I was asked what the colours mean in my video showing this roll in my
editor.  These are fully explained in the notes accompanying the video
at https://www.youtube.com/watch?v=Lxt4ZdAg6G8  but for the record here
I said:

  "I don't like staring at a white screen with black dots, so the roll
  editor uses colours that are easier on the eye.  Also, they identify
  what the various punches are for.  Much easier to follow the
  expression coding that way!

  "You see roll perforations:
  Yellow - playing notes
  Blue - the expression (dynamic) coding (blue),
  Pink - sustain(left) and half-blow pedals (right).
  Red indicates punches that may be too close to the following one to
  trigger a repeat - a facility for roll editing.

  "The resulting bass and treble expression is shown as white lines
  that move out from the central stack split marker.  The upper dynamic
  limits are shown in grey.  Some Welte rolls contain printed expression
  lines laid out very much like this."

Julian Dyer