Ó Lochlainn, Colm (1892–1972), printer, publisher, and Gaelic scholar, was born William Gerard O'Loughlin at Drumcondra, Dublin, on 11 October 1892, the second of four surviving children (from six) of John O'Loughlin, publisher, and his wife Delia Bridget (née Carr), whose family were printers and who engaged in small-scale property speculation on her own account. Ó Lochlainn was educated at Belvedere College and at St Mary's College, Rathmines, run by the Holy Ghost Fathers, where he distinguished himself in French and Modern Irish, before entering UCD in 1910. He studied under Eoin MacNeill (qv), receiving a BA honours degree in Celtic studies in 1914 and the MA in 1916. His MA dissertation, ‘The roads and highways of ancient Ireland’, received the O'Curry memorial medal. In 1914–16 Ó Lochlainn was an assistant master at St Enda's School, Dublin. He joined the IRB in 1913 and was one of the founding members of the executive of the Irish Volunteers in November 1913. At the same time he became well known as an amateur actor with the Theatre of Ireland in Hardwicke Street; this was funded by Edward Martyn (qv) and was regarded as simultaneously more nationalist and more cosmopolitan than its better-known rival, the Abbey Theatre.
In 1915–16 Ó Lochlainn published the aggressive separatist weekly The Spark, contributors to which included Patrick Pearse (qv); shortly before the Easter rising he printed copies of the ‘Castle Document’, which indicated an imminent crackdown on the Volunteers, and which Ó Lochlainn later came to believe had been forged by Joseph Plunkett (qv). In 1915 he was appointed to the Volunteers’ military organising committee, chaired by Plunkett. In the days before the rising Ó Lochlainn was sent to Kerry by Plunkett in an abortive attempt to disable a radio station at Caherciveen, which ended with the deaths of three Volunteers in a car accident; his account of this event (written in 1920) was published in the Dublin Magazine in July–September 1949. Ó Lochlainn was associated with the MacNeillite faction within the Irish Volunteer executive, and was saddened by the extent to which the Pearse faction were prepared to deceive their colleagues in preparing for the rising; he was one of the couriers who disseminated MacNeill's countermanding order to provincial Volunteer leaders – his errand was to Coalisland, Co. Tyrone. After the rising Ó Lochlainn worked for Sinn Féin in elections and ‘various subversive activities’ but did not make politics his central concern and refused requests to stand for the dáil.
In 1920 his father's printing firm, O'Loughlin, Murphy & Boland, became insolvent. Between 1917 and 1920 Ó Lochlainn had published twenty-three limited edition political and literary titles, including Hunger by James Stephens (qv) and History of the Irish Volunteers by Bulmer Hobson (qv), under the ‘Candle Press’ imprint, operating initially from the family home in Rathgar but then from the Craftworkers’ Studio in Dawson Street; he also produced prints and cards. He was awarded the RDS silver medal for bookbinding in 1925, and the Tailteann medal for bookbinding and decorative art (bronze 1924, silver 1928). In 1926 Ó Lochlainn founded the Three Candles Press, based in Fleet Street, Dublin, which he presented as following in his father's footsteps (he employed his father as a sales representative to help him to pay off the debts accumulated by the older firm).
In 1937 Ó Lochlainn introduced his ‘Colmcille’ version of Gaelic type, designed with the artist Karl Uhlemann for the Monotype Corporation; this was a technical and artistic triumph but not a financial success. He also produced the ‘Baothin’ display type modelled on German ‘Hammerschrift’. Éamonn de Búrca argues that in the 1930s Three Candles ‘vied with the rest of the world’ in the production of craft printing work of ‘the highest standard’; Ó Lochlainn was closely involved at every stage of the production of the company's books. He treated the press as virtually a non-profit enterprise and was concerned to maintain good relations with his forty employees rather than to maximise financial returns. He made his living from lecturing to librarianship students at UCD and to printing trade apprentices at Bolton Street Technical School, where he was a director of the Dublin School of Printing and Book Production from 1929. He also lectured in Modern Irish at UCD, 1933–44; he was a scholar of Scots Gaelic as well as Irish and in 1960 was awarded an honorary D.Litt.Celt. by the NUI. He was a co-founder of the youth hostelling organisation An Óige.
From 1929 until the late 1940s Ó Lochlainn edited the Irish Book Lover, for which he wrote extensively. His Irish street ballads (1939) and More Irish street ballads (1965) became standard collections, influencing such musicians as Ronnie Drew of the Dubliners folk group. Ó Lochlainn had a fine singing voice; he and his sister regularly sang on 2RN, the Dublin radio station, in its early years. He was also a piper; he learned the art from Jimmy Ennis whose son the well-known piper Séamus Ennis (qv) he employed as a clerk at the Three Candles Press. He also published Anglo-Irish song writers since Moore (c.1950) and The fishery at Casla: Conamara, its history and records, 1864–1956 (1957). He had acquired the Casla fishery in 1954 and became involved in a bitter dispute with a family of tenants, whom he evicted; this damaged his reputation locally.
Ó Lochlainn died 26 June 1972 in Dublin after a lengthy struggle with cancer; he disposed of the Three Candles Press to new proprietors shortly before his death and it continued to trade under that name until 1989 when it became the Aston Colour Press. He married Ailish McInerney, with whom he had two sons and a daughter. The elder son, Dara Ó Lochlainn (1939–92), jazz musician and graphic designer, was born in May 1939. As a teenager he studied at the London School of Printing and Graphic arts, where he distinguished himself. He subsequently lectured at the Oxford School of Printing and in Dublin at the National College of Art and the College of Marketing and Design. At the same time he ran his own design company; towards the end of his life he was commissioned to produce a digital version of his father's ‘Colmcille’ typeface. His strongest interest, however, was jazz (which his father described scornfully as ‘brothel music’). He began his jazz career at the Green Lounge on St Stephen's Green in the late 1950s and remained at the centre of the Dublin jazz scene for the next twenty years as a singer and musician. He had a considerable reputation for verbal and visual wit (the latter expressed through impromptu drawings) and was nicknamed ‘Naybor ’ (his usual form of address in conversation). In the mid 1980s he published Jazz News International magazine, widely considered to be the best English-language jazz publication in the world. The publication of the magazine (and his career as a jazz singer) ended about 1988 when surgery for throat cancer led to the loss of his voice; however, he continued to play jazz and to communicate through a special microphone, and he was a regular reviewer for the Sunday Tribune newspaper. Dara Ó Lochlainn died 20 December 1992 at Harold's Cross Hospice, Dublin, after suffering from cancer for seven years.