I've never come across this term before, so I'm pretty close to guessing --educated guessing perhaps, but education without actual knowledge is of limited value.

Seems to me that what the guy is trying to say here --at least in some of the quotes you give-- is something like "authenticated works," as in

"à départager ses œuvres autographes des copies"

"to separate his authenticated works from the copies"

I'm pretty sure that it is not a question of "signed" works --au contraire, it's a matter of works (whether signed or not) which have been "authenticated," i.e., assigned to the Oeuvre of the Master (rather than to one of his assistants, students or copyists) by Art Historians or Connoisseurs on the basis of the style and/or technique, etc.


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Note added at 57 mins (2013-05-03 17:39:45 GMT)
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That word "connoisseurship" refers particularly to evaluating a work of art from the point of view of its quality and (most relevant here) its authorship ("authenticity").

Connoisseurship is connected to Art History, surely, but somewhat distinct from that discipline in that it tends to imply this concept of "authentication" --in the Old Daze not authentication by empirical, "scientific" means, but rather by the much more "subjective" (or so it is asserted) standards which arise from Stylistic Analysis (though elements of "technique" may also be employed).

Among the greatest --or most famous (infamous?)-- practitioners of Connoisseurship was Bernard Berenson (c. 1900, q.v.), who was an "expert" on paintings of the Renaissance and made quite a bit of scratch advising wealthy clients (most notably Isabella Stewart Gardner) one what paintings to buy.

Since many of these were either not signed at all or, if so, were of questionable "authenticity," Berenson's Connoisseurship skills were brought to bear before the patron cut her check.

Most of Berenson's calls were (or have been "proven" to be) correct --but there have been a few which have been called into question, to the partial tarnishing of his name.

"Authentication" is also necessary when dealing with "workshop" products Virtually all the most famous "early modern" artists --sculptors as well as painters-- ran workshops (once their fame really caught on), in which students and assistants did a great deal of the "grunt work" (original blocking out, background painting, etc.). Usually the Master did the original design/composition and the finishing touches and also signed these, but sometimes not.

I'm talking about Michaelangelo, Rembrandt, Rubens, Titian, etc. --all of them had students/assistants who shared the work of cranking out "works of art" for a burgeoning and eager public

Even *signed* works by these guys have been --esp. in recent decades-- downgraded to a "School of X" status for various reasons, as Art Historians have uncovered new evidence which might suggest that they are not --or could not be-- truly works of The Master, but are mostly by his "School" (either his students, assistants or even copyists).

True Connoisseurship has fallen somewhat out of favor in the last 50 years or so, mostly due to the fact that it is, in the main, a skill which is simply no longer taught --and also because it does (seem to) involve that element of "subjective" judgement which is so anathema to the profoundly "Positivist" inclinations of our own era.

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Note added at 1 hr (2013-05-03 18:02:03 GMT)
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Well, Germaine has indeed Got It --it's newly minted Jargon from some Hot House intellos who are out there on the Cutting Edge of making Nouveau stuff up as they go along, not least this nouveau connoisseurship b.s..

This presents something of a problem for the translator, however, since the specialized, Jargonistic perversion of the venerable word has yet to penetrate down to the Hoi Poloi level (or even to the level of the fuddy-duddy OED, which doesn't recognize this meaning of an ancient (though very rarely used word)

http://www.oed.com/view/Entry/13441?redirectedFrom=autograph...

I would *strongly* suggest that, if you, Gal2, do use this word, it is placed within quotation marks and accompanied by an explanation of it's new meaning within the context of "nouveau connoisseurship."

Otherwise, only the most cognizant of the Cognoscenti among your readers will have a damned clue as to what you are talking about.

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Note added at 1 hr (2013-05-03 18:06:45 GMT)
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Having said all that, I believe that it would definitely be a mistake to use the rare English word "autography" rather than the original French "autographie" (in quotes) accompanied by at least a minimal explanation of what it means in the context of "nouveau connoisseurship."

It's Jargon, specific to a new (and, as yet, quite limited) "field" and inherently doesn't translate well --least of all by using an English orthography which refers to a word with a quite distinctly different meaning.