Copy letter from Robert William Frederick Harrison to G [George] G [Gerald] Stoney FRS 'Before putting in hand the portrait of your late father, which is to accompany the biography that Prof. Joly has written, I should be glad to have your views on the process you would like adopted. The processes we commonly use are collotype, or something similar, which would cost you £5 or £6, or alternatively the more expensive photogravure process, which would cost you about twice as much. You will find portraits of both kinds in the Obituary Volume of Proceedings [of the Royal Society] (Vol. 75, 1905). I will wait to learn your preference before going any farther.' 2 January 1912