Lysaght ORB Galvanized Tinned Sheets

Sheets with the reversed or mirrored trademark

The claim that they are seconds

Spennermann in his analysis of another building where sheets were found with marks mirrored asserts this is not from stacking while wet, because there is no smudging, so he then assumes it was an intentional way of marking "seconds", or faulty sheets, which were sold at a lower price. This needs much more elaboration which is not provided in the report.

Having my own examples and need-to-know, I have to dispute this with the following analysis.

Evidence of secondary transfer

As context, these sheets are hot dipped galvanized as indicated by the pronounced spangle of the zinc coating. Also, the trademark indicates the sheets were made in England, otherwise the mark would include the word "AUSTRALIA". According to Spennermann (Techniques in Historic Preservation: Recording Corrugated Iron) this suggests the sheets are circa 1880 to 1924 at the latest, from which I conclude they are the original sheets from the 1879 schoolhouse build.

It is clear from image 1 below (from the roof of this schoolhouse) that it is a secondary transfer because:

  1. only the outlines of the rubber stamped primary have been transferred.
  2. they are clearly smudged either through movement of one sheet relative to the other or the ink has spread/bled as the sheets have been pressed together as the weight of the stack increased.

According to Spennermann (Techniques in Historic Preservation: Recording Corrugated Iron, page 4), the brand was stamped before corrugation, i.e. while the sheets are still flat. Typically, the sheets would have been manually handled but guides would be used to ease handling, the result of which would have been that sheets were constrained horizontally then allowed to settled on top of the previous sheet vertically, doing so gently as the air between them compressed before it could fully escape.

1. Lysaght ORB Galvanized Tinned roof sheets.

This is not a reversed photo. Note the smudging at the bottom and outlining, indicating that this is a secondary transfer off a partially dry positive.

For comparison, look at these images of positive prints from Spennermann's report:

As a result of the stamping process the outlines of the letters and graphic elements are typically thicker because excess ink is squeezed out from between the die of the stamp and the steel sheet, to accumulate at the edges and therefore taking longer to dry. To corroborate this to some extent, images of positive transfers show areas where the outlines are darker than the interiors. This, of course, is dependent on the control of the amount of ink deposited on the stamp.

More questions

Other questions that need to be answered:

  • Would the mill really use a reverse print to denote seconds?

Deliberately printing reverse images on sheets would necessitate ensuring that similar images never occurred accidently. There is no advantage at all to be gained by marking seconds this way.

From about the 1960s we know Lysaght positively marked sheets as "seconds". I don't know if they also included the brand trademark on those sheets, the Lysaght Referee is not explicit on that.

  • How would this reverse printing have been achieved?

It would require a dedicated stamp applied at a stage before the end of the process, i.e. while sheets are still flat. There is no evidence of faulty galvanizing or cutting in the schoolhouse sheets. Corrugation was applied after the point where sheets would have been sorted as seconds, so why not simply sell the "seconds" as flat sheet? Why add cost by not removing them immediately from the line? Faulty corrugation of sheets already marked as firsts would have either to be ignored or the sheets discarded completely. It would have been far more efficient to have devised a method of marking seconds that could be applied at the end of the process.

  • Why do we see this only on sheets with this trademark?

How were, for example, the QUEENS HEAD flat sheet seconds marked? Any recorded examples?

  • Would factory "seconds" have been exported?

Production and transportation costs would be identical for both firsts and seconds so it would make no sense for the product with the lowest margin at point-of-sale to travel the furthest distance to get to that point. It would be more profitable to sell seconds at the factory gate.

There was also a documented period during which Lysaght were making a small loss on exported sheets in order to establish market share and so exporting "firsts" would be essential to compete in what was considered a significant market.

Really, there would have been far simpler and less problematic methods available at the time to deal with "seconds", including sending them back through the galvanizing process again.


The premise that there must be smudging to indicate secondary transfer by stacking is unsubstantiated in the Spennermann report.

The handling would be designed to minimise this because to smudge the negative is to smudge the positive.

Nevertheless, there is evidence of smudging, even in the Spennermann report itself. The report's Fig 58 shows a reverse image that is very clearly smudged and displays the same outlining as image 1 above, which is indicative of secondary transfer. Figs 231 and 232 of the report are two images of the same mark and clearly show a partial imprint or smudge to the right of the orb symbol that isn't part of the mark - possibly an initial contact before the sheet came to it's settled position. And then there is my image 1, which also shows smudging.

Impossible to prove either way

If image 1 is secondary transfer from the sheet above in the stack then logically there would be a positive image on the other side of each sheet, but proving that is almost impossible. Any sheets left unpainted would have lost the exposed positive long ago and if painted have been buried. I'm not about to attempt to peel layers of paint off to find out, not yet. There is another possibility: in each stack there should be at least one sheet that does not have the reverse image, i.e. the top and/or bottom sheet. If the production line worked in bundles of stack numbers, either 96 or 98 depending on gauge thickness, then the schoolhouse roof might have one if any such sheets in it. That is not really worth looking for. Without an example of a single sheet with both positive and negative images on it, it does not prove the point either way.

Reputation at stake

The contractor Samuel Cox ran the Post Office in town and was therefore a well known member of this small community. He was very keen for this schoolhouse to be a show case in gaining further work. This was also a government funded project.

Proof in the longevity

For sheets that are supposed to be seconds they have lasted a very long time, and still have some decades of use before they will need to be replaced.