The Channel Remap (HSV) effect allows you to reassign your layer’s hue, saturation, value, and alpha channels. This effect gives you creative flexibility to manipulate color and transparency in a way that adjusts how each channel interacts, offering deeper control over your design’s look.

Key Features Channel Remap

Channel Remap (HSV) Effect
  1. H (Hue)
    Determines which input channel is used to control the hue of the output.
    Default: Hue
  2. S (Saturation)
    Defines which input channel is mapped to the saturation output, influencing color vibrancy.
    Default: Saturation
  3. V (Value)
    Controls which input channel determines the brightness (value) of the output.
    Default: Value
  4. A (Alpha)
    Determines which input channel is mapped to the alpha (opacity) channel of the layer.
    Default: Alpha

How It Works

The effect operates by first converting the RGB channels into the HSV (Hue, Saturation, Value) model, remapping them according to your adjustments, and then converting the output back to RGB for final display.

Each channel (H, S, V, A) can be assigned to one of the following input sources:

  • H: Uses the hue channel from the input layer.
  • S: Uses the saturation channel from the input layer.
  • V: Uses the value (brightness) channel from the input layer.
  • A: Uses the alpha (opacity) channel from the input layer.
  • Y: Uses the luminance channel, which accounts for human visual perception (more on this below).
  • 0: Uses the minimum value for the channel.
  • 1: Uses the maximum value for the channel.

Channel Remap Details

  • Hue: Represents the color’s position on the color wheel, starting from red. The values range from 0 (red) to 1 (back to red).
  • Saturation: Ranges from 0 (no saturation, producing grayscale) to 1 (full color saturation).
  • Value: Defines the brightness of the color, with 0 being black and 1 being the brightest possible color.
  • Alpha: Defines transparency, with 0 being fully transparent and 1 fully opaque. However, be cautious when using alpha values, as they can sometimes lead to unexpected results with transparency handling on different devices.

Weighted Y (Luminance)

The luminance value (Y) compensates for how the human eye perceives brightness. For example, green light appears brighter to the human eye than red or blue light of the same intensity. The effect uses this weighted formula to calculate luminance:

Y = (R * 0.2126) + (G * 0.7152) + (B * 0.0722)

Choosing Y for the value channel can help produce more visually natural results.

Alpha Handling

Be aware that setting the alpha channel to 1 in a layer that has transparent areas may cause issues, as fully transparent pixels may still have underlying RGB data. This could result in artifacts or unwanted visual effects. It’s recommended to only set alpha to 1 if you’re not working with RGB input channels for the alpha channel.

Common Use Cases

  • Alpha Masking: Create an alpha mask by setting S = 0, V = 1, and mapping Alpha to either S or V.
  • Rainbow Effects: For rainbow or color transitions, set V = 1, S = 1, and map H to S, V, or Y.
  • Luminance Mapping: Create grayscale luminance maps by setting S = 0 and V = H or S. These can be used with other effects that rely on luminance, like Displacement Map

See Also

See Also