The Mysteries of Black: Absorption vs Reflection

When we paint something black, we are not actually taking away light from it. Instead, we are changing the way light interacts with that surface. This concept, often paradoxical, has intrigued artists and scientists for centuries. Let's delve into the fascinating world of black, where it is both the absence of all color and a mixture of all colors.

Absorption of Light

Black surfaces are famous for their ability to absorb a significant portion of the visible spectrum. When light strikes a black object, most of the wavelengths are absorbed rather than reflected back to our eyes. This absorption is so profound that we perceive the surface as having no color at all. Therefore, painting something black is not a simple process of removing light but a complex one of altering the interaction between light and the object.

Reflection

The act of reflection is crucial in understanding how we perceive color. When light hits a surface, some wavelengths are reflected, and the others are absorbed. For a surface to appear black, it must reflect very little light. In fact, black surfaces reflect as little as 3% of incident light, making them appear dark.

Perception of Color

Our perception of color is based on the light that is reflected off surfaces. When we look at an object, the light that it reflects enters our eyes and is interpreted as a specific color. Since black does not reflect much light, it appears as the absence of color. This is why objects painted black look dark to us. Painting something black changes its reflective properties, making it an absorber of light rather than a reflector of it.

The Paradox of Black and White

It's worth noting that black and white pose a distinct paradox in the world of light and color. Black is both an absence of all color (because it absorbs all light) and a mixture of all colors (thru its ability to absorb all wavelengths). Similarly, white is an absence of color (because it reflects all wavelengths) but is also a mixture of all colors (since it reflects all visible wavelengths).

Black pigments, for instance, are not truly black in the way that pure black light is. Instead, they are a mixture of other pigments that absorb a wide range of wavelengths. When mixed in sufficient quantities, these pigments can absorb most of the visible light, resulting in the perception of black. However, in reality, even the darkest black pigment will reflect a small amount of light.

White pigments, on the other hand, reflect all wavelengths of light, making them appear white. Similarly, white light is a combination of all colors. In practice, even a perfect white pigment will reflect a small amount of light and absorb the rest.

Painting in Black

When we paint something black, we are adding a substance, a pigment, that absorbs most of the visible light and reflects very little. This transformative action changes the reflective properties of the object, making it a high absorber and a poor reflector of light. This is why it appears black to our eyes.

To provoke further reflection, consider this: the average household mirror is only about 94% reflective. This means that during every reflection, roughly 6% of the light is absorbed. This small amount of absorption can significantly alter color perception and is a testament to the complex interplay of light and surfaces.