I haven't developed the habit of taking measurements. The possibility of actually making physical contact with the bloom (and a nightmarish vision of an apparently pristine flower dropping onto the bench) makes it a risk I'm not willing to take. I'll settle for pictures.
For those of us lucky enough to visit greenhouses not open to the public a thread on greenhouse etiquette might be of interest.
My guess based on the bud near it and the inflorescence would be 8-9cm. Which is quite nice considering the shape of the flower. It could be bigger, though.
As to greenhouse etiquette. If you were in in my greenhouse fondling my flowers, I'd whack you in the head. Or at a minimum bark really loud... So, you were correct in not wanting to touch it. I think that is more a function of me not knowing your skill and coordination level. Clumsy customers have broken or bruised a lot of my nicest flowers. If I knew someone was an accomplished grower or orchid judge, I suppose I would be not be as concerned, but I still think it would be nice to ask before touching.
It is equally nice to ask before photographing. I'm not a big time breeder, but there are a few plants in my collection I wouldn't want pictures of floating around. Why? Well, if they are really nice I want copyright control over them, and wouldn't want my plant used to sell somebody elses. So I might veto for that reason. Or, a plant might not be up to my standards and I wouldn't want that image associated with my name. Or any number of reasons.
Besides Ratcliffe [Fla.], Fox Valley [and you know Tom K. is never there], and H.P. Norton's I've never been to a greenhouse. All the vendors were actually quite nice about letting me pick through the plants. I haven't had as much fun as going through the plants w/ H.P. in quite a while. :rollhappy:
I'd let you pick through my plants too... Like I said, if you look like you know what you are doing, and aren't pawing through things like an elephant at a salt-lick, I'm pretty cool. Just ask first. *grin*
Admittedly, a poor photo, but it illustrates the challenges inherent in selecting the best for further breeding. Selecting from the remainder those to be sold as 'select' is an even more daunting task. At the time of this visit only the studs had been culled, so the real work of grading the remainder had yet to be accomplished.
At this point nearly any buyer could find one to their liking from this group. This can be a challenge, as the sheer numbers indicate that one might find a real gem if willing to spend the time to thoroughly scrutinize the blooms. Your success in this respect will be proportional to the amount of time you dedicate to this task. If you do find a really exceptional flower you should expect it to be priced accordingly. 'Accordingly' may be based upon a number of factors, not the least of which may be your abidance of 'local rules' for greenhouse etiquette. It hardly matters what sort of behavior other growers may tolerate. Local Rules always apply. These rules are not always clearly defined, and may be modified at the discretion of the grower. If you are uncertain of which rules apply locally, assume the most stringent and let the grower declare otherwise.