Fundamental Principles of Light and Color Theory

Properties of Light and the Visible Spectrum

Light consists of multiple wavelengths. The visible spectrum contains wavelengths that are larger than those of X-rays but smaller than microwaves. White light includes all wavelengths of the visible spectrum. Within this spectrum, the red wavelength is less energetic than the violet wavelength. Generally, wavelengths beyond the visible spectrum have less energy than those within the spectrum.

Propagation and Behavior of Light

Light propagates in a straight line. When light interacts with objects, it can behave in several ways: it can be absorbed, transmitted, or reflected.

• A light ray incident on a red object reflects red wavelengths.
• A light beam incident perpendicularly on a smooth and opaque object is reflected back along the same path in the opposite direction.
• A light beam incident at an angle on a smooth and opaque object is totally reflected.
• When a light beam strikes an object, it may undergo a change in its rate of spread (speed).
• A light beam passing through red glass undergoes selective transmission, preferably passing the red wavelength.

Refraction and Light Intensity

When a light beam hits a surface of a different refractive index at a certain angle and passes through it, it undergoes a change in its direction and speed. Regarding light intensity, given two surfaces receiving light from the same source at different distances, the surface nearer to the source receives higher light intensity.

Optics and Lens Properties

Pinhole Imaging and Focal Distance

When we expand the size of the pinhole in a dark room, the resulting image becomes worse or blurrier. Conjugate distances are defined by the relationship between the subject distance, the lens, and the image distance.

The focal distance of a given objective is the distance between the lens and the sharp image when the object is at infinity. To focus on a closer object, a longer focal length or distance is required. Furthermore, lens convergence increases as the focal length becomes smaller.

Color Theory and Systems

Primary and Complementary Colors

The primary colors are red, green, and blue. The complementary colors are magenta, cyan, and yellow. In the color wheel, complementary colors are placed facing each primary color.

• Cool colors: Green, cyan, and blue.
• Warm colors: Red, magenta, and yellow.

Additive and Subtractive Color Mixing

In an additive system, mixing primary colors produces the following:

• Mixing blue and green results in cyan.
• Mixing red and blue results in magenta.
• Mixing red and green results in yellow.

In a subtractive system, colors are obtained by removing wavelengths from white light:

• White minus Red = Cyan
• White minus Green = Magenta
• White minus Blue = Yellow