Preparation Of The Steel Plate

Prior to the actual laying down of the designs from the transfer roll as described earlier, the steel printing plate must be prepared. Everything that is done to this plate will show up on the printed stamps and so has a bearing upon the stamps you collect. After the steel plate has been annealed and made ready to receive the transfers, the exact position of each design is indicated upon the plate by means of "guide dots" or very faintly scratched lines. Bearing in mind that the paper upon which the stamps will be printed is first moistened and so will shrink, perhaps unevenly, the craftsman lays out his plate by means of precision tools to allow a sufficient space between each stamp both horizontally and vertically. Sometimes he will allow a difference in the width between the rows of the stamps, as in the case of the first stamps issued in 1908. Here it was found that, owing to the excessive unevenness in paper shrinkage, there was considerable waste because the sheets of stamps did not pass through the perforating machines correctly.

Hence experiments were made by spacing the six outside vertical rows of each printing plate a full millimeter wider than the inside rows. Naturally such a difference in the spacing of the stamps was not lost on stamp collectors who promptly had a new variety for their collections. It must be admitted that, so far as the author knows, this is the only occasion that a difference in width of spacing between the rows of stamps was attempted on the printing plates.

Tools used for the preparation of a steel plate
Tools used for the preparation of a steel plate:
1. Graver. 2. Scraper. 3. Burnisher. 4. Etching point. 5. Liquid etching ground. 6. Acid. 7. Engraver's glass. 8. Original die. 9. Transfer roll. 10. Flat stamp plate with 400 transferred stamps. 11. Curved stamp plate.

Among our nineteenth-century stamps especially, it is possible to see the position dots and traces of the guide lines on the printed stamps. In fact, these are very helpful to those who attempt to "plate" certain issues. But it is not unusual to find them even on the most modern issues. After the plate has received all of its impressions, it receives other permanent markings. The plate number is set in on the margins as well as, sometimes, other indicia of the various phases of manufacture. Permanent guide lines are cut between the four panes of one hundred stamps each. At the extreme margin of each of these guide lines an arrow is cut to call particular attention to the line. These guide lines are provided to assist the cutting operator when he divides the sheets of four hundred stamps into panes of one hundred in which form stamps are sent out to the Post Office.

subject rotary  plate
The layout of a 400 subject rotary plate showing electric eye guides for the perforating machine in center and at left.
A plate block of four stamps
A plate block of four stamps.

For modern stamps, which are printed from rotary presses, special markings are provided on the margins of the sheet to guide the electric scanning mechanism that guides the perforating machines. These marks are known to collectors as "electric eye" stamps. At the present time, all United States stamps produced from rotary presses are perforated by machines guided by the electric eye. The markings vary as experiments were made in putting the electric-eye mechanism into practice. The earliest markings were a series of heavy short vertical dashes dividing the sheet into right and left panes. Later markings are horizontal dashes placed at the other margin of the continous sheet of paper on which the stamps are printed. Still other markings which are applied to the margins of the steel plate and which, of course, print on the sheet margins of the finished stamps, are the registration marks to guide the printer when producing two-colored stamps. Each plate for each color is provided with a registration mark so that the printer will know when he has his paper in proper alignment. All of these markings are of great interest to collectors and help identify his stamps.

Stamp Printing - Part 1
Stamp Printing - Part 2
Stamp Printing - Part 3
>>Preparation Of The Steel Plate
Printing From A Line-Engraved Steel Plate
Photogravure And Rotogravure
'Printed' Stamps - Part 1
'Printed' Stamps - Part 2
The Wonderful Giori Press
Offset Stamp Printing