I’ve been doing some study on Codex Sinaiticus and the claim that a document forger by the name of Constantine Simonidies produced the codex in 1840 as currently popularized by Chris Pinto in his documentary, Tares Among the Wheat. The question modern readers may wonder about is how exactly can experts distinguish between genuine, ancient manuscripts and recent forgeries? This is particularly important as it relates to identifying Codex Sinaiticus as a 4th century manuscript rather than a 19th century production. I came across an interesting paragraph found in a lengthy article addressing the whole Simonides affair in an old version of The Journal of Sacred Literature, available on line at Google books, that goes into some detail with answering that question.
“We cannot turn from this topic without a word for the encouragement of those who are not skilled in old Biblical manuscripts. They might say, if the ‘Codex Sinaiticus’ is by any possibility a modern production, the same may be true of other manuscripts which pass for the most ancient. Our friends may be reassured: there are features in these most venerable copies of the Holy Scriptures which cannot be imitated. A skilful man, by long practice, and with a certain knowledge of chemistry, could imitate the characters and appearance of many manuscripts on paper, and of some on vellum. But there is a limit to these things, and detection is almost inevitable. The action of ink upon vellum is peculiar, slow, and gradual, and leads to results which can be measured by time. The action of light and air, and warmth, and moisture, are also remarkably uniform. The style of writing peculiar to certain periods is commonly definable. The arrangement of all the parts of a manuscript is also, when taken in connexion [sic] with other phenomena, a clue of great value. Indeed, palseography [sic] and textual criticism together, enable men not only to fix often the country, and more often the date of a manuscript, but even the class and age of that from which it was copied. A manuscript at Sinai would not in a few years suffer much from wear and tear, nor even from sheer neglect, and the veriest tyro in such matters would never be deluded into the belief that a venerable uncial from that monastery was written in our time by even so skilful a hand as that of Simonides. Our readers will not be tempted to cast aside the results of modern science on the ipse dixit of any man. In the case under consideration it would be the height of folly.”