As far as I can tell, the second photo posted by scotroutes should be the correct colour, according to other colours around it; the obviously white wedding dress, the plastic chair, and the flesh-tones are all exactly as I would expect them to look.
The first photo is clearly subject to issues due to the exposure at the time, the background is totally blown out for a start.
Whites take on a bule/grey tone under certain circumstances, like white snow in shadow on a sunny day goes blue, otherwise is neutral grey, which is probably why it looks like a white dress in shadow.
Quite why the black trim looks like a brown/gold colour I don’t know, something to do with the actual fabric, I guess.
I would always try to find something that’s clearly neutral in colour to set the colour balance in a scanned pic, then set the whites and blacks at 5/95%, so there would always be a dot in the whites and blacks when printed.
I’d be screwed with that top photo, the sleeves look pretty close to a 45-50% neutral grey.
If I’d then had it pointed out that the true colour is a deep blue, shading into purple, with black trim, my response would be’wtf!?’ 😯
I think I’d demand a colour sample before I’d believe it.