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The process varies somewhat according to the differentmachines that may be used. The flat-bed machines usuallyperform all of the work described excepting only thecutting of the blanks which are always prepared aheadof time. The rotary machines usually perform only theprinting of the stamp while the folding is done on othermachines. Either flat-bed or rotary machines are capableof printing both the stamp and the corner card in thesame operation, there being separate ink fountains pro-vided for the different colored inks. Quite obviously the constant striking of the printingdie against the tympan will in time cause the die towear and will also wear down the tympan. The resultingstamps will, therefore, show some differences which areoften startling. While in general and as long as the |
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