First off, the light beams: These occur naturally, but only when there is some sort of particulate in the air. You only perceive light if it hits something, so in order to see a beam of light, there must be some sort of dust or water vapor or other gas in the air for it to bounce off of. Otherwise it is invisible to you. Now, the more dense the concentration of particulate, the brighter and more defined the beam will be... TO A POINT. If there is too much particulate, it will scatter the light and wash out your field of vision. Walk outside during an early morning heavy fog, and you will see this effect. Or turn on the high beams in a car in a misty area. It will literally make it impossible to see anything beyond the vapor in the air.
So, I would say as far as using beams in your art, they can be used to affect the mood of a piece, but keep in mind that using them will give the piece a sense of heaviness in the air, as well as allowing you to draw focus to something. ie: in your forest piece there, the beams draw my attention to the opening in the rock face, but also give the impression that the area is very humid (which, judging by the look of the foliage, it is. Good work
), or very dirty (lots of pollen in the air, although if there was enough there to effect beams like that you wouldn't be able to breathe 
). I also get the impression that the scene takes place early in the day, because that is the time that moisture tends to "burn off" of evaporate into the air.
For the room, a light beam coming through the window would definitely give the impression of a lot of dust hanging in the air, but it would also be a little harsh to look at if it was too bright and may wash out important details behind it. In some cases it can make a room look smaller too.
Bounce light is just that: light that bounces. Objects reflect their color and absorb other light, so any light being reflected off of an object will be the same color as the reflecting object. You also have to take the object's surface into account. A rough surface will diffuse the light to the point that it will be negligible, but a shiny or smooth object may actually reflect a great deal of light. The reflected light will lose some of it's intensity, however, so no reflected light will ever be as strong as the initial light source unless it's reflecting off of a mirror.
Loominus just posted an EXCELLENT tutorial about light in one of Hillbilly's threads in the CL, so take a look. It's good stuff.
So, I would say as far as using beams in your art, they can be used to affect the mood of a piece, but keep in mind that using them will give the piece a sense of heaviness in the air, as well as allowing you to draw focus to something. ie: in your forest piece there, the beams draw my attention to the opening in the rock face, but also give the impression that the area is very humid (which, judging by the look of the foliage, it is. Good work
), or very dirty (lots of pollen in the air, although if there was enough there to effect beams like that you wouldn't be able to breathe ). I also get the impression that the scene takes place early in the day, because that is the time that moisture tends to "burn off" of evaporate into the air.For the room, a light beam coming through the window would definitely give the impression of a lot of dust hanging in the air, but it would also be a little harsh to look at if it was too bright and may wash out important details behind it. In some cases it can make a room look smaller too.
Bounce light is just that: light that bounces. Objects reflect their color and absorb other light, so any light being reflected off of an object will be the same color as the reflecting object. You also have to take the object's surface into account. A rough surface will diffuse the light to the point that it will be negligible, but a shiny or smooth object may actually reflect a great deal of light. The reflected light will lose some of it's intensity, however, so no reflected light will ever be as strong as the initial light source unless it's reflecting off of a mirror.
Loominus just posted an EXCELLENT tutorial about light in one of Hillbilly's threads in the CL, so take a look. It's good stuff.
