Perhaps black was chosen as the color that shows marks the least on stage, and perhaps distracts the least from the player? I don’t think any color is any more or less ‘professional’ (okay, maybe pink is a bit cartoony!), red didn’t used to be a keyboard color much except for Vox organs until Nord adopted it, now it’s adorning pro stages everywhere.

Bottom line, a ‘professional’ color is whatever the hell professionals use. Make a brilliant sounding keyboard in pink, bet you pretty soon pink is considered ‘pro’!

Let me assure you, after decades of playing outside on Florida beaches and decks, it doesn’t matter what color the keyboard is. Half an hour in bright sunlight, and even a white keyboard will melt! And long before that, the display will overheat and cease to function. I pass on gigs that aren’t covered, no matter what color keyboard I use!