This may or may not be relevant to this conversation, but in Australia, Dulux Trade Centres are selling a colour scanning device called the
Snapshot.
Dulux have had for some an app for you phone that allows you to take a picture of a painted surface to find the "Name" of that colour in the Dulux range, to then allow you to go and buy the paint you liked so much on your friends dining room wall, your neighbor's fence, or your landlord's apartment.
Now, the Snapshot will also allow you to do that as well, but it will also record the colour tint to allow a match if the colour is not a propriety Dulux colour.
Is this likely to as good as a spectrograph? I doubt it. Is it likely to be able to record a colour to enable a batch of "very close" auto enamel to be tinted? Probably. It's not the answer for everyone, but it might suit some.