League of Nations (SdN) Album
(part 8 of a series)
Switzerland began using grilled gum (aka, geriffeltes papier) in 1930 to prevent mint stamps from curling or rolling into annoying tubes. Most collectors’ albums have smooth gummed stamps that refuse to flatten. The grill, a waffle-like matrix of tiny squares pressed on top of the gum, corrects this problem. It can be best seen on the back of mint stamps with undisturbed grills.
Courvoisier, the printer of many stamps for Switzerland and Liechtenstein, used a gum breaking machine to affix the grills. Sometimes, but not always, the thrust was heavy enough for the grill to be noticeable on the front of stamps and even on used stamps that have been soaked in water.
Dates and Scott numbers
Scott Catalog lists the grilled SdN stamps with the letter “a” following the number for the corresponding smooth gum types, thereby subordinating them to the earlier stamps. Scott also uses the same system for distinguishing grilled from smooth gum issues for regular issue Swiss stamps. In addition to the eight stamps shown above, grills were also applied to the issue with the Swiss coat of arms over the Matterhorn. See post #9 in this series
Magnification of a grilled stamp
Stamps that might have grills, but are attached covers, present an identification dilemma. If the grill marks are not obvious on the front of the stamp, a restoration specialist might be required to partly detach the stamp for observation. Of the stamps shown in this post, probably only #s 2o17a and 2o23a are valuable enough to warrant seeking a specialist.