Catt hybrid leaf colors

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The objective is a lighter green color, right? However, I have some catt hybrids (Blc, Lc, etc.) that tend to have very dark green leaves, even with a pretty intense exposure to sun. A couple receive a short period of direct sunlight on my back porch (summering out doors). I watch them carefully. All of them, dark and light, have new growths, and none seem to be displaying the reddening of the leaves (well, the Rhyncholaelia digbyana is getting a tinge of red along the leaf edges). Please fill me in on the small details, fellow catt lovers! Thanks.