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This photograph, by William Friese-Greene the prolific inventor and portrait photographer, would appear to be signed in ink just under the photograph (which is thin paper stuck onto the cardboard mount) and also on the back, just above the printed studio address. Strangely, the signature appears to be slightly different when comparing front and back.
This is from Wikipedia:
William Edward Green was born on 7 September 1855, in Bristol. He was educated there at Queen Elizabeth's Hospital. In 1869 he became an apprentice to a photographer named Maurice Guttenberg. By 1875 he had set up his own studios in Bath and Bristol, and later expanded his business with two more studios in London and Brighton. He married Helena Friese on 24 March 1874, and decided to modify his name to include her maiden name.