I dont think anyone minds. The more we go back over these things the less we have to think about them
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Light is by far the largest part of the purpling effect but I bet if you got really purple leaves on your phals, I would just about bet the flowers are purple too which adds more purple coloring to the leaves.
if your phal is white the leaves arent going to be so purple or have much of a reddish tint to the leaves. the purpling tells you, you are at the high side of light the plant can use and its putting on some sunscreen