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D211-67 – Standard Test Method Technical Guide
🧪 Standard Coverage and Pigment Classification
ASTM D211-67 (Reapproved 2023) specifies six distinct types of commercially pure lead chromate pigments. These are chemical precipitates consisting of normal or basic lead chromates, and the classification is strictly based on the pigment’s shade, ranging from primrose yellow to dark orange.
| 🟦 Type | 📏 Name | 📐 Classification |
|---|---|---|
| I | Primrose Chrome Yellow | Lightest shade lead chromate pigment (sulfate co-precipitate) |
| II | Lemon Chrome Yellow | Greenish-yellow lead chromate |
| III | Medium Chrome Yellow | Standard yellow orthorhombic lead chromate |
| IV | Light Chrome Orange | Orange shade basic lead chromate |
| V | Dark Chrome Orange | Deep orange basic lead chromate |
| VI | Chrome Yellow for Green | Formulated for blending with blue pigments for chrome greens |
⚙️ Composition and Physical Properties
The pigments must meet the composition requirements prescribed in Table 1 of the standard. Beyond pure composition, the physical properties such as mass color, tint strength, and fineness of dispersion are critical. These are verified using a mechanical muller following ASTM D387 (Test Method for Color and Strength of Chromatic Pigments with a Mechanical Muller) and a Hegman gage per ASTM D1210 (Test Method for Fineness of Dispersion of Pigment-Vehicle Systems). Coarse particles are screened using ASTM D185 (Test Methods for Coarse Particles in Pigments).
💡 Quality Control Insight: The tint strength and mass color of a supplied lot must match a mutual physical standard between the buyer and seller. This ensures visual equivalence in the final paint or coating.
📊 Durability Testing and Performance Limits
For critical exterior applications, the standard mandates accelerated weathering tests per ASTM D822 (Practice for Filtered Open-Flame Carbon-Arc Exposures of Paint and Related Coatings). The test panels must meet strict criteria to ensure adequate performance.
| 🎯 Property Tested | 🥇 Required Specification Limit |
|---|---|
| Specular Gloss Retention | Loss of not more than 30% of original gloss (per ASTM D523) |
| Chalking Resistance | No visible chalking on the exposed panel |
| Color Change Resistance (Lightness) | Color change △L no greater than the limit established for each specific pigment type in Table 2 of the standard |
⚠️ Health and Regulatory Compliance: This standard specifies materials containing lead. It is the sole responsibility of the user to establish appropriate safety, health, and environmental practices and to comply with all applicable regulatory limitations before using these pigments.
❓ Frequently Asked Questions
🔍 What is the primary scope of ASTM D211-67?
The scope defines six types of commercially pure lead chromate pigments: Primrose Yellow, Lemon Yellow, Medium Yellow, Light and Dark Orange, and Chrome Yellow for Green, as detailed in Section 1.1.
💡 How is color strength validated under this standard?
Color strength and mass color are determined using the mechanical muller method, ASTM D387. The results must agree with an established standard acceptable to both the purchasing and selling parties, as per Section 3.2.
⚡ What are the specific gloss retention requirements?
According to Section 3.3, the weathered panel must show a loss of not more than 30% of the original gloss when measured per ASTM D523.
📌 Are the units of measure in imperial or metric?
The values stated in SI units are to be regarded as the standard for this specification. Values