I'm not a Phal expert, but I believe your black marks are from sunburn. A West window is not the best for Phals especially in a zone 8b as in your profile.
As Ursula suggested, you really need a sheer on that window. Phals cannot take direct sunlight.
The best way to understand the way orchids take light is that in general, the bigger wider dark green orchid leaves need less sunlight (or cooler filtered light) than the lighter green narrower leaved plants.
The reason for this is that the wider surface area of the big leaves allows for a larger collection of sunlight (hence the reduced need for direct or bright light).
Phals - semi-shade or filtered light similar to Hostas in your garden or African Violets on your windowsill.
