My statement is correct. Your statement is also correct. I’m describing it from the perspective of the person viewing the movie. I did not say the color was blocked; I said it was filtered out. The red filter does pass red colors, but the red is invisible to the user. Colors are either passed or absorbed by the red filter. If the color is passed, the color red is added to the original color. Colors that are absorbed are blocked and become dark because they do not pass through the filter.

Try it yourself. If you mark a white piece of paper with a red ink marker and view it through a red filter, you will not see the red mark. The red mark was passed through the filter, but the color red was added to the white paper and they therefore blend together. Hence, from the viewer’s perspective the red mark is filtered out of the image. If the red color was being blocked or absorbed by the filter, it would appear very dark or black.