New Procedure Standard for Electron Microscopy Published

New Procedure Standard for Electron Microscopy Published – June 2026

The field of image technology achieved an important milestone in June 2026 with the publication of a new international standard addressing the measurement and assurance of resolution in high-resolution transmission electron microscopes (HREM). The newly released ISO 25387:2026 details robust, scientifically grounded procedures for determining the point (Scherzer) resolution of analytical electron microscopes. This single, highly specialized standard offers essential guidance for professionals engaged in materials science, electron microscopy, and advanced research, emphasizing accuracy, reproducibility, and compliance with global practices.

Overview / Introduction

The quality and reliability of high-resolution imaging are essential in materials science, life sciences, and nanotechnology. Transmission electron microscopes (TEM) are critical instruments in these sectors, enabling researchers to visualize structures at sub-nanometre resolution. However, ensuring that different organizations, laboratories, and instruments achieve consistent, validated measurements has remained a challenge—until now.

Standards like the newly published ISO 25387:2026 serve as fundamental references for laboratories, research centers, and industrial facilities seeking to:

Demonstrate measurement credibility
Achieve compliance with regulatory and customer demands
Maintain global competitiveness in R&D

In this article, professionals will find a thorough summary of the new standard’s scope, key requirements, impacts on the image technology sector, and actionable steps toward compliance.

Detailed Standards Coverage

ISO 25387:2026 – Procedures for Determining the Point Resolution of High-Resolution Transmission Electron Microscope

Microbeam Analysis — Analytical Electron Microscopy — Procedures for Determining the Point Resolution of High-Resolution Transmission Electron Microscope

Published by ISO on June 9, 2026

This pivotal standard sets out a uniform method for determining the point resolution, specifically the Scherzer resolution, in high-resolution transmission electron microscopes (HREM). The framework extends to specifying procedures for evaluating the real spherical aberration coefficient of the objective lens—the key determinant of achievable imaging resolution. By providing a step-by-step protocol anchored in information theory, the standard enhances consistency across institutions and instrumentation.

Scope and Applicability:

Specifies methods for measuring the point resolution (Scherzer resolution) of HREMs capable of sub-nanometre imaging
Details procedures for experimental measurement using fast Fourier transform (FFT) analysis of HREM images and identification of critical parameters such as the real spherical aberration coefficient
Applies to HRTEMs with cold field emission gun (CFEG), Schottky emission gun (SEG), thermal field emission gun (TFEG), or thermionic emission gun (TEG), provided three or more dark rings are observable in the FFT pattern
Excludes information limits, lattice resolution, STEM resolution, and is not applicable to Cs-corrected TEMs

Key Requirements and Specifications:

Clearly defined measurement protocol for Scherzer resolution, referencing the phase contrast transfer function (PCTF), spherical aberration, and Scherzer focus
Procedures for sample preparation, with emphasis on using amorphous thin films (≤10 nm) and internal calibration using colloidal gold nanoparticles
Analytical steps include:
1. Calculation of provisional Scherzer focus based on manufacturer’s spherical aberration coefficient
2. Set up of the TEM for optimal imaging conditions
3. Recording a through-focus image series
4. FFT analysis and extraction of diffractograms
5. Measurement of the diameters of three dark rings in FFT patterns
6. Calibration of spatial frequency using gold lattice reflections
7. Calculation of defocus and spherical aberration coefficient from experimental data
8. Determination of experimental point resolution following documented mathematical formulas
Reporting of uncertainty in all measurements

Who Needs to Comply:

Scientific research laboratories utilizing HREM for materials characterization
Industrial labs in electronics, metallurgy, and nanotechnology
Quality assurance and compliance officers tasked with ensuring measurement traceability
Procurement teams sourcing electron microscopy equipment and services

Practical Implications for Implementation:

Harmonizes laboratory protocols across different sectors, improving result comparability
Facilitates training and onboarding through a single reference procedure
Enhances instrument performance evaluation, aiding maintenance and procurement decisions
Allows for accreditation and external auditing based on standardized procedures

Key highlights:

Set universal criteria for determining point (Scherzer) resolution of HREM
Includes methods for real spherical aberration coefficient measurement
Ensures consistent instrumentation evaluation across research and industry

Access the full standard:View ISO 25387:2026 on iTeh Standards

Industry Impact & Compliance

How This Standard Affects Businesses and Laboratories

With the release of ISO 25387:2026, laboratories and industries working with transmission electron microscopes are now equipped with a definitive protocol for assessing point resolution—a metric tied to image quality, reliability, and scientific credibility. Consistent adoption will enable:

Direct comparison of measurement results between organizations on a national and international scale
Objective benchmarking of equipment and operator performance
More reliable compliance with contractual requirements and regulatory standards

Compliance Considerations

Organizations should prioritize:

Gap Analysis: Evaluate current resolution assessment practices against the new ISO procedures.
Training: Ensure laboratory staff and equipment operators understand and implement the procedural requirements, including sample preparation and analytical steps.
Documentation: Update standard operating procedures (SOPs) and quality management documentation to reflect the ISO 25387:2026 protocols.
Supplier Engagement: Communicate with microscope manufacturers and calibration service providers regarding expected data, documentation standards, and compliance timelines.

Benefits of Adoption

Enhanced confidence in analytical results, supporting R&D investment and publication
Reduced risk of out-of-specification results leading to costly rework or non-compliance
Strengthened market reputation and increased opportunities for laboratory accreditation

Risks of Non-Compliance

Inconsistent data sets, leading to poor comparability or invalid conclusions
Audit findings that jeopardize laboratory accreditation or customer relationships
Increased resource requirements for corrective actions during regulatory review

Technical Insights

Common Technical Requirements

Several technical aspects in ISO 25387:2026 should be consistently observed:

Use of weak phase objects (ultrathin amorphous films) for accurate point resolution assessment
Precise calibration of the spatial frequency axis, typically via embedded gold nanoparticle lattice spacings
Implementation of FFT image analysis, focusing on the appearance and measuring of at least three dark rings in the diffractogram
Correction for envelope functions (both temporal and spatial coherency), ensuring that dampening effects do not interfere with identification of dark ring positions

Best Practices for Implementation

Develop thorough documentation and image capture templates, ensuring that each experimental step aligns with the standard
Invest in training for staff on both sample preparation and advanced image analysis
Regularly verify and calibrate instrument parameters, documenting all steps for audit trails
Use reference materials and control samples to validate the measurement chain

Testing and Certification Considerations

Establish traceability for spatial frequency calibration via certified reference materials (e.g., colloidal gold nanoparticles)
Maintain comprehensive records for each assessment, including raw images, FFT analyses, calibration data, and uncertainty calculations
Prepare laboratories for third-party assessments or ISO/IEC 17025 accreditation leveraging the ISO 25387:2026 framework

Conclusion / Next Steps

The introduction of ISO 25387:2026 represents a significant stride forward in harmonizing and advancing measurement protocols in image technology. By providing a clear, repeatable, and validated procedure for assessing point resolution in HREM, the standard empowers both experienced professionals and emerging researchers to achieve the highest levels of data integrity and instrument performance.

Key takeaways:

The standard delivers global consensus on point resolution measurement for HREM
It prioritizes accuracy, comparability, and laboratory traceability
Early adoption leads to immediate improvements in quality assurance and scientific credibility

Recommendations:

Review your laboratory’s current electron microscopy resolution procedures
Initiate training and SOP updates for compliance with ISO 25387:2026
Engage with suppliers and accreditation bodies to ensure seamless implementation
Explore the full text for additional technical guidance and example workflows

Staying current with evolving standards in image technology is key to maintaining a leading edge. Organizations are encouraged to access the full standard and leverage iTeh Standards as their authoritative resource for up-to-date specifications and guidance.