C5 L2

Combining information from three cone types (red, green, blue) creates a vast array of colors.
James Maxwell developed a color matching technique still in use today for color generation through the combination of these cone types or light filters.
- Example: To generate light blue, different amounts of blue, green, and red filters are combined.
- This technique allows for matching requested colors through adjusting light mixtures.
- This methodology relates to psychophysics, referred to as the method of adjustment.

Defined as combining different amounts of light.
If light A (e.g., blue) and light B (e.g., green and red) are reflected together to the eye, their effects add together.
- Example: Blue light combined with equal intensity red light creates yellow.
- All three primary colors (red, green, blue) combined result in white light.

This process involves color pigments or paints instead of light.
Example: Mixing red and green pigments does not yield yellow but instead results in a dark brown color due to how pigments interact with light.
- Pigments reflect specific wavelengths while absorbing others, determining the color that is seen.
- When a surface pigment is illuminated, the light absorbed influences the perceived color.

Color filters (red, green, blue) selectively pass certain wavelengths while absorbing others.
- A yellow filter absorbs short wavelengths and lets longer wavelengths (yellow/oranges) pass through.
- Using a double filter (yellow followed by blue), only specific wavelengths are permitted through, thus revealing a green color after filtering.

Additive Color Mixing
- Color results are lighter.
- Primary colors (red, green, blue) create secondary colors (cyan, yellow, magenta) through combination:
- Green + Blue = Cyan
- Green + Red = Yellow
- Blue + Red = Magenta
Subtractive Color Mixing
- Results yield darker colors typical of pigments.
- Combination of pigments leads to secondary colors:
- Yellow + Magenta = Red
- Yellow + Cyan = Green
- Magenta + Cyan = Blue Violet
- Full mixing of cyan, magenta, and yellow pigments results in the darkest color—black.

Additive Color Model
- Combines primary colors to yield secondary colors and ultimately white light.
- Secondary colors are combinations of primary colors.
Subtractive Color Model
- Involves mixtures of primary pigments that lead to darker hues.
- When combined, secondary pigments yield increasingly darker colors toward black.

The brain combines information from the three cone types, resulting in specific color perception without directly calculating the inputs from L, M, and S cones.
Retinal Processing
- Simultaneously calculates outputs based on input from cones.
- For example, if L cone fires at 30 units and M cone at 40 units,
- Calculation: 30 + 40 - S cone (20 units) = 50 units.
Cone Opponent Cells
- Based on the differences between cones: various pairs create color perceptions via excitation and inhibition.
- Colors pairs include:
- Red/Green
- Blue/Yellow
- Black/White
Opponent Process
- Specific cone types have excitatory and inhibitory responses to different wavelengths, allowing for nuanced color discrimination.

Artists mimic additive color mixing using tiny dots of pigment rather than mixing paints directly. This technique allows for the visual merging of colors from a distance, creating lighter perceived hues when viewed from afar.
Cone Sensitivity & Light Perception
- Recent studies demonstrate differential responses of cones to white light versus specific wavelength stimuli. They suggest cones offer additional vision information beyond color, such as light intensity changes and perceived contrast.

Understanding the differences and methodologies behind additive and subtractive color mixing is vital for applications in art, design, and color theory. Hence, the principles of these mixing methods are fundamental for interpreting color in various contexts.