I recently purchased a copy of Hal Leonard's book "The Beatles:Please Please Me" (Guitar Recorded Version). Several of the songs in the book have the note "Recording sounds 1/4 step sharp". I know how to raise a guitar's strings a half or a whole step with a capo, but how do you raise them 1/4 step? (I've been told the recordings were raised 1/4 step by increasing the speed of the original recordings.) Also, my guitar is a budget acoustic with nylon strings. Will raising the strings 1/4 step damage the neck or break the strings?
It certainly wont hurt the guitar to tune up a quarter step. Using a digital tuner, you can adjust it so it gives the correct reading, and tune each string accordingly. Or, do as I did in the '60s, listen to a track and adjust on the fly, so the guitar is actually in tune to the track by ear. Takes a bit of practice, but it's a skill that will be useful when the tuner isn't available.
Yes, sometimes the track speed was changed when the recording was complete, but other bands, particularly purely guitar based bands, would all tune to the one guitar which was closest to 'in tune', meaning some tracks are out by that small amount ('in the cracks'), that just playing a concert pitch tuned guitar a fret up or down still won't work.
Tuning up a quarter-tone shouldn't hurt a guitar, but I'm giving no guarantee! Probably more sensible to run the recordings through an audio editor and bring them down to pitch without affecting the speed. We can do that now, they couldn't in the 60s.