I've been surprised to see in the past few days that the International Music Score Library Project is just now becoming news to many music bloggers. Since I'm pretty new to blogging, it wouldn't have occurred to me that this amazing resource wasn't already widely known among net-savvy musicians. It's been in my sidebar list of favorite free music resources since I moved in here, but then I've been snooping around for music scores online for years now.
Basically, there are two types of free scores to be found (legally, that is). The first would be scores of public domain music that have been notated in programs like Finale and Sibelius and posted online by the generous notators. I used to create a lot of my own editions in Finale for my church choir, and the enormous Choral Public Domain Library is evidence that I'm not the only one. Most of the standard choral repertoire is available there in editions that range wildly in quality. Although these scores are usually available in formats that can be furthered edited (transposed, for example) if you have the right software, they are almost always available in PDF format as well, so that pretty much anyone can print them out.
Oddly, the next wave of free online music featured the more old-fashioned approach of scanning public domain music and posting the files essentially as big pictures converted into PDFs. Because files created in notation programs are much "smarter," they can be converted into fairly small PDFs based on font information, etc.; the scanned files, which are necessarily much larger, didn't really catch on until the broadband revolution made them easily downloadable. To my knowledge, the first big scanned library was EveryNote.com which charges a buck or two for their scans. It's a strange, convenience-based business model; basically, you're paying them for having taken the time to track down old scores and run them through a scanner. Their pricing schemes are rather inconsistent - some decent bargains and some that are really overpriced. They also have some very poorly scanned files, although they've been good about refunds in such cases. I've used EveryNote.com several times when I needed music quickly, but it always struck me as a transitional business that couldn't last.
With the rapid, wiki-fed growth of IMSLP (also mostly scanned scores), more and more of the public domain standard rep is now available for free, surely to the chagrin of the EveryNote entrepreneurs. Whether free or not, it's important to remember that these public domain editions all date from the early 20th-century and before. There's a lot of variation in how much that matters depending on the music being considered, but these aren't state-of-the-art scores. It's also worth remembering that printing these scores involves ink/paper/time costs, so even free isn't necessarily free.
Still, I think Chris Foley is missing the point somewhat in his comparison of these free files with published sheet music; I don't see them as competitors, but I use IMSLP and other such sources extensively for three main purposes: 1) general reference, 2) class lectures, and 3) emergency situations. As an example of reference use, I've been grading music history (Classical Era) papers these past few days; most of the papers involve some sort of musical analysis, so time and again I've gone straight to either IMSLP or the Mozart Edition Online to check the score. (The Mozart edition is quite cool, of course, but not all that user-friendly. Following my link will save you significant time over going to their home page.)
As for class lectures, I use these resources all the time. It's so much easier than dealing with making transparencies or even using one of those fancy document cameras. I haven't yet used a tool like PDF Annotator, but I expect to add that to my teaching arsenal soon. Even without annotations, it's great to have, say, the full score of Beethoven's 5th so conveniently referenced from a laptop; one can zip around within the score or to other scores with such ease. I've also found free public domain scores useful in many other teaching situations. For example, they provided an easy and legal source of photocopiable songs for my Spring semester German diction class.
Emergencies? Well, they do happen. My department chair, music director at a big local church, was fretting three days before Easter that he was missing his trumpet parts for the "Hallelujah" chorus. I popped online and had them printed out for him in less than ten minutes. I've had many other occasions where it saved me significant time to get my music online. This has nothing to do with replacing the scores on my shelf.
My eyebrows also went up reading this from Foley: "Unless you're a paper-binding specialist, the binder you store your [printed-from-online] scores in won't be as reliable or attractive as a published score, and the three-hole-punched pages won't stay in as firmly as they do in a printed score." Actually, many published scores are a nightmare to keep open, whereas double-sided pages in a binder are easy to manage, and a simple black folder is perfectly attractive. Binding one's own pages in a three-hole notebook also allows for taking page-turns into account, something that many published scores do poorly. In some cases where I know the music well, I've used PDF files to print four reduced-size pages per page as a way of virtually eliminating turns.
In fact, I find many new editions to be much less carefully laid out than some of those ancient, public domain jobs. It's remarkable to see how painstakingly typeset many of the old editions were, whereas current editions are often the products of carelessly used software. Although notation software like Finale can yield fantastic results, it still requires a kind of care and attention that is often lacking. This seems like a good subject for another day, though. I've still got lots of grading to get through . . .