I hate to be the naysayer, but other than that leaf tip, your plant looks awfully happy. I agree that if it fertilizer burn or something of that sort, you'd think you'd see it on more than one leaf. Then again, if you had a disease or something, you'd think that might be more than the tip of one leaf as well. I'd consider lopping much more of that leaf off, if it concerns you. That's a pretty big sized plant - personally I wouldn't worry about saving one leaf if you think that leaf has something funky going on.

I have a Paphiopedilum Greyi which looks very much like your plant.

It’s interesting that this post came up at this moment. I was going to open a post about nightly temperature treatment of my own paphs. I have a warmer-growing multi-floral type and a couple of “mottled leaf” types. So, answering your post taught me something as well – that there is a difference in culture between your type of plain green foliage type, which are cooler growing, and my type of plain green foliage multi-floral type, which is warmer growing. The thing is, if you’re trying to grow in a house, the ability to provide truly cool temperatures at night can be challenging. And although all orchids do well with a temperature differential between day and night, my feeling is that paphs in particular will be more rewarding with some daily cooling off. Except when temps are drastically low, I’m moving mine into a “cool room” at night, with the windows cracked. The temps in there this time of year can be into the 50s. My catts can just get over it. Not moving those. And not moving warm growers. Theres a little bit of temp difference at night in their regular growing space. But the paphs I’m going to pay particular attention to.

Mike - I know what you mean. I could hardly believe my eyes seeing these gorgeous paphs. They’re like jewels. But you know, the goal is to get better all the time. You're on the path. You'll get there. After seeing the paphs in that show, I'm tempted to specialize my collection mostly to Paphs. One of my two bedrooms is used as study. Who needs a study anyway? I can close it off completely. It has two windows (not for light, but fresh air and climate control), and a long baseboard heating duct, which can be adjusted. So I can really take the night temperatures down in there in the cool months, and exclude, or control A/C in there in the summer. Lots of fresh air year-round. Best of all, there's a wall-to-wall waist-height bookcase. The top of it just runs straight from one wall to another, a freaking 11 feet long and 12" wide. Nice for a diverse collection of paphs under lights. I can feel my heart-beat racing !! Thanks for your patience in reading this. I’m talking myself into this idea, in the guise of a post.