The obvious disparity between neighboring televisions on display in a store amply demonstrates that even identical (and brand-new) video devices can differ dramatically. When mixing multiple cameras we need to ensure that their output matches. Switching to a camera with obviously different color characteristics will be seen as a glaring error by your viewers.
Even when we restrict matters to a single unit, color characteristics can change as the system warms up, and as it ages. For this reason, it’s important to allow a device to warm up before attempting to calibrate it.
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