The Useful Blank in a Short Label
A short label is not a shrunken version of a long essay. It is a decision about what to leave blank so the visitor's eyes have a reason to go back to the object.
If the caption points to a riveted repair on the rim of a porcelain bowl and stops there, the visitor will spend ten quiet seconds tracing the crack for themselves. Brevity works when what is missing from the text is sitting right there in the case.