The following commentary – alongside the portfolio of eight compositions which it supports – outlines a body of practice-based research which examines the way in which the notions of 'blur' and 'focus' may be explored in the context of contemporary instrumental music. Blurring is assumed as a compositional principle in order to engage with the further notions of 'revelation' and 'identity', whereby aspects of the musical material may be concealed within the global musical context until a critical point in the work's structure. Given the optical basis of the adopted terminology, analogy is drawn from photography and the visual arts, both in order to situate musical practice in relation to relevant critical theory, as well as providing a catalyst for unconventional musical inspiration. Notably, such analogy points towards the use of 'spatial modelling' as a means of conceptualising and structuring the blurring of musical material. The research postulates that, whilst the concept of blurring as a compositional principle and structural device is almost entirely absent from current musical critical theory, it is nevertheless highly functional in a musical context. Accordingly, practical compositional research, coupled with a review of musical and visual literature, is used to develop a theoretical framework surrounding the 'blur / focus axis', which operates as both a compositional approach, as well as an analytical tool for interpreting technical and conceptual aspects of related musical works of others.