When light is incident at object. The light can either be absorbed, speculary reflected, or scattered. A green object, Absorbs all light apart from green, and then scatters green light in all directions. This green light then travels to my eye, and my brain processes it as a "green object". The light scattered from the green object that does not travel towards me, does not get registered by my brain, and therefore I will not see those rays. I hope everything upto this point is clear. You talk about "mixing light rays" and then draw a diagram of those rays and then I presume you think that we see those rays? We do not. **We do not see light that doesn't directly travel from the source to the eye in straight lines**. Light rays do not interact with eachother. The reason that the "entire room" is lit up, is because the rays that do not directly enter our eye, are incident on something like a wall. The rays from that green object that miss our eyes, instead reach the Wall, get absorbed and remitted by the molecules the wall. The light from the wall gets scattered in all directions, the rays from the wall that don't travel directly to our eye We don't see. The rays from the wall that DO travel directly to our eyes, we do see. The light from the wall is registered by our brains as what ever colour the wall happens to be. Ofcourse the light directly from the torch ALSO gets directly scattered by the wall aswell (along with the light scattered off the green object) This is also a reason why if you put a green object close to a wall, the wall appears slightly greener. The light from the green object is scattered by the wall, so that our brains register the wall having a greener tint to it. As there is more greenlight that is now scattered, in addition to the variety of light scattered by the torch. [![enter image description here][1]][1] For simplicity I have only added a single point of scattering Here we have white light that is incident an object. When it hits the object, light scatters in ALL directions. The light the enters the eye, is the ONLY light that I see. no mention of "the light ray that doesnt enter acts as another source that propagates to the eye," this is wrong. So as of now, if I were the eye, I would register the only light I see, is a green object(or a single point of green as I have only included a single point of scattering), and the rest of my vision is black. This is similar to the sun in space. In space everything is black, apart from the point at which the sun is, as the rays from the sun move in straight lines towards my eyes. Now what If we add walls? [![enter image description here][2]][2] [1]: https://i.sstatic.net/UcN2d.jpg [2]: https://i.sstatic.net/YTgiK.jpg For simplicity I have only added a single reflected Ray from the green object. The light that doesn't initially reach my eye, gets scattered by the wall in all directions!, the light that doesn't get scattered in my direction, I don't see, the light that does get scattered in my direction, I do see. (*Including all of the scattering elements from the wall and not just a single one*) From this POV, you should technically see a green wall as green light is all that is scattered. However in the diagram I have drawn blue. This is because the white light from the torch is also scattered by the wall, which I have chosen is predominantly blue that is scattered. However in reality, it should be blue + a tint of green. I hope this clears it up. In general, white light enters an object, only part of that light is scattered, giving it a specific colour, the light that is scattered directly towards you , you see, and your brain registers it as a coloured object. No extra sources required, light rays don't produce new light rays. Huygens principle is what is confusing you I'm pretty sure. This is already accounted for in the fact that you consider the net EM wave propagating and not a single element, these cancel out the apparent "source" of light from a direction not travelling straight toward you