Final answer:
The central panel of the Portinari Altarpiece by Hugo van der Goes includes the triptych format, oil paint, and wood canvas but does not use the troupe l'oeil illusion.
Step-by-step explanation:
When examining the central panel of the Portinari Altarpiece by Hugo van der Goes, we can find that it utilizes several key elements except one. The artwork indeed employs the triptych format, which refers to a work of art that is divided into three sections, or panels, that are usually hin_ged together and can fold shut. This design is common in Christian altarpieces from the Middle Ages and Renaissance. The central panel of van der Goes's altarpiece is also created using oil paint, a medium known for its versatility and the rich, deep colors it can produce. Additionally, it's painted on a wood canvas, which was a typical surface for paintings during the time.
However, the one element it does not use is the troupe l'oeil illusion, which is a French term meaning "deceive the eye." This technique is designed to create the optical illusion that depicted objects exist in three dimensions. The central panel of the Portinari Altarpiece, while rich in detail and symbolism, does not primarily aim to deceive the eye into seeing depth where there is none beyond the natural illusion created by perspective in painting.