Radiographic testing for film
(RT)
Volumetric defects — pores, inclusions and welding flaws — are hidden inside the material and can cause serious failure only after commissioning.
Radiographic testing (RT) is a well-established and widely accepted method for detecting internal flaws — producing a permanent physical film archive that is directly accepted for many project requirements and standards. Our reporting system delivers an audit-ready report in even less than 24 hours.
- SFS-EN ISO 9712 certification
- Fixed filming bunkers in Naantali and Porvoo, and a mobile filming container for the field
METHOD
PRINCIPLE
During radiographic inspection, the object to be inspected is placed between the radiation source and the X-ray film. X-rays or gamma rays penetrate the material and are attenuated in different ways depending on the material thickness, density and internal discontinuities. The resulting density contrast difference on the film reveals the internal structure of the object.
The developed film is interpreted on a light box by a certified inspector in accordance with the applicable standard and acceptance criteria. The film serves as a permanent document that can be reviewed later if necessary. The method is standardised in ISO 17636-1 and accepted in practically all industrial project requirements.
Note
RT is suitable for all metallic materials regardless of their magnetic properties. The method is particularly strong in situations where project requirements specifically demand film radiography or long-term physical archiving.
SUITABILITY
SUITABLE MATERIALS AND STRUCTURES
- Carbon steel and alloy steels
- Stainless steel (austenitic and ferritic)
- Aluminium and non-ferromagnetic alloys
- Castings and forgings
- Pipes, pressure equipment and tanks
- Welded joints with different geometries
AUDIT PROCESS STEP BY STEP
Before radiography, the weld or area to be inspected is visually examined. Surface defects, spatter, or incorrect geometry are documented and, if necessary, rectified before radiography begins.
The radiation source, source-to-object distance, direction of examination, film type, intensifying screens and image quality indicators (IQI) are selected. The parameters are optimised according to the material thickness and geometry in accordance with the ISO 17636-1 requirements.
The film is placed in a cassette behind the area to be examined. The exposure is carried out under controlled conditions in a radiation-shielded area or a bunker. X-rays or gamma rays pass through the object and expose the film.
The film is developed in a chemically controlled process. The density, contrast, sharpness of the film, and any processing faults are inspected. The image quality indicators ensure that the standard requirements are met.
A certified Level II or Level III inspector interprets the film using a film viewer. The inspection report includes a description of the inspected item, parameters used, film archive, detected indications, and the acceptance decision — ready to be attached to the QA/QC documentation.
TYPICAL APPLICATIONS
01
Welds in piping and prefabricated piping — preparation prior to installation
02
Pressure equipment welding and tank structures (PED 2014/68/EU) — film archive in accordance with project requirements
03
Welded joints in shipyards and shipbuilding structures — documentation complying with regulatory requirements
04
Vcritical welds in power plants and the process industry — long-term film archive
05
Detection of internal defects — pores, inclusions, and cracks — in castings
06
Sites where the customer or standard specifically requires film radiography as a permanent physical form of documentation
RT MUIDEN NDT METHODS ALONGSIDE
The following comparison helps to select the most suitable method or combination of methods for the situation:
| Feature | RT (film) | dRT | UT / PAUT | MT / PT |
|---|---|---|---|---|
| Internal volumetric defects | ✓ Excellent | ✓ Excellent | ✓ Excellent | ✗ Not suitable |
| Pintaviat | Limited | Limited | Limited | ✓ Excellent |
| Non-ferromagnetic materials | ✓ Suitable | ✓ Suitable | ✓ Suitable | not suitable |
| Visual document | ✓ Film (physical) | ✓ Digital image | ✗ No image | ✗ No image |
| Permanent physical archive | ✓ Yes — film | Digital | ✗ No | ✗ No |
| Acceptability in requirements | ✓ Very extensive | Growing | ✓ Extensive | ✓ Extensive |
| Radiation-controlled area | Required | Required | ✓ Not needed | ✓ Not needed |
| Reporting speed | Development time + interpretation | ✓ Fastest | ✓ Fast | ✓ Fast |
X-ray — Radiograph (film)
DR — Digital radiography
UT / PAUT — Ultrasonic Testing
MT / PT — Magnetic Particle / Penetrant Testing
Note
The choice between RT and dRT often depends on project requirements. Film radiography is still a requirement in many older standards and client guidelines — particularly for applications requiring a long-term physical archive. In newer projects, digital RT (dRT) is often the faster and more cost-effective choice.
Customer benefits
Broad acceptability of project requirements
Film radiography is an established, internationally recognised method. The project requirements of many pressure equipment standards, client guidelines and regulatory authorities specifically mention ISO 17636-1 film radiography.
Permanent physical documentation
Film is a physical archive document — it does not disappear in system changes. It is particularly suitable for applications where a long-term archiving obligation is part of the project requirements.
Speed and flexibility
Our reporting system delivers an audit-ready inspection report in under 24 hours. When needed, inspections can be carried out at nights or on weekends — with as little as 24 hours' notice on-site.
Safety and compliance
Detect critical internal flaws before structures are put into service. Reporting complies with ISO 17636-1, SFS-EN ISO 9712 and project-specific requirements.
Fixed bunkers + field capacity
Three radiographic bunkers in Naantali, two in Porvoo. A mobile radiographic container enables on-site radiography at the customer's premises — including the inspection of pre-fabricated parts at the installation site.
Reinterpretation without reshooting
Developed film can be reviewed again later — by multiple inspectors. Suitable for applications where film radiography specifically is required.
QUALIFICATION
STANDARDS AND CERTIFICATION
NDT Aura Oy's inspectors operate in accordance with the standards listed below — a technically competent and legally acceptable inspection result.
NDT programme
WE RUN A COMPREHENSIVE NDT PROGRAMME
An individual inspection method covers only a specific set of defect types. Comprehensive quality assurance often requires a combination of methods:
NDT Aura Oy can consult on the formation of the most suitable inspection programme for the object
based on the risk assessment and applicable standards.
FREQUENTLY ASKED QUESTIONS ABOUT FILM X-RAY INSPECTION (FAQ)
In both methods, X-ray or gamma radiation penetrates the component and reveals internal defects. The difference lies in how the image is captured: with film radiography, the image is produced on industrial X-ray film, which is chemically developed, whereas in digital RT, the image is captured on a digital detector and is available immediately. Film radiography produces a physical archive that is widely accepted in legacy project requirements and client specifications. Digital RT is a faster and more cost-effective alternative when project requirements permit.
Film radiography is a recommended choice when: (1) client instructions or project standards specifically require ISO 17636-1 film radiography, (2) a long-term physical archive is required without dependence on digital systems, or (3) it is a regulatory inspection where the acceptability of the film is more straightforward just to be sure.
Our reporting system enables a completed inspection report to be delivered in even less than 24 hours from the inspection being carried out. The film development process is taken into account in the schedule — in urgent situations, we can jointly assess the schedule for even a larger scope and act accordingly.
X-ray inspection requires a radiation-controlled area during imaging — personnel in the vicinity must be moved to a safe distance. Inspections are often carried out at night or at other quiet production times to minimise disruption to production.
Yes. Unlike magnetic particle testing (MT), film radiography is suitable for all metals regardless of their magnetic properties — including aluminium, austenitic stainless steel, and other non-ferromagnetic materials.
NDT aura will provide the client with an order form describing the object: material, wall thickness, welding method, volume of welds or surface area to be inspected, applicable standard or project requirement, and the desired schedule. Drawings and isometric views will significantly speed up the preparation of the quotation.
Request for quotation
Request a quote for radiographic film inspection
(RT) — Inspection report in under 24 hours, flexible execution, permanent film archive
Tell us about the inspection object, material, applicable standard and schedule — we will respond to your request for quote quickly. Send the drawings or a short project description, and we will help you choose the technically correct NDT method or combination of methods.