Australia Opening Of Sydney Harbor Bridge Guide Line?

A question. This is Scott 130, ACSC 146. Recess Printing. I can see a Guide Dot in my block of 4, but I can't figure out this extra line, visible on two different copies. Is this what is referred to as a Perforation Guide Line that, according to ACSC, is opposite the space between the 4th and 5th horizontal rows?

Guide Dot


Guide Lines (?) in two different stamps

Can you post the relevant piece regarding "perforation guide line"

I had the 2d recess as, plate numbers, perforation guide pips, added by hand.
No reference to a guide line.

Would not a perforation guide line, be severed by the perforation process?

Interesting facts:
The Liner under the bridge, offered significance to the size of the Bridge.

Here she is.......

Here are the pertinent sections from my ACSC:



So, I don't really see anything that discusses these vertical lines. Ideas?

No, I am at a loss.
Does not look perpendicular, so hand drawn line, or just an EFO

The sheets took 20 presses of the treadle to do one sheet of perforations
the recess was done on dampened paper, so there was paper shrinkage.
ergo, 4 sheets at a time were perforated, going by your examples, they look quite accurate.

Stages
Printing
Sheets dampened
Flat Bed Press
Inked
Printed
Left to dry (shrinkage)

Gummed

Grouped by plate numbers
Perforated
Guillotined
Checked
Distributed

This is troubling (Collyer and Peck)
unless I am misunderstanding

Stages of the 320 on should be

Printing
Guillotined (4 sheets of 80) (If done after perforation, the sheets may slew under pressure)
Gummed
Perforated

Interesting fact.
Construction of the Sydney Harbour Bridge had not finished when the design of the stamp began,
so Harrison had to work with drawings, models and advice from Bridge designers.

RMS Orford and the coat hanger.

When the bridge was built, grey was the only available colour in a large enough quantity to paint the entire span of the bridge. 272,000 litres of paint were required to give the bridge its initial paint.

Plate 1 – Dot and guide line on bottom left of selvedge.
Plate 2 – Two dots and guide line on top right of selvedge.

The 5/- also has a plate dot, this stamp is hard to find. I currently do not have plates 3 & 4 of the 2d, though I will have them soon.

Thank you for the examples, but I'm still wondering if my two versions of a vertical line/scratch are anything significant. It's odd that I would find two exact copies in my limited collection. Hmm.

Brief piece about Dorman Long of Middlesbrough, which built the bridge

https://en.wikipedia.org/wiki/Dorman_Long

Floortrader, I wished someone from Australia would comment on that line. Personally I believe it looks just like an engravers' slip, but I have no knowledge of Australian stamps.


Peter