An extended comment by Guy Etchells to my recent post on What is an Original? pointed out some additional issues with original documents vs. copies. Sometimes there is considerable confusion between the copy and the original. My comments were directed primarily to photocopies made in the last 30 or 40 years. However, there is a substantial historical issue with copies. In many cases, what we consider to be original documents, are in fact copies of copies and far removed from the original.
A good example of the issue of original vs. copy is the document we call the Declaration of Independence. One detailed history of the development of the manuscript that became finally accepted as the Declaration of Independence is found in "The Charters of Freedom" of the U.S. National Archives. The document displayed at the National Archives building in Washington, D.C. is a copy of the documents orginally printed for distribution to the Colonies.
Prior to the development of photographic reproduction processes, a copy of a document usually meant that the entire document was re-created using the original as a pattern. There is no doubt that variations will exist between the "original" and the copy made from the original. In examining older records, such as parish registers, wills, probate files and other types of documents, it is imperative to determine if the document you are examining is truly the original. There is a sometimes unfounded assumption that the "original" is more reliable than any copy. Unfortunately, the original records are not always accurate and subsequent copies may contain significant corrections to the content of the original.
The fact that you are looking at a copy of a document rather than the original may not always be readily apparent. Some copies are, in fact, more legible and easier to read than the original. Modern photographic techniques can enhance the quality of old documents and render visible portions of the document that may have faded with time or even been erased from the original.
My point, in my original comments, were concerning the dramatic shift in the legality of using copies for proof in court as opposed to the historical need to produce the original documents. The concerns about producing the original in court have dwindled to only very narrow areas of the law concerning probate of wills and other such formal transactions. Depending on the nature of the document, I have had the ability using high resolution scanners and photo editing programs such as Adobe Photoshop to reproduce a document so faithfully that you would need an expert to tell the original from the copy.
Further unfortunately, if the copies of documents are used for improper or illegal purposes, making a copy of an original for improper or illegal use is called forgery and is a criminal act. One time, years ago, when I was heavily involved in our graphic design business, we were contacted by the news media concerning doing a demonstration of how documents could be copied using the then existing technology. My partner showed the reporter how an almost undetectable copy could be made using the scanners and programs we had at the time.
As a note, the equipment I have today is a quantum leap ahead of what was available just a few years ago. As I have found recently, my high resolution digital camera now creates images far superior to a flatbed scanner.
Fortunately, in the realm of genealogy, we don't always need absolutely detailed high-resolution copies of all of the documents we examine. Sometimes a low resolution photo by a smartphone camera is enough to preserve the information.
There is yet still another issue concerning the need to preserve the original document (book, manuscript etc) if a copy has been made. In some cases, as with routine business records, it may not be necessary or even practical to keep the paper copies. In other circumstances, where the original may have some historic or sentimental value, keeping the original is mandated.
I am sure there is a lot more to say on this subject, for example what of the situation where there are multiple conflicting copies of the same document?