Summary
Highlights
For precise color specification, systems like Hue, Saturation, and Luminance are used. Hue refers to the color name (e.g., red, green), saturation is the color's vividness or purity, and luminance is its brightness. These parameters allow for exact color definition, important for various industries.
This video is the first in a series about color vision, focusing on basic color concepts. The series will cover color science, the reception of color by the retina, and the perception of color by the brain. Color can be understood technically as electromagnetic waves detected by the eye and interpreted by the brain, or appreciated for the richness it adds to visual perception.
Colors originate from nature, like spectral colors in a rainbow, or are created by mixing other colors through addition (light) or subtraction (paint). Understanding color basics is crucial for comprehending color vision. Isaac Newton's 1700 experiment with a prism revealed that pure white sunlight contains a full spectrum of colors, and these colors can be recombined back into white light.
Additive color mixing involves combining lights of different colors. Examples using three colored lights (red, green, blue) demonstrate that red and blue make magenta, green and blue make cyan, and red and green make yellow. All three colors together produce white light.
The Paint program (or similar graphics software) can be used to experiment with color mixing. The 'Define Custom Colors' feature allows users to manipulate colors using either Hue, Saturation, and Luminance (HSL) or Red, Green, and Blue (RGB) systems. By adjusting RGB values, one can observe additive color mixing, where all three colors at maximum (255) create white, and at zero create black.
Red, green, and blue are common primary colors in additive mixing, used in devices like TVs and monitors. Cyan, magenta, and yellow are subtractive primaries. Complementary colors, opposite each other on the color wheel (e.g., blue and yellow, red and cyan), produce white when combined in additive mixing. This can be demonstrated by inverting colors in a paint program.
Subtractive color mixing occurs when specific wavelengths are removed from white light, as with colored filters or paint. A red filter blocks blue and green light, letting only red through. Similarly, paint pigments absorb certain wavelengths and reflect others; for instance, yellow paint absorbs blue light and reflects red and green, which our eyes perceive as yellow. This explains the difference in color creation between addition and subtraction.
Color matching is central to how our color vision works, as the retina's cones combine inputs. Any spectral color can be matched by a combination of red, green, and blue light. For example, spectral yellow (580 nm) can be matched by combining red and green light. The eye cannot distinguish between pure spectral yellow and yellow created by mixing red and green, even though their spectral compositions differ. These are called metameric colors.
This video introduced additive and subtractive color creation. Light uses additive mechanisms (e.g., sunlight containing all colors appearing white), while paint and filters use subtractive mechanisms. These concepts are foundational for understanding color sensing and processing by the retina, which will be covered in the next video focusing on color matching.