ASTM E1079-21 PDF

Full title and description

St ASTM E1079-21 — Standard Practice for Calibration of Transmission Densitometers. Provides recommended procedures, reference apparatus, and traceability requirements for calibrating transmission densitometers used to measure diffuse optical density on radiographic films.

Abstract

ASTM E1079-21 specifies a concise, practice-level method for calibration and periodic verification of transmission densitometers that measure optical (transmittance) density on radiographic film. The practice identifies required reference materials (step tablets traceable to NIST or equivalent), acceptable measurement ranges, and links to related ISO and ASTM documents used as background or normative references. It is intended to ensure consistent, traceable optical density measurements in radiographic quality control and nondestructive testing workflows.

General information

• Status: Active
• Publication date: November 1, 2021
• Publisher: ASTM International
• ICS / categories: 17.180.30 (Optical measuring instruments)
• Edition / version: E1079-21
• Number of pages: 2

Scope

This practice covers the calibration of transmission densitometers used to perform measurements of diffuse optical density on radiographic films. It defines the minimum reference equipment and traceability requirements (for example, NIST-traceable step tablets), the density range to be covered, and the purpose and use of calibration to assure accurate optical density values for production and inspection radiographs. It does not address all safety considerations for use.

Key topics and requirements

• Use of calibrated step tablet(s) that cover the optical density range used in production radiographs, with traceability to NIST or equivalent.
• Procedures for establishing densitometer response across relevant density steps and for verifying instrument linearity and repeatability.
• Reference to applicable ISO standards for geometry and spectral conditions in optical density measurement (for example ISO 5 series and ISO 14807) as background.
• Documentation and calibration certificate requirements for reference artifacts (tablet ID, recorded step densities, traceability statement).
• Guidance on periodic verification and when recalibration is required to maintain measurement confidence in nondestructive testing applications.

Typical use and users

Used by calibration laboratories, nondestructive testing (NDT) facilities, radiography service providers, quality assurance and metrology personnel, and manufacturers or maintenance organizations that perform or rely on optical density measurements of radiographic film. Typical use cases include routine instrument calibration, acceptance testing of densitometers following repair, and establishing traceable measurement systems for radiographic image quality control.

Related standards

Commonly referenced documents include Terminology E1316, ISO 5-1/5-2/5-3 (density measurement geometry and spectral conditions), ISO 14807 (performance of transmission/reflection densitometers), and related ASTM practices and test methods used in radiographic system evaluation and laboratory accreditation (examples: E1254, E1936, E492). For some Code applications, a related ASME practice (SE-1079) is also noted.

Keywords

transmission densitometer, calibration, optical density, radiographic film, traceability, step tablet, NIST, nondestructive testing, densitometry

FAQ

Q: What is this standard?

A: ASTM E1079-21 is a standard practice that defines how to calibrate transmission densitometers used to measure diffuse optical density on radiographic films, including reference artifacts and traceability requirements.

Q: What does it cover?

A: It covers selection and use of calibrated step tablets (traceable to NIST or equivalent), procedures to verify densitometer response across the working density range, documentation of calibration, and references to related ISO/ASTM documents; it does not provide exhaustive safety guidance.

Q: Who typically uses it?

A: Calibration laboratories, NDT and radiography service providers, QA/metrology staff, instrument manufacturers, and any organization needing traceable optical density measurements of radiographic film.

Q: Is it current or superseded?

A: The designation E1079-21 indicates the 2021 edition. As of the publication date shown (November 1, 2021) this edition is current; users should confirm whether a newer revision exists before purchase or application.

Q: Is it part of a series?

A: It is a practice under ASTM Committee E07 (Nondestructive Testing), Subcommittee E07.01 (Radiology). It also cross-references related ASTM and ISO documents relevant to densitometry and radiographic system evaluation.

Q: What are the key keywords?

A: Calibration, transmission densitometer, optical density, radiographic film, NIST traceability, step tablet, densitometry, nondestructive testing.