5c Washington Coil - Forgery?

Found this in a dealer stock that I purchased a while ago and not sure if it is fake or real. It was labeled as a #458
Perforations are 10 - Single Line Wmk. - Design Size is 20mm x 22.5mm
The pencil marks between the perforations on the back of the stamps has me wondering why?
Also - The design size is too large for a 458?
Any thoughts or input - good or bad - would be greatly appreciated.
Thanks!
Harry

Congratulations, it's a #458 line strip. Can't quite tell if the leftmost stamp has gumsoaked or just dirty perfs.



It's not. The sizes that Scott and others give is nominal; that is, there is a range and the measurement is not exact to the thousandth of a mm. Paper is wetted before printing which stretches it, and different degrees of stretching plus shrinkage when dry can occur.

Obviously, rotary coils cannot be made from imperf sheet stamps; there are no imperfs. Lines can be drawn to forge line pairs and the end perfs can be reperfed. The line looks correct from here as do the end perfs.



As for the pencil lines, note how the perfs wander slightly (which is okay here). My two guesses is that either someone was trying to prove to themselves that the perfs were not perfectly in line as seen from the front, or that someone was trying to figure out how to fold along the perfs and break out the line pair and not end up with short perfs on either side of the break (and gave up).

looks nice, almost impossible to fake

For those who insist that perf holes should not line up in parallel rows or columns in genuine coils, take a look at this. By my eye, it looks like (from left) the 1st, 2nd, 3rd and 5th lines of perfs line up at top and bottom. They probably don't really when using a microscope. Plus side by side comparison of each perf in each column shows different amounts of "wander" from an absolute straight line of perfs. Just saying that we have to look at the complete picture.

Nice line strip. I'd keep it intact to avoid the problem of separating the line pair. Speaking of dealers, this is how a lot of coils were stored by dealers to fit in (I think) size #3-1/2 or #4 glassines. But you might have found that out already.

Rotary press coil perforator pins were attached to bars attached in rows around a cylinder. Perforations were applied a row at a time at right angles to web, ten coils wide. Rotary press coil perforations are aligned between rows. Also, hole elongation, pressure ridges and pulled fibers occur in the direction of the coil, unlike flat plate line perforated stamps where the action is in the direction of the perforation row.