[radeklew]

Could it be called an ink coating? My understanding is that the distinction between ink and pigment is that ink is a solution while pigment is a suspension, can there be both kinds of coatings? or is it a meaningless distinction to draw in this context?

Sorry to barrage you with these questions if you don't know, but you brought up a pretty fine point so you seem knowledgeable about this :)

[mc32]

I'm no expert but in industry (and it may differ from company to company) coatings is mostly paints and inks are separate. Inks usually permeate (and add coloration to) a medium while coatings/paints bind and coat (to) a medium.

[jbay808]

Anodized aluminum forms a porous surface that is dyed with ink to colour it, if I recall correctly.