Drawing is much more complicated than many people think. It also has a lot to do with physics. The main physics behind drawing is light waves. This is because light is a type of wave, which carries energy like all other waves. Light is essential for drawing, or any other kind of art. Light allows you to see, and more specifically, it allows you to see an object’s shape, color and the shadows on it. Being able to see all these things makes it possible to take a 3D object and put it on a piece of paper.
The way light lets you to see objects and colors is by reflection. White light is where all the colors in the spectrum of visible light appear all at once. Examples of this is the sun.
These pictures show each color's wavelength. Red has a long wavelength, violet has a small shorter one. All of them together are white light.
Different objects reflect a specific color, or type of light because of their different wavelengths. Space is the only true black because it absorbs all light and colors because there is nothing for light to reflect off of. An example of light reflection creating colors is an apple. When you look at it, you see it as the color red. This is because red light is reflected off of the apple and into receptors in your eye, and all the other colors are absorbed into the apple.
So, when you are trying to draw or paint, or whatever else, you have to look at an object and observe its light. This object reflects light and creates color. But there are also shadows. Rounded objects allow light to diffract. Light waves want to travel in straight lines, but when they run into an object, they diffract, or bend slightly around the edge. This makes your eye see the object get gradually darker until there is barely any light reaching it, on the side facing away from the light waves.
This is why it’s difficult to accurately draw things unless you know how to look at the light instead of just the object itself. Looking for the light and dark spots of the object is what makes it look 3D on paper. I have always wondered why it seems so hard to draw, but now I know its because I’ve just been looking at the shapes instead of paying more attention to the light on it. I’ll have to keep that in mind.