I hadn't expected the white to be like a periwinkle or grey color too. Seems slightly different than the sample or maybe my perception is off? But it is so freaking awesome!!
I was super happy to discover that it was an off-white. I think photographing something with for a website that requires could colour realisation and detail inevitably means a lot of light, so the off-white looks much more like optical white. It is a stroke of genius and definitely contributes to the muted effect that others have mentioned, by toning down the contrasting colours in the shirt.
I tried my work shirt on with a few different denims, jackets and vests today, and there isn’t much it doesn’t work with.