- TM-30-15 is a new and improved IES method for characterizing the color rendering ability of white light sources.
- While CRI and extended CRI utilize 8 and 15 color samples, respectively, they do not necessarily represent the actual colors that we would encounter in the real world.
- The new fidelity index(Rf) developed under TM-30-15, on the other hand, utilizes 99 color samples in its caluclation, providing a much more statistically representative and reliable metric in describing a light source’s ability to faithfully render colors.
- In line with CRI,the best possible score for Rf under the TM-30-15 is 100.
WHAT ARE DIFFERENCES BETWEEN TM-30-15 and CRI?
- First, CRI provides information only about fidelity, i.e. the accurate rendition of color such that objects appear similar to how they would under familiar reference illuminants such as daylight and incandescent light. However, CRI doesn’t provide any information on saturation.
- The picture below shows two images with the same CRI and different levels of saturation. While the images obviously look very different because of different saturation levels, CRI doesn’t provide a mechanism of describing these differences.
- TM-30-15 uses also the Gamut Index (Rg) to describe differences in saturation.
- Second, whereas CRI uses only 8 color samples to determine fidelity, the TM-30-15 uses 99 color samples. A lighting manufacturer could ‘manipulate’ the CRI system by ensuring that certain peaks of the light source spectra matched one or a few of the eight color samples used in calculating CRI and thus achieve an artificially high CRI value. Such an artificially high CRI value would result in a lower TM-30-15 value since TM-30-15 has 99 color samples. After all, matching spectrum peaks to 99 color samples is very difficult!
- As already mentioned there are two main indexes when useing TM 30-15 measurment: TM-30 Rf and TM-30 Rg.
- Rf is the TM-30 measure for average color fidelity. It is analogous to the CIE CRI, but uses significantly more modern color science, which makes it more accurate.
- Rg is the TM-30 measure for average relative gamut. In illumination engineering (as opposed to displays), gamut is the area enclosed by the chromaticity of a set of color samples. When TM-30 Rf is above 60, TM-30 Rg is between approximately 60 and 140. Typically, gamut measures are thought of as average measures of chroma level (saturation), although both hue and chroma shifts contribute to changes in gamut. Values greater than 100 indicate an average increase in gamut, whereas values less than 100 indicate an average decrease in gamut.
LED strips FULL SPECTRUM TM 30-15