Exposure to light has short- and long-term impacts on non-visual responses in humans. While many aspects related to non-visual light sensitivity have been characterised (such as the action spectrum for melatonin suppression), much remains to be elucidated. Here, we provide a set of minimum reporting guidelines for reporting the stimulus conditions involving light as an intervention in chronobiology, sleep research and environmental psychology experiments. Corresponding to the current state-of-the-art knowledge (June 2019), these are ( ) measure and report the spectral power distribution of the acute stimulus from the observer's point of view; ( ) measure and report the spectral power distribution of the background light environment from the observer's point of view; ( ), make spectra available in tabulated form, ( ) report -opic (ir)radiances and illuminance; ( ) describe the timing properties of stimulus (duration and pattern); ( ) describe the spatial properties of stimulus (spatial arrangement and extent), and ( ) report measurement conditions and equipment. We supplement the minimum reporting guidelines with optional reporting suggestions and discuss limitations of the reporting scheme.