In my darkroom, I've have to use the Beseller 4x5 enlarger to print by enlargement those 6x12cm negatives, as they can't be accomidated in the 23C enlarger. So, in this respect they're LF negatives; but I have to agree with most of the others that LF generally implies sheet film, not roll film. (Ignoring such exceptions as 9.5" aerial surveillance roll-film cameras, and using a MF back on a 4x5, etc.)

~Joe