Very little is known about Mr J. Brockmer. No examples of his work have been found and all information comes from advertisements. Brockmer appears to have worked from the early 1760s to the mid 1770s from a small establishment known as The Golden Head in Covent Garden, London. He was willing to paint in miniature on a variety of objects including Cabinet Pieces, Bracelets and Rings.
Source: McKechnie (Author of, British Silhouette Artists and their Work 1760-1860)
Brockmer, J. (McKechnie Section 2)