ASTM D85-05(2023) PDF

Overview

ASTM D85-05(2023) Standard Specification for Ochre Pigment establishes the essential requirements for ferrous earthy pigments known as ochre. Developed by ASTM International, this standard guides the characterization and quality assessment of ochre pigments, particularly for industrial, artistic, and construction applications. Ochre pigments addressed by this standard are hydrated iron oxides blended with a siliceous base, and must be free from both intentional impurities and added coloring matter.

ASTM D85-05(2023) supports reliable pigment sourcing and product consistency by specifying testing methodologies, minimum composition, maximum impurities, and uniformity requirements-ensuring ochre pigment quality for manufacturers, suppliers, and end-users.

Key Topics

• Material Composition: The ochre pigment must be a hydrated oxide of iron on a siliceous base, with no added impurities or other coloring agents. Key compositional parameters include:

  • Minimum ferric oxide content: 17%
  • Maximum calcium oxide content: 5%
  • No added lead chromate or organic coloring matter

• Quality Attributes:

  • Moisture and other volatile matter: Not more than 1%
  • Coarse particles (residue on 45 μm sieve): Not more than 1%

• Performance Tests: The standard references systematic test methods for determining pigment quality, including:

  • Chemical analysis of dry pigment (ASTM D50)
  • Testing for coarse particles (ASTM D185)
  • Assessment of mass color and tinting strength (ASTM D387)
  • Determination of volatile matter (ASTM D1208)
  • Moisture content evaluation (ASTM D280, Method A)

• Sampling Procedures: Specifies representative sampling requirements to ensure batch consistency-including the number of samples relative to production volumes.

• International Alignment: Complies with the World Trade Organization Technical Barriers to Trade (WTO TBT) principles for globally recognized standardization.

Applications

Ochre pigments conforming to ASTM D85-05(2023) play a vital role in multiple sectors, including:

• Paints and Coatings: Used as a natural pigment for producing a range of yellow, orange, and brown hues in architectural, industrial, and artistic paints.
• Construction Materials: Contributes earth tones to building materials such as plasters, mortars, bricks, and ceramics.
• Artistic Products: Valued by artists and manufacturers of art materials for its unique color properties and stability.
• Restoration and Conservation: Utilized in historical restoration projects to match original ochre finishes due to its natural composition and heritage significance.

The rigorous specifications of ASTM D85-05(2023) ensure pigments exhibit reliable color consistency, durability, and safety by minimizing unwanted impurities and guaranteeing predictable performance across uses.

Related Standards

ASTM D85-05(2023) refers to several key ASTM methods to support comprehensive ochre pigment evaluation:

• ASTM D50 - Chemical Analysis of Yellow, Orange, Red, and Brown Pigments Containing Iron and Manganese
• ASTM D185 - Methods for Coarse Particles in Pigments
• ASTM D387 - Method for Color and Strength of Chromatic Pigments with a Mechanical Muller
• ASTM D280 - Methods for Hygroscopic Moisture (and Other Matter Volatile Under the Test Conditions) in Pigments
• ASTM D1208 - Methods for Common Properties of Certain Pigments

Adopting ASTM D85-05(2023) and its referenced methods helps manufacturers, laboratories, and users maintain quality control, meet regulatory requirements, and foster trust in the supply chain for ochre pigments and related products.

Keywords: ochre pigment standard, ASTM D85, hydrated iron oxide, pigment testing, ochre quality specification, industrial pigments, ochre applications, international pigment standard.