Graduation ceremony and colors, need some advice...

[Nathan]

White tuxedo shirt and black bowtie with a Prince Charlie. Do otherwise at your own peril. If you want to go all black, at least wear an Argyll with a dark shirt and long tie. Not my preference, but better than bastardizing black tie attire with a coloured business shirt which is not appropriate for formal attire like the Prince Charlie.

If you're going to deviate from the norms, nobody can stop you, but then, why ask?

Plain flashes are preferable to tartan. Blue on the black hose would be rather nice or Red as Jock mentioned.

[Kinth]

bastardizing black tie attire with a coloured business shirt which is not appropriate for formal attire like the Prince Charlie.

I've been unclear: the shirt I intend to wear will be a tailor-made custom shirt, with tuxedo collar and cufflink wrists, just another color, not a business shirt... But I get your opinion, thank you for your answer !

[Jock Scot]

Of course go for a dress shirt(UK terms)formal (everywhere else?), but white is still your best option, but please, PLEASE get a dress shirt with a turn down collar.

[Kinth]

Edit: I'll have to find out what's a Tuxedo collar, as I was confusing with turn-down ones when I answered Nathan.

Edit 2: ok, I'm definitely too tired, I can't even read and asked the difference between a turn-down collar and a turn-down collar... Sorry, I'll come back tomorrow.

Edit 3: ok, let's do this: are "wing collars" suitable? Here they are the standard choice with bow ties... And my white "just in case" shirt is a wing collar one...

[Creag]

I agree with most everyone that a white shirt is the best option. But I can also imagine a black tuxedo shirt working out with this outfit. Or maybe a dark grey shirt, since you are having it custom made?