Why did the sky appear dark gray when taking black-and-white photos and using orange lenses in the past?

We know that the sky is blue when the sky is clear, and the orange color filter just absorbs blue light and lets red light pass through, so the black-and-white photos taken show a dark gray effect, because the blue light is absorbed, and the sky part displayed on the negative film is not exposed much. In this case, the level of white clouds is very good, especially in the plateau.