E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Margarine Substitute (A).
A mere imitation. Just as margarine is an imitation and substitute of butter.
Between a real etching and that margarine substitute a pen-and-ink drawing the difference is this: the margarine substitute is essentially flat but true etching is in sensible relief.Nineteenth Century, May 1891, p. 780.