It will look black, or green, depending on the hue of the red. A green filter blocks the red light but no red object is reflecting solely in the red wavelengths, and any non-red light will appear green through the filter.
green
A green object appears black when viewed through a red filter (here a red filter means red light) because green object can only reflect green color and absorb all the other colors so in the red light it will definitely appear black.
What is true is that the light has a green component. That's why it appears green. The green light can get through. There may have been another or other colors of light present when the light entered the filter, but because the filter is green, the other colors were absorbed. Remember, if an object is a given color, it is that color because it reflects that color and absorbs all others.
I'm guessing it was probably the GREEN light, and that somehow it had something to do with why the filter was named a "GREEN" filter, and why when you looked at it, it looked GREEN.
Since an object is observed as the color(s) it reflects, a green object absorbs all colors and reflects green.
green
green
A green object appears black when viewed through a red filter (here a red filter means red light) because green object can only reflect green color and absorb all the other colors so in the red light it will definitely appear black.
What is true is that the light has a green component. That's why it appears green. The green light can get through. There may have been another or other colors of light present when the light entered the filter, but because the filter is green, the other colors were absorbed. Remember, if an object is a given color, it is that color because it reflects that color and absorbs all others.
A coloured fliter works by only allowing a certain section of the spectrum through the fliter. For example, if everything seen through a filter is green hued, then the filter only lets through green light.
red apples
When a yellow book is viewed through a green filter, the filter will absorb most of the yellow light but allow green light to pass through. As a result, the book may appear darker and its yellow color may become less vibrant when viewed through the green filter.
I'm guessing it was probably the GREEN light, and that somehow it had something to do with why the filter was named a "GREEN" filter, and why when you looked at it, it looked GREEN.
green
Since an object is observed as the color(s) it reflects, a green object absorbs all colors and reflects green.
Since an object is observed as the color(s) it reflects, a green object absorbs all colors and reflects green.
A filter removes certain colors of light which pass through it. The primary colors of light are green red blue. Since the shirt absorbs all but blue light and the filter removes all but green it will appear black.