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JIS L 1055 vs. AATCC TM203: Light Blocking Test Methods for Blackout Fabrics
In the global textile export trade, compliance testing for blackout curtains is a frequent source of order disputes. The most typical technical conflict arises between the Japanese JIS L 1055 and the American AATCC TM203 standards. Many manufacturers fail to understand the fundamental difference in how these two standards define “Light Blocking,” leading to scenarios where products rated as “Grade 1 Blackout (99.99%)” in Japan are rejected in the US market for being “translucent.”
This article provides an authoritative comparative analysis and manufacturing solutions across three dimensions: technical principles, testing methods, and judgment criteria.
Core Difference: Human Perception (JIS) vs. Instrument Data (AATCC)
The greatest difference between JIS L 1055 and AATCC TM203 lies in the dimension of their judgment criteria.
Simply put, Japan’s JIS L 1055 standard focuses on “Human Sensory Experience (Illuminance),” measuring the level of brightness perceived by the human eye under strong light conditions. Conversely, the American AATCC TM203 standard focuses on “Absolute Physical Data (Spectral Transmission),” using precision instruments to detect the absolute penetration of light rays. This discrepancy explains why “99.99%” is considered top-tier blackout in Japan, yet often fails to meet the “Blackout” requirement in US commercial standards.
Deep Dive: JIS L 1055 (Japanese Standard)
Test Method: Illuminance Method (Method A)
JIS L 1055 (Testing methods for light blocking effect of curtain materials) is the core standard for the Japanese curtain industry, typically employing Method A (Illuminance Method).
- Simulation Scenario: Simulates the visual experience of a person inside a room when the curtain is subjected to strong summer noon sunlight.
- Light Source Intensity: Uses an artificial light source of 100,000 Lux to directly irradiate the fabric sample (simulating direct sunlight).
- Detection Method: An Illuminance Meter is placed behind the fabric to measure the illuminance (Lux) of the transmitted light.
NIF Light Blocking Grade System (Fact-Checked)
The Nippon Interior Fabrics Association (NIF) categorizes light blocking performance into three grades based on JIS L 1055 data. Note: The Japanese standard acknowledges “Relative Light Blocking,” meaning minute light leakage is permissible.
| NIF Grade | Rate Requirement | Visual Experience (NIF Definition) | Recommended Application |
|---|---|---|---|
| Grade 1 | ≥ 99.99% | Almost Full Black. Although faces are unrecognizable, extremely faint light perception may exist (0.01% leakage). | Bedrooms, Home Theaters |
| Grade 2 | 99.80% – 99.99% | Dark. Facial outlines can be vaguely recognized. | Standard Bedrooms |
| Grade 3 | 99.40% – 99.80% | Dim. Facial expressions are visible, but the light is insufficient for office work. | Living Rooms, Studies |
⚠️ Industry Insight: Why is NIF Grade 1 (99.99%) still controversial?
Many buyers mistakenly believe “Grade 1” means “Total Blackness,” but this is a mathematical misconception. The NIF Grade 1 standard allows for <0.01% light leakage.
Under the intense 100,000 Lux test of JIS L 1055, a 0.01% transmission means approximately 10 Lux of light enters the room.
What is 10 Lux? It is equivalent to the brightness of 10 candles or twilight. Therefore, Japan’s “Grade 1” is NOT equal to the American “Blackout.” Addressing this point, since 2018, NIF has encouraged companies to label 100% products separately (e.g., “Complete Blackout”) to distinguish them from standard 99.99% products.
Deep Dive: AATCC TM203 (American Standard)
Test Method: Spectrophotometric Method
AATCC TM203 (Light Blocking Effect of Textiles: Spectrophotometric Method) is the gold standard for the US market, particularly within the Hospitality Industry.
- Detection Principle: This standard does not rely on subjective human perception but uses a high-precision Spectrophotometer.
- Spectral Analysis: The instrument analyzes the spectral transmittance of light through the fabric. It captures not just visible light, but even minute photon penetration.
- Zero Tolerance: The sensor is far more sensitive than the human eye or a standard Lux meter.
The US “Zero Tolerance” Policy: Blackout vs. Dimout
In US commercial procurement standards, the definition of “Blackout” is absolute. The result from AATCC TM203 determines the product’s classification:
- 100% Blackout: Instrument reading must be 0.00%. No light transmission is permitted.
- Dimout (Physical Shading): Instrument reading > 0.00% (e.g., 0.01% – 5%). Such fabrics can only be labeled as “Dimout.” They function by physically reducing light rather than blocking it completely.
Critical Warning: Many fabrics that test at 99.99% (Grade 1) in Japan often show 0.01% – 0.05% transmission under US AATCC instruments. Under the US system, these are Dimouts. Labeling them as “Blackout” for export risks immediate rejection.
Technical Comparison Table (JIS vs. AATCC)
To visualize the differences, here is a detailed comparison of core parameters:
| Comparison Dimension | JIS L 1055 (Japan) | AATCC TM203 (USA) |
|---|---|---|
| Core Instrument | Illuminance Meter (Lux Meter) | Spectrophotometer |
| Primary Focus | Human Perception (Lux) | Instrument Data (Opacity %) |
| Highest Standard | NIF Grade 1 (≥99.99%) | 100% Blackout (0.00%) |
| Tolerance | Tolerance Exists (Allows 0.01% leakage) | Zero Tolerance (Must be 0.00%) |
| Mainstream Fabric | High-Density Woven Dimout | Coated (4-Pass) or Flocked |
Manufacturing Solutions: Handling Dual Standards
As an export manufacturer, a “one-size-fits-all” product strategy is risky. We recommend differentiated textile solutions based on the target testing standard (featuring BEGOODTEX R&D examples):
1. For the Japanese Market (JIS L 1055): Physical Shading
Recommended Tech: High-Density Dimout
Since the Japanese market prioritizes “hand-feel” and “drape” and permits 0.01% leakage:
- Process Route: Use a “triple-weave” structure with significantly increased density of black yarn in the middle layer.
- Expected Result: Light blocking rate controlled between 99.95% – 99.99%.
- Advantage: Perfectly meets NIF Grade 1 or 2 standards while maintaining fabric softness. No chemical coating odors, compliant with Japanese home washing habits.
2. For the US Hospitality Market (AATCC TM203): Chemical Shading
Recommended Tech: 4-Pass Silicon/Acrylic Coating
Woven fabrics cannot pass the AATCC 0.00% test due to microscopic gaps between yarns. Chemical covering is mandatory:
- Process Route: Must use a “2 layers White + 2 layers Black” (4-Pass) coating process, or higher-cost Flocking.
- Expected Result: Ensures an AATCC TM203 reading of 0.00%.
- Advantage: Secures a true “100% Blackout” certification, meeting the strict sleep environment requirements of 5-star hotels (Hilton, Marriott, etc.).
Frequently Asked Questions (FAQ)
Q1: Can woven dimout fabric (with black yarn inside) pass the AATCC TM203 Blackout test?
A: Almost impossible. Woven dimout fabrics typically achieve 98% – 99.9% light blocking. Under the precision of AATCC 203 instruments, photons penetrate the microscopic gaps (pinholes) between yarns. Without back coating, woven fabrics are defined as “Dimout” in the US.
Q2: Why does 3-Pass coated fabric sometimes fail to reach 0.00%?
A: The main issue is “Pinholes.” The 3-Pass process (usually 1 black layer + 2 white layers) may leave microscopic air bubbles or uneven spots during foaming/drying. Under intense light detection, these become light leaks. High-end US products typically require 4-Pass or 5-Pass processes to seal light paths completely.
Q3: How bright is the 100,000 Lux light source in the JIS standard?
A: It is equivalent to the brightness of direct noon sunlight in summer. The strictness of the Japanese standard lies in the extreme intensity of the light source, which can shine through thick fabrics. If a fabric achieves 99.99% under this intensity, it provides excellent shading for daily household use (where light is typically below 100,000 Lux).
Q4: Is NIF Grade 1 equivalent to 100% Blackout?
A: No. The NIF Grade 1 range is 99.99% – 100%. A fabric at the 99.99% edge of Grade 1 will show starry points of light if observed closely or lit by a phone flashlight. Only Grade 1 fabrics that are coated and achieve actual 100% are close to the American definition of “Blackout.”