There are at least 3 factors, which contribute to flower colors (and shape):
- Temperature while buds develop impacts on antocyanin production. I have seen normally red Paphiopedilum bloom brown, when blooming out of season.
- Light while buds develop. See photo below.
- Flower age. Some flowers fade (like Bc. Edna below). Others intensify in color (from pale green to saturated yellow).
Notes on photo:
Bc. Edna opens almost coccinea (one of the parents) red, but fades through orange to near yellow. Notice how much wider the petals are on the greenhouse grown plant.
The hybrid at the bottom of photo shows 2 divisions of the same plant. Flower on left developed in the greenhouse. Flower on the right was on a plant that went to an apartment in Manhattan, some 3-4 weeks before the flowers opened.