I'm using a film projector as an editor, meaning I run the film slowly and use a low power bulb. I want to minimise any possibility of damaging the films. To view a film I simply look straight into the lens – and I see an inverted image. What I can't explain is why the projected image appears the right way up. So, sitting in front of the projector: • I can see the frames entering the gate are upside down • Looking through the lens the image is upside down • But replace my eye with paper, and the image is right-way up. Why does light that strikes paper cause the image to appear one way, yet when it strikes my eye it appears the other way?