Update on the spectacular sheet with “missing black” 4c/8c Josephine Bruce rose.

30/5/08

Geoff Rickards has submitted the following informative and incisive update for members.

Readers of Royal Lines might recall my comments on the premier item of the May 2008 RPSNZ sale – lot 892: “1979 4c on 8c Rose definitive, sheet [100] missing black colour completely in 2 columns [20 stamps], part (missing) in adj’t 2 columns. ….”

(see RPSNZ web page for colour illustration).

Detailed studies of the sheet of these rotogravure printed stamps have revealed a systematic pattern of defects covering all 100 stamps of the sheet, as follows.

(i) In the stamps of columns 1 & 2 the otherwise lighter shadows (of the outer parts of petals and leaves) have failed to print, while inner shadows are weakly printed.

(ii) In the stamps of columns 3 & 4 all shadows (greys and black) are completely unprinted.

(iii) Column 5 stamps have shadows that are darker than normal, with unusual blotches and streaks of black in many places and numerous flaws where black has apparently “lifted-off” either the red (of the petals) or the green (of the leaves). Similar “lift-off” flaws are found, in decreasing extent and frequency, in the stamps of columns 6-10.

Throughout the sheet, stamps within a given column are essentially identical in the above three respects, while showing very sharp, vertical boundaries between columns 2 & 3 on the one hand, and columns 4 & 5 on the other.

The “usual” explanations of missing colours in gravure printed stamps in general do not seem to be adequate for this particular case. These explanations are [reasons for their exclusion in this case in brackets] -

* Paper fold: [no paper crease; right hand portion of printer’s information missing rather than misplaced]

* Temporary interruption of ink supply: [sharp boundary effects, as indicated above]

* Momentary lifting of impression roller from paper: [gravure printing would transfer ink from etched cells equally across all shades of grey-black]

* Extraneous matter overlying paper: as for interruption of ink supply.

Rather that any of the above explanations being applicable, it is suggested that the error(s) probably arose from a temporary STOP being put on the printing process (for whatever reason). The stop occurred between the printing of the stamps of columns 2 & 3 (the sheet being printed horizontally from left to right). The consequence of the stop was partial or full drying of ink on the black printing cylinder, as follows. (i) During the slow-down immediately prior to the stop, ink destined for the stamps of columns 1 and 2 had became partially dried, more particularly in shallow gravure cells, resulting in defective printing of the shadows, especially the lighter shadows, of these stamps. (ii) During the period of the stop itself, ink in gravure cells lying between the print-point and the doctor blade dried completely. This ink had been destined, before the stop, for the stamps of columns 3 & 4. On resumption of printing, these stamps, therefore, received no black ink. (iii) Also during the stop, ink on the cylinder downside of the doctor blade dried partially so that, on resumption of printing, doctor blade function and ink transfer to the stamps of columns 5-10 was disturbed.

A complete, fully illustrated account of these observations and explanations will be published in the September issue of the N.Z. Stamp Collector.

Ideally, a sheet of stamps such as the above should remain intact. However, any breaking-up (if it were to occur) should be horizontal, rather than vertical, so as to preserve the full story of the origin on its stamps.