Prebuilt RGB Working/Display Color Spaces

These objects are color space descriptors used by rayimage to tag images and to convert between RGB spaces. Each descriptor is a named list with:

• name: Character. Human-readable name of the space.

• primaries: List with r, g, b entries giving xy chromaticities.

• rgb_to_xyz: 3x3 numeric matrix (linear RGB -> CIE XYZ, Y=1 white).

• xyz_to_rgb: 3x3 numeric matrix (CIE XYZ -> linear RGB).

• white_xyz: Length-3 numeric XYZ of the reference white (normalized s.t. Y = 1).

• white_name: Character label for the white (e.g., "D60", "D65").

These are used as:

• attr(img, "colorspace"): the current working/display space for an image.

• attr(img, "white_current"): the current assumed scene/display white (XYZ, Y=1).

CS_ACESCG

CS_SRGB

CS_P3D65

CS_BT2020

CS_ADOBE

Details

Prebuilt RGB Working/Display Color Spaces

• CS_ACESCG: ACEScg (AP1 primaries, D60, scene-linear). Recommended working space.

• CS_SRGB: sRGB/Rec.709 (D65). Typical display space; used for PNG/JPEG/TIFF output.

• CS_P3D65: Display P3 (D65). Wide-gamut display space.

• CS_BT2020: BT.2020 (D65). Very wide-gamut; common for HDR mastering.

• CS_ADOBE: Adobe RGB (D65). Photo workflows.

See also

• render_convert_colorspace() to convert images between spaces.

• render_white_balance() for Bradford CAT within a working space.

• plot_image(), ray_write_image() for display/output conversion.

Examples

  # Tag a raw array as sRGB, then convert to ACEScg:
  arr = array(runif(64*64*4), dim = c(64, 64, 4))
  ri  = ray_read_image(arr, assume_colorspace = CS_SRGB, assume_white = CS_SRGB$white_xyz)
  riA = render_convert_colorspace(ri, to_mats = CS_ACESCG)
  plot_image(riA) # display-converted to sRGB automatically


  # Convert an sRGB JPEG to ACEScg on ingest:
  # img = ray_read_image("photo.jpg", normalize = FALSE)
  # img_aces = render_convert_colorspace(img, to_mats = CS_ACESCG)