The reason for the transparent nature of glass is that the photons of visible light don't have enough energy for the electrons of glass to absorb and jump to higher energy levels. As a result, the photons are able to pass through the material.
It's all good. Now let's consider this... Suppose there's an opaque material. Opaque to visible light. Now there's a fixed amount of that material. For example, a small plastic cube. It would have a certain number of electrons. Now, if light falls on it, the electrons will absorb the photons and the object will appear opaque. So far, so good. Now, suppose the intensity of light is increased. This would mean that the number of photons will be increased. But the plastic cube would still possess the same number of electrons as before. So my question is, would the extra photons be able to pass through the material and make it appear transparent or maybe translucent? I mean, the electrons will absorb some photons but since the intensity is increased, there will be a lot more extra photons to get through the material.
Now, what I've hypothesised above clearly doesn't happen.. or does it?? Lol. Anyways, I'm quite sure it doesn't. So I'd like to know the fault in my line of reasoning. I hope it's understandable.