It looks like sun burn, looks like it was from a while ago. The new leaves look good so I don't think you need to change anything.

New York City and we just had a short lived heat wave with very high humidity. Judging from that link, it looks like a combination of sunburn and cold damage. My main concern is that it is discoloring the main stem besides the bottom leaves.

As James said, the new leaves look healthy... so maybe the worst is over?

Everything else looks good and the stalks and flowers look wonderful.

Do monitor carefully and if it starts to get worse google Rv orchidworks and join the forum. They have some very knowledgeable people there with 40+ more years of experience.

direct sun on a phal can cook it fairly quickly, only takes a few minutes...

As you can see here, some say 'sun no problem' and you say it is...decisions, decisions..LOL I suppose if I remove if from the sunny area, all that 'whitish' will disappear? I am concerned for the main stalk starting to show whitish.

The sunburned areas are permanently damaged and will not go away, but the damaged leaves can live on for a while and still help the plant. Eventually they will get old and drop as all orchid leaves do.

I would not leave the orchid where it gets so much sun. If you must, at least try to shield it a little bit, either with another plant, a shade, a curtain ... something.

I keep my phals where they get a couple of hours of early morning sun. A couple are acclimatized to it, and they've never burned. I hide my smaller ones behind the larger pots of Oncidiums (which love the sun). This way, they get bright light, but no direct sun.

Well, that is exactly how it got the sun...its in the morning, but honestly longer than a couple of hours at this time of the year. I brought it in, its almost 3' feet in height. The area that I had it in would be sunless in the afternoon, but I do not like the idea that I have to make note of it daily and put it out each afternoon Thanks.

How about hanging a thin white laced curtains on the window to absorb some of the sun rays? Or possibly covering it with a very light tint as in tinted windows.

You misunderstood, my problem was that I had it outside in that morning sun. Inside, no problem...but everyone says that it would do the Orchid good if you put it out during the Summer months, and that was what I was trying to do.

Latitude makes a big difference. Bright shade and zero to nil direct sun is best. There are exceptions. In New England, due to latitude it can tolerate some direct sun at different times of the year. Keeping phals in Florida vs. NY is much different rules on sun...

You don't have an overhead or some trees that you can put it under? How are you at building things? Using 2 x 4's, some slats and you can build an enclosure with slats on top and or sides which will reduce sun exposure.

Even here in Boston, anything more than 2 hours of direct sun is too much for my phals. I've burned more phal leaves by keeping them outside in the summer than I care to admit. I've brought them back in because I can't sufficiently shade them and also keep them out of harm's way from critters. I suggest no direct light in the summer for phals.

Put it out under a tree or shrub. If your plant is on a balcony, you can use a patio umbrella. I have grown Phals outside on a deck in very strong light and used patio umbrellas to give the Phals shade.

Jane

make sure you bolt the umbrella down to something heavy, a light breeze will move the umbrella and then you get sunburn pretty quick, someone (who has killed many orchids) further up on the post mentioned some key information about phales and

sun light "direct sun on a phal can cook it fairly quickly, only takes a few minutes..."