This thesis is an autoethnographic exploration of how my music composition practice is influenced by my auditory-visual synaesthesia. I perceive music as coloured and textured shapes – ‘photisms’ – in my mind’s eye. There are few first-person accounts of synaesthesia’s impact on music composition processes and outputs. The aim of the study is to investigate how my synaesthetic experiences affect the music I make, through the creation and analysis of an album of electronic music titled Photisms. The accompanying textual document employs an autoethnographic method proposed by Chang (2008), providing a first-person account of my own synaesthesia and analysing how it influences my composition processes and outputs.