Leaves Turn Purple Under New Light

[Stray59]

I also think it is a light issue. You can always check this by putting a little piece of black tape on a green area and then face it toward the light; if it is a light issue, the area under the tape will remain green while the other turns purple. Phalaenopsis tend to show a lot of purple under strong light and they often develop purple under the leaves regardless of the light.
I would be careful though, as this is sort of an mild orchid sunburn. When I get this reaction, especially if it is wide-spread, I move the plants out of the light a little more, or move the light further away. The development of purple on the upper leaf is the plant trying to shade itself, just like a human tan. The better bulbs are giving better light, so the plants are trying to accommodate that by turning dark. If the light were any stronger I believe that you would see burn area develop.
If they were mine, I think I would move the light to 9- or 10 inches away, as they are obviously at their peak of light absorption.
They look really strong! Good luck -
Steve