From Museum Basics 3rd. edition - Timothy Ambrose and Crispin Paine
Box 38.2 What to say and how to say it?
Writing labels is an art. The label should include all relevant details, but not be too long; it should avoid vague or inexact statements, but give some indication of why the object is worthy of being displayed in the museum. Information should be verified before it is included on a label.
Examples of what not to include in writing a label about a sewing machine:
Sewing Machine. Believed to be a hundred years old.
A hundred years old - when? It is possible to date many historical items accurately; reference books including trade catalogues can be used.
Sewing Machine. Such machines were widely used in the early days.
The 'explanation' really adds nothing to our knowledge of the object.
Sewing Machine. This machine is unusual because it was made in America.
This lable would be inadequate unless it describes the only American-made machine in a collection of English-made machines. Even then information about the nature of the difference would be required.
Sewing Machine. Donated by the late Mrs Jane Smith.
In 50 years' time, most of your donors will be 'late'!