Does AWS D1.1:2025 allow digital radiography as a substitute for film RT?

Yes. AWS D1.1:2025 includes provisions for digital radiographic examination techniques (computed radiography and digital detector arrays) as alternatives to film-based RT, provided the technique meets equivalent image quality requirements and is qualified before production use.

What is the difference between CR and DR in radiographic testing?

Computed radiography (CR) uses reusable phosphor imaging plates that are exposed to radiation, removed from the part, then read by a laser scanner to produce a digital image. Direct digital radiography (DR) uses flat-panel detector arrays that capture the image in real time during exposure. DR eliminates the scanning step, making it faster for high-volume work.

Do we need to revise our WPS if we switch from film RT to digital RT?

No — the WPS covers the welding process, not the inspection method. The NDE procedure (separate from the WPS) must be updated to document the digital technique, equipment qualification, sensitivity requirements, and image storage format. Your welding procedure package stays the same; your NDE procedure changes.

How long must digital RT images be archived for structural welds?

AWS D1.1 requires NDE records to be retained per the contract, applicable code, or owner requirement. Many structural contracts specify a minimum of 5–10 years; some owner specs require the life of the structure. Digital images must be stored in a format that prevents degradation and allows retrieval for re-interpretation if required.

Digital RT for structural welds: CR and DR under AWS D1.1

Computed and direct digital radiography are replacing film RT on structural projects. What AWS D1.1:2025 requires before you switch inspection techniques.

Film radiography has been the dominant technique for volumetric examination of structural welds since the 1940s. The image quality is well understood, the acceptance criteria are calibrated to it, and most CWIs learned their RT interpretation on film. But storage costs, processing chemicals, film availability, and turnaround time are all pushing fabricators toward digital alternatives.

Computed radiography (CR) and direct digital radiography (DR) are both seeing wider adoption on structural steel projects. Before a shop or NDE contractor makes the switch, there are qualification requirements, procedure documentation obligations, and practical trade-offs worth understanding.

Film RT vs. digital RT: the core difference

Traditional film radiography uses silver-halide film as the detector. X-ray or gamma energy exposes the film; chemical processing produces a permanent, analog image. The image is read on a light box by a certified interpreter.

Digital techniques replace the film with a different detector:

Computed Radiography (CR): Uses a flexible, reusable photostimulable phosphor (PSP) plate. The plate is loaded into a film-like cassette, exposed in the same geometry as film, then removed and fed into a laser scanner. The scanner reads the stored energy pattern and generates a digital image file. CR hardware is portable and relatively low capital cost compared to DR.
Direct Digital Radiography (DR): Uses a flat-panel detector array — either a direct-conversion panel or a scintillator-coupled flat panel — that converts radiation to an electronic signal in real time. There is no plate to process; the image appears on a monitor during exposure. DR delivers immediate feedback, which matters for repositioning sources and shot optimization on the floor.

Both produce digital image files. Both require appropriate software for display, contrast enhancement, and measurement tools. And both require qualified image quality indicators (IQIs) to demonstrate that the technique meets sensitivity requirements.

What AWS D1.1:2025 requires for digital techniques

AWS D1.1:2025 permits digital radiographic examination provided the technique meets the same image quality (sensitivity) requirements as the film-based procedure. The key requirements:

IQI sensitivity: The technique must demonstrate the same wire IQI or hole IQI sensitivity that would be required for a film technique at equivalent geometry and source-to-film distance. Digital techniques can achieve equivalent or better sensitivity, but the setup must be qualified to demonstrate it — not assumed.

Written NDE procedure: A written procedure must document the digital technique, including the detector type, source-to-detector distance (SDD), exposure parameters, image processing steps, and archival format. The procedure is qualified before production use.

Equipment qualification: The detector, scanner (for CR), and display system must be qualified. This includes establishing the baseline image quality performance of the system and checking it at defined intervals during production.

Display and interpretation requirements: Digital images are interpreted on calibrated monitors, not light boxes. The monitor luminance, resolution, and ambient lighting conditions are part of the technique qualification. An uncalibrated monitor in a bright room does not meet the requirement.

For the specific code language and clause references, consult AWS D1.1:2025 directly and your NDE contractor — provisions can be updated in code cycles, and your project may have supplemental owner requirements that are stricter than the code minimum.

ASTM standards that underpin digital RT

AWS D1.1 references ASTM standards for the conduct of RT examinations. For digital techniques, the key ASTM standards are:

ASTM E2002: Standard Practice for Computed Radiology (CR) for Examination of Weldments
ASTM E2698: Standard Practice for Radiological Examination Using Digital Detector Arrays (DR)
ASTM E747: Wire IQIs — same as for film, the reference for sensitivity demonstration
ASTM E1734: Standard Guide for Radioscopic Examination of Metallic Castings (some provisions referenced for DR real-time work)

Your NDE contractor should be familiar with these standards and should incorporate them by reference in the written procedure.

Practical trade-offs: CR vs. DR vs. film

CR advantages over film: No chemical processing, no darkroom, immediate digital output, reusable plates reduce per-shot material cost. Plates can be formed to fit curved surfaces similarly to film.

CR disadvantages vs. film: Plate handling adds a step; scratched or damaged plates introduce artifacts. Scanning time reduces throughput compared to DR. Plates require calibration and periodic replacement.

DR advantages over CR and film: Real-time image display, fastest throughput, no plates to handle or process. Best for high-volume production environments with repetitive geometry (pipe circumferential seams on a large diameter, for instance).

DR disadvantages: Higher capital cost for the flat-panel detector. Panels are rigid — limited ability to fit curved or complex geometries. Larger physical footprint. More downtime impact if a panel is damaged.

Film advantages that are hard to replicate: Film is a permanent, inherently stable artifact. A film radiograph stored correctly can be re-read fifty years later with the same information. Digital images require active long-term storage management. Film is also flexible enough to handle complex geometries that DR panels cannot.

Where film still wins in structural fab: Complex joint geometries (T-joints, penetrations), field inspection where portability matters more than throughput, and projects with archival requirements that the owner's IT infrastructure cannot reliably support for decades.

NDE procedure documentation for digital RT

Switching to digital RT requires updating your NDE procedure package — specifically the written procedure for radiographic examination. The WPS itself does not change; radiographic examination is an inspection method, not a welding variable.

The updated NDE procedure should document:

Technique type: CR or DR, with specific equipment identification (manufacturer, model, detector size)
Source information: X-ray unit kV range or isotope type (Ir-192, Se-75, Co-60)
Geometry: Source-to-detector distance, source-to-object distance, object-to-detector distance
IQI type and placement: Wire or hole IQI per ASTM E747, placement on source side vs. film side
Image processing: Any gain, contrast, or filtering parameters applied post-exposure
Interpretation conditions: Monitor specifications, ambient lighting, minimum display resolution
Archival format and storage: File format (typically DICONDE for NDT digital images), storage duration, access controls
System qualification frequency: How often the system is re-qualified (typically annually or after major maintenance)

For shops that manage WPS and NDE records in a single audit-ready package, digital RT introduces additional data management: the image files themselves become part of the record, not just a radiographic interpretation report.

Image storage and archival

This is where many shops underestimate the operational change. Film radiographs are physical objects — file them and forget them for five years. Digital images require:

A defined file format that will remain readable (DICONDE is the industry standard for NDT digital imaging)
A storage system with redundancy (at minimum, two separate physical locations)
Periodic media migration to prevent bit rot over multi-year retention periods
Access controls so images cannot be altered after interpretation

If your retention requirement is five years, current magnetic media may be adequate. If your project requires life-of-structure retention (common on bridges, nuclear-adjacent, and some government work), the archival commitment is significant.

Confirm your owner's retention requirement before committing to digital RT. Some owners are not yet equipped to receive and store DICONDE files. Film may still be the contractually required deliverable, even if digital RT would be more efficient for the shop.

Interpreter qualification

The qualification requirements for interpreters of digital RT are the same as for film: ASNT Level II or Level III in Radiographic Testing (RT), with the examination type (RT) specified. Some advanced owner specifications add a digital-technique endorsement or require documented training in digital image interpretation.

For acceptance criteria under AWS D1.1:2025, the digital-vs-film distinction is irrelevant — an interpreter is evaluating the same discontinuity indications against the same dimensional and density criteria. The difference is the display medium, not the standard.

When the switch makes sense

Digital RT is a practical improvement for shops with:

High volume of similar joints (repeated geometry means the technique setup amortizes quickly)
Climate-controlled inspection areas suitable for digital equipment and monitor interpretation
IT infrastructure to handle digital image archival
Owner specifications that accept digital RT or require it

Film remains appropriate for:

Complex or unusual joint geometries
Field work in harsh environments
Projects with archival requirements that digital storage cannot reliably satisfy
Situations where the owner's QA organization is not yet equipped for digital image deliverables

For shops evaluating whether digital NDE is part of a broader quality system upgrade, see our pricing page — the audit-packet export can incorporate NDE reports and interpretation records alongside WPS and welder qualification data.

The bottom line: digital RT is technically equivalent to film when properly qualified, and AWS D1.1:2025 provides the framework to use it. The qualification work up front is real, but so are the operational benefits at scale.

Rule library based on AWS D1.1:2025; verify against your governing edition.