What were the specific chemical properties of the photograph of Sai Baba that Madhavrao received? Was it a silver gelatin print or some other type of early photography?

The provided sections of Chapter 51 do not offer any details regarding the chemical properties or the specific photographic process used for the portrait of Sai Baba. The text describes the portrait as 'all-captivating' and 'beautiful and holy,' focusing on its spiritual impact on Dixit rather than its physical or chemical composition. The events detailed in Chapter 51 are centered on the miraculous circumstances surrounding its acquisition and the subsequent journey to Shirdi, not on the technical aspects of the photograph itself.