There is a lot of controversy over whether Opponent-processing theory is the best way to explain color vision. There have been a few experiments involving image stabilization (where you experience border loss) that produced results that suggest participants have seen “impossible” colors, or color combinations we shouldn't be able to see under the Opponent-processing theory; However, many criticize that this may just be illusionary experiences. Critics and researchers have instead started to turn to explain color vision through references to retinal mechanisms, rather than opponent processing, which happens in the brain's visual cortex.