US, Indian Feudatory States and most recently I acquired a BigBlue [with about 5,000 stamps] and pristine pages.
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Post by banknoteguy on Sept 19, 2021 14:30:57 GMT
All these items were scanned together - the two stamps and the rule. I used GIMP to line them up but no changes to the sizes. So, the difference is real.
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banknoteguy
Member
Posts: 291
What I collect: 19th Century US, High denomination US (> $1), 19th century covers US, Indian Feudatory States and most recently I acquired a BigBlue [with about 5,000 stamps] and pristine pages.
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Post by banknoteguy on Sept 19, 2021 14:32:25 GMT
I know about Stampsmarter but I could not find any answer to this question.
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brightonpete
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On a hike at Goodrich-Loomis
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Post by brightonpete on Sept 19, 2021 14:49:03 GMT
That picture looks like two different scans to me. I'd scan both at the same time at 300 DPI, and use Stamp Analyser to get exact data from each. Available for both Mac's & PC's. No Linux version, sorry WERT !
Stamp Analyser is the lazy man's way of getting all the data out of a stamp lickity-split! I like it!
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banknoteguy
Member
Posts: 291
What I collect: 19th Century US, High denomination US (> $1), 19th century covers US, Indian Feudatory States and most recently I acquired a BigBlue [with about 5,000 stamps] and pristine pages.
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Post by banknoteguy on Sept 19, 2021 15:00:58 GMT
It may look like two different scans but it is not. One scan at 1200dpi simultaneously of all three items done this morning. GIMP used to align the pieces. I can see exactly what you see in the image in hand.
I know .5mm is not much of a difference and it may be that different sheets printed at different times had different drying rates. Perhaps that explains the difference.
I just thought there might be a W/F expert who might know the answer.
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banknoteguy
Member
Posts: 291
What I collect: 19th Century US, High denomination US (> $1), 19th century covers US, Indian Feudatory States and most recently I acquired a BigBlue [with about 5,000 stamps] and pristine pages.
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Post by banknoteguy on Sept 19, 2021 15:22:47 GMT
I can see I have caused some confusion. My normal process to compare stamps closely is to scan them together (with GIMP) and then use GIMP to extract parts of the scanned image and use GIMP alignment tools. All while keeping exactly the same pixels, so the comparison is exact.
This process may be not be familiar to TSF members. Sorry.
So just to show these stamps (which are the same variety supposedly) really do exhibit real differences, here are two more images.
The first is the same two stamps, in a mount aligned by hand and a ruler. No processing at all other than cropping just the two stamps for the image. I think you can clearly see the difference in design size.
Here is an 2nd image -- the only difference is I used GIMP to add a grid overlay. Other wise an identical image.
You can see the design is larger by almost the whole border size.
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WERT
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Posts: 1,062
What I collect: Canada and Provinces
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Post by WERT on Sept 19, 2021 15:22:53 GMT
brightonpete..There are lot a of programs for Linux for accurate measuring...banknoteguy uses some.. banknoteguy..You have to scan BOTH stamps at the same time to be able to measure accurately...Using GIMP or other programs. Remember this point brightonpete..MAC computers use the Linux kernel...Windows don't. you can do accurate measuring banknoteguy..Then measure the other with a scan of BOTH stamps. Just my opinion working with software programs over the years. Stay safe,,, Robert
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banknoteguy
Member
Posts: 291
What I collect: 19th Century US, High denomination US (> $1), 19th century covers US, Indian Feudatory States and most recently I acquired a BigBlue [with about 5,000 stamps] and pristine pages.
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Post by banknoteguy on Sept 19, 2021 15:29:17 GMT
Robert (WERT) said,
I completely agree with you -- if you want to compare images (of anything really), they should be scanned together. And everything I have posted this morning has been scanned together.
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angore
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What I collect: WW, focus on British Empire
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Post by angore on Sept 19, 2021 17:28:21 GMT
Rotary and flat plate press Wash Franks do vary in image size since the paper wraps around the press using the rotary method. I did not look at specifics.
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renden
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What I collect: World W collector with ++ interests in BNA (Canada etc) and USA
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Post by renden on Sept 19, 2021 18:27:04 GMT
Rotary and flat plate press Wash Franks do vary in image size sinve the paper wraps around the press using the rotary method. I did not look at specifics. I liked this article and it is a 101 explanation of the 2 printing process discussed here stormthecastle.com/stamp-collecting/articles/flat-plate-or-rotary-plate-stamps.htmRené btw even if I was raised in a printing shop (my late dad's newspaper and printing businesses + store) I really never studied printing but did some of my own (on the less complicated presses) as a young Teen !! |
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WERT
Departed
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What I collect: Canada and Provinces
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Post by WERT on Sept 19, 2021 18:55:40 GMT
Hey Rene In high school 4 years and 1 year on the job..I used printing press machines..Here are a few i used and also had a darkroom to etch aluminum plates..etc..etc.
Robert
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renden
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Posts: 8,737
What I collect: World W collector with ++ interests in BNA (Canada etc) and USA
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Post by renden on Sept 19, 2021 20:15:11 GMT
Hey Rene In high school 4 years and 1 year on the job..I used printing press machines..Here are a few i used and also had a darkroom to etch aluminum plates..etc..etc.
Robert
Robert (WERT) ....looks very familiar - Dad had more sophisticated machines (never understood them but who cares - I never became a printer LOL !!) René |
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khj
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Post by khj on Sept 19, 2021 22:09:06 GMT
I defer to those with printing experience. But I can only point out:
1. wet paper varied in moisture content, so shrinkage after printing will vary
2. shrinkage may vary in different direction, depending slightly on any preferred "orientation" of the paper pulp or grain direction
3. therefore dimensions given in Scott are approximate average, not exact
I would say 1/4mm variation can be found without too much difficulty for wet printed stamps; 1/2mm variation is a nice conversation piece (not that common, you almost have to come upon 2 opposite extremes).
As an example of #2, you might even find the dimensions smaller in one direction, but oddly enough, wider in the perpendicular direction! That's also a nice conversation piece. I don't have background in printing, but always assumed that was a result of differences in grain direction? Try slicing/overlaying your original scan and see if you might have such an example (i.e. one stamp taller but unexpectedly also narrower).
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banknoteguy
Member
Posts: 291
What I collect: 19th Century US, High denomination US (> $1), 19th century covers US, Indian Feudatory States and most recently I acquired a BigBlue [with about 5,000 stamps] and pristine pages.
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Post by banknoteguy on Sept 20, 2021 0:03:33 GMT
khj said,
I think you have hit on an important point. I did check the width. In this case they are identical.
But I have not tried to determine grain direction. I would agree 1/4mm might be expected but 1/2mm seems extreme.
I will examine these two stamps further and see if I can determine a grain direction. One might be vertical and the other horizontal.
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banknoteguy
Member
Posts: 291
What I collect: 19th Century US, High denomination US (> $1), 19th century covers US, Indian Feudatory States and most recently I acquired a BigBlue [with about 5,000 stamps] and pristine pages.
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Post by banknoteguy on Sept 20, 2021 15:21:39 GMT
Sn.342 $1 Washington 1909 Flat Plate -- Paper
The two examples I have seem to be on different paper. Paper thickness is pretty close at about 2.75mils for each. But they look quite a bit different. One had at least the perfs on the left side trimmed, and quite likely the perfs on the right side also. The surface of this paper is rougher also.
The other is on a smoother whiter paper. Even though the image below does not look whiter because I darkened it.
It appears to me that the trimmed example has a vertical or possible diagonal grain pattern. The whiter example appears to have a horizontal grain pattern. I'm not 100% sure of this but see the images below. This may explain the vertical design size difference (~.5mm).
Trimmed example:
Whiter example:
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