Ocean 2015 – Colorimetry

Ocean 2015 – Colorimetry

Ocean 2015 has several new groundbreaking features for working with colors

The XYZ color picker with its generated metamer outside the RGB gamut
The XYZ color picker with its generated metamer outside the RGB gamut

XYZ color input

It is now possible to set a material color to XYZ instead of RGB. This feature exists in other renderers, but implementations always suffer from either of these drawbacks:

  • The XYZ value is converted to RGB and thus is always clipped to a limited gamut
  • The renderer works in XYZ color space, which is incorrect : multiplying a XYZ intensity value by a XYZ material reflectance may lead to impossible colors that are outside the CIE XYZ domain.

Ocean 2015 is full spectral, XYZ input values are first converted to a spectrum by generating metamer. This is the most accurate way of handling XYZ input data in light simulations.

The XYZ metamer generator has the following properties :

  • Accuracy : the generated spectrum has the requested color coordinates with at least four digits after the decimal dot for x and y.
  • Continuity : similar XYZ values generate similar spectra
  • Plausibility : the generated spectrum has a natural shape

XYZ source images

In addition, Ocean 2015 now accepts XYZ images as input (textures, envmaps, …) and handles it with the same accuracy as XYZ colors. Image pixels are converted to physically plausible spectra on the fly, without any gamut limitation.

Ocean 2015 is to date the only renderer with this ability.

The supported XYZ image formats are Radiance HDR (in XYZE encoding) and OpenEXR.

CIE XYZ color chart

The colorimetry toolbox now displays the sampled values on a CIE XYZ color diagram, as well as the XYZ input color picker.

The new postprocessing parameter allows choosing AdobrRGB output
The new postprocessing parameter allows choosing AdobrRGB output

Export to Adobe RGB

The post-processing filter which converts XYZ renders to RGB now accepts AdobeRGB as an alternative color space, for better accuracy with vivid colors.

Other Ocean 2015 features

New features will be presented this fall in a weekly “feature higlight” update. In the meantime, you may discover them by downloading Ocean 2015