Side blackening of the piano keys

This article is intended for piano technicians

To prevent the IR light from scattering, the instrument keys must be colored on their sides with black permanent marker.

  • In practice, it has been shown in many cases that both “white keys” and the (already) black keys should be (additionally) colored (i.e., painted over) on the sides.

The paint usually used to color the black keys often contains metallic particles (glossy / matte-glossy). Thus, such a coating has a counterproductive effect.

We recommend the product edding 850 permanent marker black for blackening the keys. Also suitable is the (widely used) product edding 8750 industrial paint marker black.

However, the 850 model is suitable because of its wide tip (15 mm) to work faster.

The key must only be blackened from the side (i.e. not from the underside). Make sure that the blackening reaches all the way to the bottom edge.

  • In practice, an area of only 1-2 mm not covered with edding has already proven to be problematic (depending on the black paint originally used, which, as mentioned above, may contain reflective particles).

The entire process takes about 12-15 minutes during installation and should therefore be planned accordingly.

If the light from an IR transmitter is scattered too much, reflections can also occur from neighboring keys. These can negatively affect detection and subsequent digital processing.

  • In practice, this can lead to losses in the translation of the dynamics. This results (when using piano samples) in a “muffled” sound impression when one or more adjacent keys are played.

Here is an example:

  • An F is played (white key). The digitally generated dynamic range is normal.
  • If one (or both) adjacent keys (E and F#) are pressed at the same time, the dynamic range that can be achieved with the F key is significantly reduced.
  • This effect is visible (via the bar display of the VARIO app; aka MIDI velocity).
  • The effect is usually also audible (the resulting MIDI velocity is approx. 15 to 20% below the regular value.