The ghostbusters elbow pads are modified volleyball kneepads that are worn over the sleeves of the flightsuit on the elbows. The elbow pads should have 3 “bubbles” on the back of them and be grey in colour. Most volleyball pads that are made these days are either black or white so spraying them with primer or dyeing them works well. On the Ghostbusters 1 pads, black squares are on the crease of the elbow. Defender Kneepads, Century Kneepads and Cannon Sport Kneepads are all very accurate to what was seen on screen.
Venkman’s elbow pads, notice the black square in the crease of each elbow. Also the bubble of the elbow pads are surrounded in black too.