Ghost line is an in situ installation that started in 2002 and is ongoing. The work, characterized by its great simplicity, consists of a line of ordinary pins stuck into a wall. At a certain time of day, depending on the position of the sun, the shadow cast by each pin will produce a continuous line and create an image. This ephemeral, almost magical alignment then splits into multiple directions. The line is a motif that literally traverses Ismaïl Bahri's work, from the drops of water moving along a sewing thread in Coulée douce (2007) to the lifelines on the artist's hand in Sondes (2017), and the spool unwinding over a snowy landscape in Dénouement (2011).

This work is very important to the artist because he considers it the origin of his current research. This Ghost line appears and disappears cyclically depending on the position of the sun in the sky. While the artist acknowledges that he did not create this mechanism, it fits for him "within the fold of the movement of the stars." With this immaterial line, subject to meteorological contingencies - clouds, night - the artist considers this drawing an "instrument that allows one to perceive a cosmic movement.