Sun/Lighting - Just can't seem to get it right! :(

[butterfly_muse]

Evening, all!

I am still trying to adjust my cattleyas to my window, and I am running into some conundrums. They are in a western facing window sill, which has an a/c vent underneath of it which provides cool, circulating air. I also got a big 3 ft by 3 ft piece of lace fabric, which I hung up against the window to cut/filter the light coming in near the end of the day when the sun hits that window directly. There are some trees outside, but for a period of an hour and a half or so the sun is above the trees. They are on top of a humidity tray, I mist them when it starts to get hot at that time of day, and they have their own little fan with them on the window sill to try to keep them cool and keep air circulating.

And yet their pbulbs and new growth shoots are getting purple, still. Do I need to get something not as hole-y as lace? Like a diffuser screen instead to go up against the window? Do I need to put another layer of lace over this layer? Or is it just because it's so damn hot, as most of you know, suddenly this week? We hit 97 today with a heat index of 103-110 in some places in the state and it's supposed to continue like this all week. They are as far back on that window sill as they can go and given that there's an air vent in the floor there I can't really put furniture over it to hold them. Also I think my fiance would have a big issue with me leaving the blinds up while we're gone during the day if I did shuffle them back another 6" or so onto a bookshelf that is next to the window.

What can I do??

Edit: I have moved them back further and to the back of their little plates since that photo was taken. It's just dark so I couldn't take a new photo of what the light looks like through the lace...^^;;