This is often called a "mirror" site, but it's more than that:
"Here's yet another index of the Digital Tradition Folk Music Database; you can read about the Digital Tradition at their main site at Mudcat. This version differs in that songs which have tunes have those tunes available as GIFs or PostScript scores. This version is currently using the Spring '02 version of the database. ... This site is completely unsupported. I maintain it for my private use; it is only publically available because it is easy to do so. You can try to contact me, but I can't promise an answer."
From the rest of the description, I infer that the publisher wrote some code to translate the midi files stored in the DT datbase into other formats.
Which is to say, requests for tunes not available as midi files in the Spring '02 (apparently the latest) version are futile at best, annoying (I suspect) at worst.
If you're a non-geek, or novice geek, printing pages from your browser may be the best way for you to quickly get hard copy to share with others, but you might want to drop by a copy center and enlarge the score portion (which is a low resolution image file) before passing it 'round.
The PostScript versions make nice crisp prints of just the scores. PostScript is a printer format (instructs a printer how to render a document) so you have to have a program that can interpret it.
I use GhostScript. It's free to obtain and use (GNU General Public License). You can preview PostScript files with it. I also sometimes use it to view Portable Document Format (.PDF) files, as it seems to load them quicker than Acrobat.
"Ghostscript is the name of a set of software that provides:
An interpreter for the PostScript (TM) language and the Adobe Portable Document Format (PDF -- sometimes confused with Acrobat, Adobe's PDF browser/editor product)
A set of C procedures (the Ghostscript library) that implement the graphics and filtering (data compression / decompression / conversion) capabilities that appear as primitive operations in the PostScript language and in PDF."
If you're comfortable with installing programs on your system, the cost of your time to download, configure, and get familiar with it will be steadily offset with each tune you print.
The score images and PostScript files are melodies only - no chords displayed above the lines. You may not need more than that if you can read key signatures. The PostScript files are all I need, so I haven't looked into the programs that read the other formats (ABC, SongWright, Lilypond) and can't tell you if those programs can render chords from the melodies.