Very few facts are known about the British falsettist Frank Colman, there is no picture and nearly no personal data exist, obviously, his career was quite short. He made some recordings in the late 20s and the early 30s and sang together with the Maurice Winnick Band in Manchester, where he recorded six discs. Possibly, he is identical with Frank Ivallo.

He sang in easy sounding productions, his range can be estimated only very roughly, perhaps:
b - b'' (B3 - B5)

links: Video with Frank Ivallo

1. Chime again, beautiful bells (historical countertenor recordings)
Pearl OPAL CD 9848
Thank you very much to Silvain Blanchet for the hint to Frank Ivallo!