In medical imaging, a fiducial marker facilitates tissue image correlation that allows for image analysis, normalization and correction of the optical exposure and spectral and spatial distribution in order to compensate for the surface reflections, sub surface tissue interactions and spatial orientation of the excitation and imaging axes to the subject tissue. Using a cross comparison, clinicians can model tissue image data in different forms in order to reference and compare data from various spectral components and or from different images. This may enhance human interpretation between images including the variations between images even when the spectral, spatial and optical conditions or the image resolution or sensitivity are compromised. Such may be used to assess cosmetic, moisturizing, therapeutic materials and treatments.