![\"CRI](\"https:\/\/www.ihylight.com\/wp-content\/uploads\/2026\/09\/CRI-vs-TM-30-for-COB-LED-Lighting-How-to-Specify-Rf-Rg-R9-and-Color-Quality-1024x576.webp\")
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Two COB LEDs can both be labeled CRI 90 or CRI 95 and still render skin tones, fabrics, coatings, food, packaging, or photographed objects differently. For an OEM buyer, that is the practical reason to compare CRI vs TM-30<\/strong>\u00a0rather than treating a high CRI number as a complete color\u00a0quality specification.<\/p>\n CRI remains useful, but projects that depend on accurate or intentional color appearance may need R9, TM-30 Rf and Rg, spectral information, and representative sample approval. The goal is not to replace every CRI requirement with a longer list of metrics. It is to specify enough information for the application and make supplier data genuinely comparable.<\/p>\n CRI, usually reported as Ra, summarizes the average color shift of eight standardized samples. The Illuminating Engineering Society defines Ra as the average shift of eight intermediate\u00a0saturation colors. That makes CRI convenient for initial screening, but an average can hide differences in individual colors.<\/p>\n ANSI\/IES TM-30-24 takes a broader approach. It evaluates overall color fidelity, gamut area, and hue-specific behavior using numerical and graphical information. The method is intended for lighting specifiers, manufacturers, engineers, and designers, which makes it particularly relevant when a COB LED must be specified rather than simply described as \u201chigh CRI.\u201d<\/p>\n CRI is still useful when comparing products against a familiar minimum requirement, screening suppliers, or working with a specification that explicitly calls for Ra. A CRI 90 or CRI 95 requirement can quickly eliminate sources that do not meet the project’s basic fidelity target.<\/p>\n The problem begins when buyers assume that two LEDs with the same Ra will produce the same visual result. DOE technical material shows that light sources with the same CRI can render individual colors differently because an average score hides those differences.<\/p>\n For general illumination, CRI may be sufficient for an early selection stage. For product display, photography, color matching, premium retail, inspection, or supplier substitution, additional color data becomes more useful. When the appearance of specific reds, skin tones, finishes, or branded colors matters, the next step should be to request R9, TM-30 information, spectral data, or a physical sample under representative conditions.<\/p>\n TM-30 should not be treated as a single \u201cbetter CRI\u201d number. Its value comes from combining several pieces of information.<\/p>\n Rf describes average fidelity to a reference. Rg describes average gamut area, indicating whether colors are, on average, more or less saturated than under the reference. The Color Vector Graphic then shows how hue and chroma change across different color regions. IES TM-30-24 also includes local fidelity, local chroma shift, and local hue shift measures.<\/p>\n Rf uses a 0\u2013100 scale, with a higher value indicating closer average fidelity to the reference. However, the highest possible fidelity is not automatically the right design choice for every application. A project may value faithful rendering, deliberate saturation, or a balance between the two.<\/p>\n Rg needs even more care. A value above 100 indicates an average increase in gamut or saturation relative to the reference, while a value below 100 indicates an average reduction. It is therefore incorrect to treat a higher Rg as a universal quality ranking. DOE guidance emphasizes that Rf and Rg are average values and cannot, by themselves, show exactly which colors have shifted.<\/p>\n For purchasing, the better question is not \u201cWhat is the highest Rg available?\u201d but \u201cWhat color-rendering behavior is required by the application?\u201d A neutral color-matching task and a retail display designed to emphasize certain merchandise may call for different spectral choices.<\/p>\n Two COB LEDs can have similar Rf and Rg values while treating particular hue regions differently. That is where the TM-30 Color Vector Graphic becomes useful.<\/p>\n The graphic provides a visual representation of hue and chroma shifts around the hue circle. For applications where certain colors are critical, the graphic can reveal information that disappears inside average values.<\/p>\n This matters when evaluating skin tones, fabric, food, paint, product finishes, artwork, or camera\u00a0facing objects. A supplier report showing only Rf and Rg may be adequate for preliminary screening, but a color\u00a0critical OEM project may benefit from the complete report or supporting spectral data.<\/p>\n A common replacement problem occurs when the original and replacement COB have the same nominal CCT and CRI, yet the illuminated object looks different after installation.<\/p>\n The reason is that neither CCT nor Ra uniquely defines the spectral power distribution. Different spectra can produce similar headline metrics while distributing energy differently across visible wavelengths.<\/p>\n <\/p>\n R9 is a useful supplemental metric because it describes saturated red rendering and is not included in the calculation of Ra. DOE notes that R9 can be particularly relevant to red objects and skin tones.<\/p>\n CCT also needs to be interpreted correctly. Two COB LEDs labeled with the same nominal CCT do not necessarily have identical spectra or identical color rendering. Duv, spectral power distribution, R9, and TM-30 results can reveal differences that a single CCT\/CRI pair cannot.<\/p>\n For replacement or supplier substitution, compare the original and proposed COB under equivalent conditions. \u201cSame wattage + same CCT + same CRI\u201d is not enough when a visual match matters. If the application is stage or camera\u00a0facing lighting, the existing guide to color quality requirements for stage lighting COB LEDs<\/u><\/strong><\/a>\u00a0provides a broader application context that includes CRI, R9, TM-30, Duv, spectrum, and other system considerations.<\/p>\n Not every COB LED project needs a full TM-30 requirement. Adding metrics without a clear application reason can make sourcing more complicated without improving the final product.<\/p>\n A practical approach is to increase the depth of color evaluation as the cost of color mismatch increases.<\/p>\nCRI vs TM-30: What Is the Difference for COB LED Selection?<\/b><\/strong><\/h2>\n
When CRI Is Useful\u2014and When a CRI Number Is Not Enough<\/b><\/strong><\/h3>\n
How to Read TM-30 Rf, Rg, and the Color Vector Graphic<\/b><\/strong><\/h2>\n
How to Interpret Rf and Rg Without Treating Them as \u201cHigher Is Better\u201d<\/b><\/strong><\/h3>\n
When the Color Vector Graphic Matters More Than the Average Scores<\/b><\/strong><\/h3>\n
Why Two High<\/b><\/strong>\u00a0<\/b><\/strong>CRI COB LEDs Can Still Render Colors Differently<\/b><\/strong><\/h2>\n
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<\/p>\nSpectrum, R9, and CCT: What a Buyer Should Compare Beyond Ra<\/b><\/strong><\/h3>\n
When Should an OEM Specify TM-30 Instead of CRI Alone?<\/b><\/strong><\/h2>\n