Blending modes in Photoshop CC determine how the pixels on one layer interact with pixels on lower layers and how painting tools interact with pixels already present on the active layer and layers below.

• Normal: Normal is the default blending mode for new layers and the basic painting tools. Depending on opacity, the upper pixel completely blocks the lower pixel.
• Threshold: When working with images in Indexed Color or Bitmap color modes, Threshold is the “Normal” blending mode. Because Indexed Color uses a maximum of 256 distinct color and Bitmap uses only black and white, most blending modes are not available when working in those color modes.
• Dissolve: Only semi-transparent pixels produce changes in the image’s appearance. Those pixels are randomly scattered, producing rough edges on anti-aliased artwork.
• Darken: The Darken blending mode compares the individual color component channels (RGB or CMYK) of the base and blend colors and retains the lower value (RGB) or higher value (CMYK). It works on each channel individually for each pixel.
• Multiply: The Multiply blending mode multiples the color values of each base and blend pixel (RGB or CMYK) and uses the resulting value, which is always darker unless blending with black.
• Color Burn: Color Burn simulates the darkroom technique used to darken areas of a photo by increasing exposure time for that area. Blending dark colors over a base color produces a darker resulting color. Color Burn generally increases contrast. White as a blend color produces no change.
• Linear Burn: Like Color Burn, Linear Burn generally darkens (except where the base color is white). Linear Burn decreases brightness rather than increasing contrast.
• Darker Color: While the Darken blending mode looks at the luminosity of each pixel channel-by-channel, Darker Color looks at the overall luminosity of the base and blend pixels and retains whichever is darker. It generally produces less of a color shift than does Darken.
• Lighten: The Lighten blending mode compares the individual color component channels (RGB or CMYK) of the base and blend colors and retains the higher value (RGB) or lower value (CMYK). It works on each channel individually for each pixel.
• Screen: Screen is the mathematical opposite of the Multiply blending mode. The inverse of each pixels’ color value is multiplied. The resulting color is lighter than the base color.
• Color Dodge: The opposite of Color Burn, the Color Dodge simulates the darkroom technique of lightening areas of a photo by reducing the exposure time. It’s much like Photoshop’s Dodge tool, but generally results in both lighter and less saturated result colors.
• Linear Dodge (Add): The base color is lightened to reflect the blend color. Blending with black produces no change.
• Lighter Color: While the Lighten blending mode looks at the luminosity of each pixel channel-by-channel, Lighter Color looks at the overall luminosity of the base and blend pixels and retains whichever is lighter. It generally produces less of a color shift than does Lighten.
• Overlay: Consider Overlay to be a mix of the Multiply and Screen blending modes. If the blend colors are light, it works like Screen and if the blend pixels are dark, it works like Multiply. Overlay often produces a shift in hue as well as brightness.
• Soft Light: Soft Light combines the effects of Color Dodge and Color Burn. If the blend color is light, the result is lighter; if the blend color is dark, the result is darkened. Soft Light is often a more subtle option to Overlay.
• Hard Light: Hard Light is a more vivid version of Soft Light. Darker areas on the blend layer produce darker result colors; lighter areas on the blend layer produce lighter result colors. Painting with dark and light shades of gray on a layer set to Hard Light can be an effective way to increase contrast in specific areas of an image.
• Vivid Light: Vivid Light is much like Overlay in that it both darkens and lightens, but it also generally increases saturation significantly.
• Linear Light: The Linear Light blending mode works much like Vivid Light and can be considered a mix of Linear Dodge and Linear Burn. Lighter blend pixels produce lighter result colors; darker blend pixels produce darker results. Linear Light works with brightness values, which can better protect hue in the resulting colors than can Vivid Light.
• Pin Light: Pin Light combines the Darken and Lighten blending modes. Where blend colors are darker than the base color, they are retained, but if the base color is darker, it’s retained. When working with light blend pixels, the lighter of the blend and base colors is retained.
• Hard Mix: The Hard Mix blending mode produces a posterizing effect by forcing similar colors to a single value. When working with RGB images, the channel values for blend and base colors are added. Any value over 255 is set to 255, if less than 255, the value is set to 0.
• Each channel value is calculated individually for each pixel. The result is an image that consists entirely of black, white, red, green, blue, cyan, magenta, and yellow pixels.
• Difference: The Difference blending mode compares the brightness of the blend and base colors and the lower value is subtracted from the other. Black produces no change, while white will invert the pixel’s color.
• Exclusion: Exclusion is a less dramatic version of Difference.
• Subtract: Subtract compares the base and blend values in each channel for each pixel and subtracts the blend value from the base value, generally resulting in a darker image with substantial color shifts.
• Divide: The blend color is divided by the base color, channel by channel, for each pixel. It generally produces a much lighter result color.
• Hue: This blending mode retains the luminosity (brightness) and saturation values of the base color and substitutes the hue value of the blend color.
• Saturation: The base color’s luminosity and hue are retained and the blend color’s saturation value is used.
• Color: The base color’s luminosity is retained, and both the hue and saturation of the blend color are applied.
• Luminosity: The base color’s hue and saturation are retained, and the blend color’s luminosity is used.
• Behind: Used by painting tools, this blending mode applies the foreground color to pixels on the active layer according to the pixels’ transparency. Completely opaque pixels are not changed. (With gray, this blending mode can be used to paint shadows “behind” artwork on the layer.)
• Clear: Used with painting tools and shape tools set to add pixels to a layer, this blending mode works much like the Eraser tool, reducing the opacity of pixels on a layer.
• Replace: (Spot Healing Brush and Healing Brush only) This blending mode is used to help preserve texture along the edges of the brush strokes.
• Pass Through: (Layer groups only) Any adjustment layer within the group is applied to all layers below it within the group and below the group. (To restrict an adjustment layer to only the layers below it within the group, change the group’s blending mode from Pass Through to Normal.)
• Add and Subtract for Calculations and Apply Image: The RGB value of each channel is added or subtracted and the Scale factor (1.0 to 2.0) is used as a divisor. (A Scale value of 2 averages the channel values.) An offset factor can be added as a constant applied to or subtracted from each calculation.