Bi-Metal Corrosion On Bicolor Plates ...

the inorganic ink compounds caused wear on cliches and many plates; as well as damage to perforator pins .

in england, Royal Mail moved to organic inks.

welcome to the forum Mack Strathdee!

Hi and

Could you show us what you are referring to on a stamp, please? I understand the ink wear on the clichés and plates, but the damage to the perforator pins has me mystified.

there's no need, because it's not correct.

Thank you.

Certain Colorblends could turn acidic and cause wear - yes

But the main wear comes from the repeated pressure, and cleaning of the plates/cliches

Some blends Would contain higher percentage of metals which would harden faster and require excessive cleaning,

I Can of course back this with evidense if required..

In keeping the topic on bicolored stamps, it seems the different minerals in the inks colors cause varying rates of wear. Your study of the Danish Bi Colors posted not long ago was very interesting. Did you find that frame and vignette plates wore at different rates?

It's quite evident that the lower and top rows wore down faster than the rest.
the evidense of this is that most commonly the lower row has been disgarded and the plate shifted downwards and a new row has been inserted in the top (or simply exchanged)

a newly discussed area is the spacing between the ovalband and the ovalline has recieved a re-engraving resulting in a new series of "ovalflaws" referred to as "free way" (wider spacing than normal).

my theory in the discussion was that this is caused by hardening paint getting stuck and thus causing the space to "fill" with paint and a cleaning to be needed - this was done with a sharp instrument, slightly wider than the space - causing the space to widen while cleaning.

and my suggestion was that these new kind of ovalflaws most commonly would have migrated from the bottom row to new positions in later printings.
they suddenly appear in printings with 10-20 more or less obvious flaws, and then disappear as clichés are thrown away - earlier printingscolors would, in my oppinion, have had a blend that either hardened fast, or a higher concentration of metallic minerals.

most disgarded this, and I invited them to prove me wrong - Lasse Nielsen (most regarded expert) took this work on and found there was indeed a link.


i'll show examples later this weekend.

the notion that ink compounds causes damage to perforator pins is, in addition to alot of other things you post on other forums, complete gibberish.

stamps are printed, and gummed before perforated. and would have had to be dry before this process as multiple sheets were perforated in one go.

so for this to hold any truth, the paint would have to act as an armor so perforator pins would break off in contact with it?

I do not mean any disrespect, but I disagree with most of the above. Long ago, back in the eighties tha USPS found that the tagging ink applied to their coil stamps was eroding the perforator pins excessively. Hence they started to introduce block tagging.
Later, with the introduction of modified inks the use of block tagging ceased. In the original taggant a metallic ingredient caused the erosion.

Peter

First an example of how the wear shows on stamps in the lower 10th row.. the same happens to stamps in the top row.

this stamp is a quite expressive, not all stamps are as apparent from the lower row, and on a few stamps you can't tell the bottom row apart from the rest.



the "smear" i'm referring to as "stuck down" paint is also evident on this stamp

here's a regular somewhat boring 8øre



here's one that has had it's "spacing" between the ovalband, and the oval line.



compare the spacing of the 2 stamps and it's rather obvious.
to me, it's quite likely that the re engraved oval would have been placed in the positions that either recieved the most pressure, or in a print where the paint contained a higher concentration of metallic minerals.

none taken, by long ago, 80's do you mean 1880's or 1980's?

Neither tagging nor the USPS did exist in the 1880's so I meant the 1990's.

Peter

but this thread is on bi coloured stamps from denmark 100 years before this the proces was completely different.

Sounds like you've 'met' the op somewhere else.
How often were the plates thoroughly cleaned of dried inks? A weekly cleaning? Sounds like the printer walked a fine line between ink buildup, and wear.

"Just regular somewhat boring 8 ore".
Beautiful stamps. Thank you for the illustration of ink cause plate wear.