In this case, the profile generator will add the necessary chromaticity adaptation to convert the colors to the selected illuminant.įor further information on illuminants and Abstract Profiles see: Illuminant - Abstract profile. Īlthough the colors are usually encoded using one of the standard D50, D60 or D65 illuminants, you can specify a different illuminant in the drop-down list. The white point, which is identified by its temperature and a symbol (D50, StdA 2856K, Fluorescent F11, etc.) is represented using either XYZ or xyY data calculated as follows: X,Z (Y= 1) = Sum of the matrix product from 350nm to 830nm / Sum of the matrix product from 350nm to 830nm. The illuminant is used to derive the white-point reference for color profiles. You can see other uses of the TRC in Abstract profiles > TRC_-_Tone_Response_Curve. The processing profile is written to disk: When you apply a processing profile manually or using a dynamic profile. That processing profile also stores all the tool tweaks you made in the Editor tab. In the case of a custom TRC, the curve will consist of a linear part and a parabolic part with a seamless connection between the two. As simply viewing the image requires processing, RawTherapee stores the settings it used to show you the image in a sidecar processing profile. You can choose predefined values such as 'standard g 2.2', 'sRGB g=2.4 s=12.92' or build a custom TRC. The TRC is essentially a curve that transforms the initial or input values of the image into values that will be recorded in the output image. Operation of the algorithm Tone Reproduction Curve The 'secret sauce' in this approach is a recipe of three ingredients - (1) use of a relatively neutral camera profile, (2) a flat tone curve to begin with, and (3) use of RT's Colour Toning tool. In the ICC profile generator, you specify the location of the primary colors on the 1931 CIE xy chromaticity diagram using the xy coordinates. The great thing is, since this is based around GIMP and RawTherapee, it's completely free and will work for those with Windows, Mac and Linux systems. The three primary colors - Red, Green, Blue - are additive and form the basis of all other colors. To make the profiles you generate available for use in RawTherapee, save them to the "directory containing color profiles" as specified in Preferences > Color Management. The code and the basic principles are similar to those used for Abstract profiles UsageĪccess this module via the ICC Profile Creator button located either in the bottom-left or top-right of the RawTherapee window. You can generate profiles in accordance with ICC versions 2 and 4, and in both cases you can use custom primaries and modify the illuminant as well as the tone reproduction curve (TRC). the primary colors, the tone reproduction curve, and the white point (illuminant). the A2B or B2A tags, but you can adjust those that are important for a photographer i.e. You cannot adjust all the parameters of an ICC profile with this tool, e.g. RawTherapee can generate output, screen or custom working profiles using the XYZ matrix generated for Custom profiles You can use standard presets as well as custom values. The ICC Profile Creator allows you to generate your own ICC profiles.
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