1862 set of 4 imperforate proofs on thin wove, the 1d in carmine-lake, the 4d in deep blue, 6d in slate-violet, 1s in blue-green, each with good to large margins and part strike of the dramatic 'SPECIMEN/NISSEN & PARKER. LONDON' H/S in blue, for use as printer's samples. Odd insignificant blemishes (1d with small thin, 6d with minor tones) but a spectacular and very desirable set of the highest rarity. Not known to Samuel in 1976 (but the 1d and 4d mentioned in the 1984 supplement). although first recorded in 1869 (!) by E. L. Pemberton, on the basis of examples in the collection of Judge Philbrick. Ex Latto, and illustrated on p.58 (fig. 5.4) of the recent book by Borromeo and Freeland.