Glamorsidhe, I gather that you do not know how forensic and scientific analysis are done in conjunction with authentication in many cases.
Examples of which are chemical/microscopic analysis of the paint/ink, paper, canvas, wood, etc. There is also research done at times of historical documents/photos.
I'm well aware of what you say regarding forensic & scientific analysis done within many, if not most, art authentication situations, & the various chemical & electromagnetic analyses performed on the diverse substrates, paints, inks in order to determine the materials' specific historicities (eg, whether a specific ink/paint color was ever used by the artist in question, or if some of the materials were even available during a specific time frame, etc.), but
none of these things actually "prove" that a specific artist created a specific art piece: all this data helps, but
specificity is never proved so much as inferred (was it artist "A" or artist "B" working in the manner of "A", particularly when dealing in "forgeries" or "imitations" of specific names, paintings, etc. who did the actual art piece?). If it was simply a matter of scientific examinations of artwork & research therein authenticating things, you wouldn't need the "judgements" (opinions) of so-called experts determining if the art in question was actually done by a specific artist at a specific time & hence "genuine" as opposed to labels of "attributed to" or "working in the manner of" or a plethora of other semi-namings or classifications but not full "authentications" of artworks --- nor would there still exist,
as many professionals attest, within many museums & art galleries questionable if not actual copies or forgeries of art being exhibited! Art authentications deal virtually with
inferred conclusions based on a plethora of data, but rarely
certitudes deduced from that data.