In his excellent article, “Georgian Palaeography”, J. Neville Birdsall (1928-2005), after listing some reproductions of Georgian manuscripts, has the following to say (p. 95):
The aspirant in Georgian palaeography must use these and every available photographic reproduction, but it cannot be too much emphasized that acquaintance with manuscripts themselves is irreplaceable. A manuscript, said patristic scholar and Armenologist, Robert Pierce Casey, is “something between a gadget and a personality”. This is as true of manuscripts as paleographical evidence as it is of any other aspect of their use and value. The external technicalities of the manuscript may be learnt from pictures: the individuality of the scribe, even in technical matters such as thickness of pen, can be known best only from the examination of the manuscript itself.
Birdsall’s survey dates from a time not too distant, at least in terms of the slow-moving world of manuscript studies, but even so, the quality and the quantity of easily available, if not freely available, manuscript images online would probably have been inconceivable at the time of its writing. In other words, Birdsall, while acknowledging the value of often bitonal manuscript reproductions — if for no other reason than that that is sometimes all that was (and is!) available — seems to imply that one should always wish for a real, tactile encounter with “the manuscript itself”. This kind of autopsy today probably happens no more frequently than when Birdsall made the statement above, but it is likely that a great many more students and scholars have nevertheless seen manuscripts, and not bitonal images, but color photographs of such resolution that one might enlarge only a few lines and fill an entire screen without any loss of image quality. There are doubtless some things we miss when look at a manuscript on a screen, rather than on a library table — a notable one being an easily grasped perception of a manuscript’s actual size, something we can forget, even if we know the exact measurements, when reading on a screen and manipulating the size — but at least with very high quality digital reproduction, what do we lack that especially matters codicologically or paleographically speaking? Birdsall as an example mentions the thickness of the scribe’s pen. Is that still something “known best” only from immediate manuscript autopsy, is it something we cannot properly give attention to in digital manuscript facsimiles as available nowadays? On this question, see the image below and note the easily noticeable varieties of thickness as the scribe has turned the pen in different directions to form the letters.
If someone had access only to manuscript reproductions, even if bitonal and perhaps grainy, Birdsall, based the tone of his essay, would, I believe, encourage that person to go ahead and make the most of what they have. Those of us at work on manuscripts in various languages, not only Georgian, have the boon of much better images than were common fare even a couple of decades ago, and were he writing today, I wonder if Birdsall would have phrased his sentiments in quite the way as above.
 A.C. Harris, ed. The Indigenous Languages of the Caucasus, vol. 1, The Kartvelian Languages. Delmar, New York: Caravan Books, 1991. Pp. 85-128. It remains really the only thing of its kind in English. Unfortunately, it was published in a rather out-of-the-way book, not to mention the less than appealing typography.
 There is an obituary for Birdsall by J.K. Elliott from The Independent here.