This is a modern horror story about an innocently misbehaving projector, and why we beseech everyone to report minimal col- orimetric data about stimulus displays. We present anecdotal experience of configuring a projector to display video stimuli in a high-tesla MRI room, along with all the gotchas, (broken) technical assumptions, and theoretical rehashings that should be considered by every scientist who uses computers to dis- play visual stimuli. The moral of our story is: (1) check that your monitor/projector is actually showing the colors and lu- minances that you think it is, (2) make explicit assumptions regarding the physical/perceptual space of your stimuli and how they relate to any model analysis you will perform. This is especially important when modeling non-human animals, since most equipment and data formats implicitly assume hu- man perception. We show that innocent changes to display settings such as brightness reduction can cause dangerously unexpected results. Understanding and reporting colorimetric data in scientific publications is important for two reasons: (1) reproducibility, and (2) model fidelity.