I was reading an article I don't remember where; it was comparing baroque composers, who is prominent and who is not. Those who are not where described by an idiom (I remember it was something like "day working composer") which meant an ordinary composer. Can you please help remember this idiom?
As k1eran says, "journeyman" is correct. But for more informal use, you might be thinking of "workaday", which is somewhat more disparaging.
1. of or befitting working days; characteristic of a workday and its occupations.
2. ordinary; commonplace; everyday; prosaic.
"Hack" is even worse.
In the years following the success of the 1979 play (and then the 1984 movie) Amadeus, it became common to refer to a composer—and especially a baroque composer—of unexceptional talent as a Salieri. But that's not to say that the real Salieri wasn't prominent in his day—he was (at least in Vienna). But after Amadeus, his name became synonymous with "court composer"—a designation that implies a comfortable but superficial milieu and pedestrian talent.
Interestingly, authors before Peter Shaffer sometimes treated Salieri as a foil for composing genius (in the person of Mozart). For example, from Twentieth-Century Literary Criticism (1979):
NADEZHDA MANDELSTAM (essay date 1972)
"In every poet there is both a Mozart and a Salieri," [Mandelstam said]. . . .
Like Shaffer, Mandelstam presumably picked up the idea of treating Salieri as a kind of archetypal mediocrity from Alexander Pushkin's "Mozart and Salieri" a play in The Little Tragedies (1830).
But the term became much more frequent after Shaffer's play and movie. From a review of Amadeus in Musick, volume 7 (1985):
It is easy for a critic to point an accusing finger at a "Salieri", but the fact is that unless we point out the true "Mozarts" as well, we arc nothing but "Salieris" ourselves. Therein lies the authenticity and truth of Amadeus.
And the name now appears in as a synonym for artistic or professional mediocrity even when music is only tangentially (or not at all) the main subject of the discussion. From Joseph Keleda, Integrating Reengineering with Total Quality (1996):
People who play bridge, tennis, bowling, or golf would no doubt abandon these games if no measures were involved; the Olympic Games would not exist; a Mozart would be held in no higher esteem than a Salieri — life would be very boring.
And from Bernard Boar, The Art of Strategic Planning for Information Technology (2002):
The frustrating challenge confronting all of us who seek strategic wisdom is that there is a chronic surplus of Salieris and an ever-acute shortage of Mozarts. ... I am fearful that many who present themselves s oracles of strategic advice are but modern day Salieris. Few have known strategy as deeply as deeply and in the manner as have Sun Tzu and Machiavelli, the Mozarts of strategic thinking.
From Jeffrey Di Leo, Affiliations: Identity in Academic Culture (2003):
Having a connection with an LSI [low-status institution], the authors of this piece obviously have a stake in the outcome. It is likely that some will see us as Salieris—mediocrities who simply cannot accept our own lack of talent. But if the top law reviews are acting unfairly, self-interest is irrelevant; it's generally understood that unfair practices are going to be challenged by the people who stand to benefit from their elimination.
Perhaps journeyman composers, since the journey in late Middle English meant a ‘day's work’.
From etymonline.com :
journeyman (n.) "qualified worker at a craft or trade who works for wages for another" (a position between apprentice and master), early 15c., from journey (n.), preserving the etymological sense of the word ("a day"), + man (n.).
Deprecatory figurative sense of "hireling, drudge" is from 1540s.
Its American English colloquial shortening jour (adj.) is attested from 1835.