The crescendo pedal, similar in appearance to a swell pedal, brings on stops progressively as the pedal is opened (ie moved towards the horizontal). This is mainly of use for orchestral playing or to provide accents to the music by adding stops quickly. It is best used judiciously.
Crescendo pedals may be provided with the means to set (or program) which stops are brought on; this can be useful to match the organist's style of playing.
By convention, the crescendo pedal is located to the extreme right of the group of swell pedals. It may be provided with an indicator lamp to show when it is in operation.
See further.
Crescendo pedal