These stamps are usually only available via approvals. Occasionally covers from interned persons, including from WWI and with or without postage stamps, are available. Please let me know of your interests.
The most often seen (though not often seen nowadays) Danish internment camp stamps are the so-called Tarp-Esbjerg 1946 stamps. This camp was apparently a refugee and stateless persons camp. (I am interested in obtaining more information about this camp.) The occupants included philatelists who created and printed these stamps in the camp. There are four types of stamps; each horizontal row of four stamps in the sheet included the four types. They are found as mint 4-strips and the four singles, canceled singles, and on covers. Canceled examples often bear GULDAGER postmarks.
The four types of the stamp design differ in two ways: The outer frame line is either solid or braided; the corner ornaments point in various directions (I refer to the bottom left ornament).
1946 Tarp-Esbjerg Internment Camp Stamps. Canceled VF complete set of all four types (solid vs braided outer frame; lower left corner ornaments point in different directions within a frame type). Imperforate as always, with ample to huge margins, including some margins on each stamp showing the dotted cutting lines. The cancellations are matching; they are indistinct and may not be correct (or they may be camp-applied cancels) -- I have previously seen this cancellation type on loose stamps, but I do not recall seeing this cancellation type on covers. Canceled examples (or uses on covers) are seldom found. This is the only canceled set of all four types that I can recall having in 50 years.
ACTUAL item.