Yes, tempera paint contains ingredients and pigments that naturally fade over time. Some of the ingredients required to make paint waterproof or fade-resistant have the downside of being toxic. So, the advantage of low toxicity in tempera paint comes with the tradeoff of fading over time. However, notice that not all tempera paint types will fade over time. Some tempera paint formulations, such as the egg tempera, are relatively durable and will resist fading over time.