Question Regarding Historical Use Of Scissors To Detach Stamps

I'm researching perforations and have seen a number of forum posts that mention the use of scissors at the post offices to detach stamps - I have a couple of questions:

1) in the 20th Century why was that necessary?

2) does anyone know if scissor-detatched stamps leave any special markings on the perforations? I ask in order to see if there may be a way of distinguishing between guillotine cut stamps and those separated by scissors.

I believe the need to use scissors related to stamps issued imperforate in sheets. I'm not sure when perforating machines started to come into use, but it seems to me that once stamps began to be issued with perforations there would have been little need to continue using scissors to separate them.

Dale

Simply for the reason the 20th Century saw the issuance of imperforate stamps. The US Farley Special Issues for example. As to other imperforate stamps, there were reasons, most production and demand related, for imperforate material.

Even now in the 21st Century I go to a post office and receive stamps separated by scissors by the clerk so the edges of the stamps are not damaged. For example the US 5297 Statue of Freedom $5 is produced with a strip of non-stamp dividing paper between the stamps. Cutting along that paper produces a single with no damage to the stamp itself.


A single:





From a multiple:



Seek out writings on the subject of stamp separation by John Hotchner.
His exhibit on the matter may be available as well. Perhaps someone will add a link.

Perhaps more likely that, when perforated stamps were introduced, staff in offices, rather than post offices, may still have found it easier to cut than tear, particularly where a small number of perforation holes were used - eg US stamps, if I remember rightly.

Thank you! I appreciate the replies.
My area is Holyland/Mandate so my points of reference may not be familiar to some of you. Attached is an example of the phenomenon I'm researching: what are those [possible] marks on the tips of the horizontal perforations? Are those cutting marks or even just natural marks from normal detachment?

Opinion:
They look normal separated stamps to me.
A few flat spots on the Orange, but just EFO
The guage on these stamps gave a regular and consistant separation
according to my collection, rare to see long teeth or pulled perforations.

Scissor cut perforations are generally immediately recognisable (and ugly) Once seen, never forgotten.

Scissor cut stamps (Pre perforate era)
Moldavia (Romania) "Cap de Bour"
and Great Britain or US Cartoon.

Thanks Rod! Having read your reaction I took a closer look at each of the teeth and indeed close-up it's possible to see that they are not cropped but rather shorn as they would be from a stamp sheet.

Gum Side,
one will oft make acquaintance with cut perforations, in either "Mission" lots, or new collectors cutting stamps from covers.

For some strange notion, that one has to cut to the nearest hairline of the teeth for best results, and in practice, failing.