Guide Dots:
Guide Dots were placed in a systematic manner on each printing plate to help the siderographer align the transfer roll die reliefs onto the correct transfer spots on the printing plate. Dr. Chase's book explains this in exacting detail and this study will not repeat that information. The relevance of guide dots in plating is that guide dots help the plater locate the stamp on the plate and also provide a very useful Plating System "point of comparison" for plating the stamps. The point of comparison exists because each guide dot is inexactly placed on the printing plate and there can be quite a bit of variance, even though they are supposed to go in appropriate places on each plate. Thus it is possible to evaluate the exact placement of the guide dots and find stamps with similar placement to evaluate for plating.
The drawing below, excerpted from Dr. Chase's book show the theoretical placement of guide dots for the left and right panes of the 200 position plates:
As shown above, guide dots can be located near any of the four corners of a stamp or stamp margin. Theoretically, there are 26 Upper Left Guide Dots (UL GD), 260 Upper Right Guide Dots (UR GD), 104 Lower Left Guide Dots (LL GD), and 936 Lower Right Guide Dots (LR GD) for the 2,600 stamps. However, due to missing guide dots, the actual quantities in the plates are smaller as shown in the table summaries and detailed stamp data in this study.
The lower right guide dots are the most numerous, so the most likely to focus on for additional study in the Plating Wizard. Version 2.0 planned for this study intends to include guide dot positioning as an additional plating characteristic. Other than misplaced Reliefs, of which there are a number, the lower right guide dots are positioned with B Relief stamps. Examples of lower right guide dots variatons in positioning are shown below:
