Bad Strings

[javert]

Last week I decided that it was time to change the strings on my Kelly and oil the fretboard. After putting on the new strings, I played for a while but I struggled with the tuning turning the tuners incessantly. I turned on the tuner, and it appeared that the intonation was way off. In the 12th fret, the notes were 1/4-1/2 tone off on the three high strings (E, B, G). I though that it was due to the changing of the seasons, so I started adjusting the intonation, but the interval was too small to compensate for the large deviations. For a while, I was really worried that the changing temperature and humidity had ruined the neck or something. Then I tried changing one of the strings. I had encountered individual bad strings in the past, but the thought that multiple strings in the same set could be bad seemed unlikely. Turned out they were! As you can probably imagine, I was quite relieved...

Regards,
Mads

Oh, and for no particular reason here's the guitar in question: