Colmignoli was born in Arezzo, where he started at a very early age to work for a printer. We know little or nothing about his early years in Florence, up to 1851, when he started to work for the Tipografia nazionale italiana of Beniamino and Celestino Bianchi. When in the middle of the fifties the Bianchi brothers merged their firm with that of Gaspero Barbèra, Colmignoli followed the machines to the new and more modern premises in Via Faenza, where he worked at first as typesetter. Later on he became head printer, on account of the main qualities that Piero Barbèra, in his Elogio del proto, considered indispensable for best undertaking the job: memory, tact and, above all, tidiness. In 1870 the Barbèra publishing house opened a branch in Rome, recently made the capital of Italy. Gaspero Barbèra wanted to entrust it to his eldest son, Piero, but since he was only sixteen years old, he was placed under the guidance of Ferdinando Serafini, the director of the parent company in Florence. Giovanni Colmignoli was therefore appointed as his substitute, and became Gaspero Barbèra’s right-hand man, displaying his qualities as a calm man, never fazed by the problems to overcome nor the ill will to placate, so as to live – as Piero, who at his death wrote his obituary, recalled – “always harmoniously both with the men of letters, irritabile genus, and with his subordinates; rara avis, because often, as a result of frequent friction, there is more bad blood between workers and foremen than between workers and bosses”.

But it was above all his skill as a printer, acquired since he was an adolescent, and his technical preparation that made him an extraordinary professional, with the ability to find solutions for the most complex problems that were beyond the capacity of anyone else. Piero Barbèra cited in particular the national edition of the Opere di Galileo Galilei, for which Colmignoli was in charge of the typesetting up to vol. XII, plagued by technical complications and budgetary restraints, so much so that they caused him anguish even in the last hours of his life in the ramblings of his mind. When in 1902 the Barbèra brothers decided to sell the printing concern to the firm of Alfani and Venturi and to keep only the publishing house, they insisted that Colmignoli, even though he was old and in poor health, should keep his position as technical director. Antonio Favaro, demanding like few others when it came to the work of his collaborators, wrote of Colmignoli: “Besides his very many merits, he had also that of having assisted with diligence, patience and intelligence beyond praise in bringing about, as far as the part that involved him was concerned, this edition of Galileo, which, it must be said in all modesty, has received in all respects general approbation”. Giovanni Colmignoli died in Florence in 1909.