Film and Television Grade COB Constant Temperature Continuous Photography Light: CRI / TLCI / SSI Color Accuracy Index Interpretation and Light Efficiency Purchasing Guide

1. COB (Chip-on-Board) technology: the disruptive evolution of always-on lights

In the past, film and television LED lights were composed of hundreds of tiny SMD LED beads densely arranged (flat panel lights):

1. Physical defects of traditional array panel lights:

• Each micro-lamp bead is an independent light-emitting point, which will produce terrifying "Multi-Shadow Artifacts" when shining on the subject;
• The light is divergent, and optical accessories such as radome, Fresnel lens (Fresnel) or condenser cannot be installed for precise light shaping;

2. Physical advantages of COB integrated area light source:

• Hundreds of light-emitting chips are directly packaged on the same micro-mirror metal substrate at high density to form a high-density light-emitting "virtual sun point light source" with a diameter of only two to three centimeters;
• Emit pure and unified single point light source, with clean and crisp shadows and sharp edges;
• Equipped with the universal Bowens Mount as standard, various types of deep-polished soft boxes, optical lenses and honeycombs can be added at will to achieve any film-level light effect engraving.

2. Revealing the Color Rendering Index Mystery: Why does CRI 95 still produce a “blue look on corpses”?

Many photographers have purchased high-index affordable constant-light lights with a nominal "CRI > 95", but the skin of the people they photographed has a sickly earthy gray and sallow-green color:

1. Traditional CRI (Ra) deceptive scoring vulnerability:

• CRI (Color Rendering Index) was born in the 1960s. Ra only tested a total of 8 low-saturation neutral pastel color blocks from R1 to R8;
• Cheap LED manufacturers can easily achieve high scores of over 95 on R1-R8 by simply enhancing the yellow-green spectrum;

2. Fatal R9 (saturated pure red) shortcomings:

• The ruddy blood color of human skin and the reflection of capillaries in the dermis are completely determined by the highly saturated red spectrum (R9 color sample);
• In most inferior LED spectra, due to cheap phosphor formulas, there is a serious "energy cliff drop" in the red light band above 660nm, and their R9 score may be only a pitiful 50 or even a negative number!
• Without the irradiation of red light energy, no matter how high the saturation is during post-production color correction, the model’s skin color will always look dull, moldy, and lifeless.

3. Qualified Portrait Light Benchmark: When purchasing, you must check the spectrum test report published by the manufacturer. Not only Ra must be > 96, but the special color rendering index R9 must also be clearly marked > 90!

3. Authoritative film and television-level evaluation benchmarks: TLCI and SSI

1. TLCI-2012 (TV Lighting Conformance Index):

• Developed by the European Broadcasting Union (EBU);
• Simulates the spectral absorption characteristics of modern digital camera CMOS sensors rather than the retina of the human eye;
• Scoring Criteria:
• TLCI 85-100: The color is extremely perfect and does not require any color correction in post-production;
• TLCI < 75: The color is severely distorted and cannot be completely restored in post-film and television color grading.

2. SSI (Spectral Similarity Index):

• A new generation of the most stringent benchmarks developed by the Oscar Science and Technology Committee (AMPAS);
• Completely abandon the comparison of color block samples and directly compare the physical waveform consistency of the lamp spectral curve with the standard physical reference light source (such as 5600K sunlight or 3200K tungsten lamp blackbody radiation curve);
• Lamps with an SSI score higher than 80 (such as Aputure, Nanlite and other professional film and television lamps) mean that their spectrum is continuous and smooth, with no sharp blue light peaks and faults, and can present the purest and most natural true texture of objects.

4. Practical indicators for purchase and heat dissipation and temperature control

1. Effective power (Draw Power) and illumination (Lux):

• Do not be fooled by the "1000W equivalent halogen lamp" promoted by the manufacturer, and look for the real rated power (such as 60W, 100W, 200W, 300W, 600W) on the nameplate of the fuselage;
• For indoor portrait shooting, it is recommended to choose a starting power of 150W to 200W, and use it with a 90cm softbox to provide sufficient exposure margin at ISO 100.

2. Active fan cooling and recording mute control:

• High-power COB dissipates extremely terrible heat and must rely on fans for ventilation;
• In the synchronous recording environment, you must choose a silent mode lamp with a fan noise lower than 20 decibels (dB), or a passive cooling mode that supports the fan to be completely turned off to prevent high-frequency fan whistling from contaminating the lavalier microphone.

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