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Dye Penetrant Inspection (DPI) UV NDT Testing

Dye Penetrant Inspection (DPI) is also referred to as liquid penetrate inspection (LPI) or penetrant testing (PT) is a widely used NDT method.  There are multiple NDT methods to locate surface flaws & defects, but DPI Inspection is by far the fastest for it's inspectors & most cost-effective. 

 Using UV Inspection Lights alongside fluorescent dye inspection makes this method of inspection faster & even more reliable.  Depending on the fluorescent dyes used, and the use of a UV365 Light - your indication will fluoresce brightly to bring attention to even the smallest surface defect, which could otherwise be missed using a non-fluorescent dye.   

 Advanced NDT LTD stock a wide range of Labino Ultraviolet Lights/Lamps & Labino UV LED Blacklight Torches to suit your DPI testing needs & application with the use of fluorescent dyes for wet testing on ferromagnetic materials to detect surface cracks, defects and abnormalities. 

Dye Penetrant Inspection is a non-destructive testing method used to detect surface defects such as cracks, porosity, and other flaws in your material. This process involves applying a dye penetrant to the material, allowing it to soak into any imperfections, and then exposing the material to a UV light to make the dye penetrant visible.  This allows for accurate and reliable surface inspection.


See the Labino MB with 'Athena' spray-can attachment accessory, a real game changer for DPI inspections, a UVG5 UV Head Torch for hands-free inspection for hard-to-reach or difficult inspection areas & the Labino GX Orion for Overhead Bench Inspections, IP68 rated for wash station areas for cleaning after inspection - aswell as the all new Labino Cosmos - a large IP68 rated UV light specifically designed for large wash station areas.

Ultraviolet Inspection Lights / Lamps & UV LED Blacklight Torches / Flashlights - For many NDT applications including: UV Non-Destructive Testing (NDT) such as Dye Penetrant Inspection (DPI), Liquid Penetrate Inspection (LPI), Penetrant Testing (PT), Magnetic Particle Inspection (MPI), Crack & Weld UV Inspection, UV Leak Testing, Purity Control, DNA Based Tracer Fluorescent Liquids (e.g. SmartWater™ Detection), Sanitation, Crime Scene Investigation, Forensics, Hotel Inspections, Art verification & restoration and more.

See our full range of Labino UV Lighting for DPI, LPI, MPI & DP NDT Testing below:

Need Help Choosing a Light?

We know it can be difficult selecting the optimum UV LED Light with so many models & options available.  

See our handy guides below or feel free to contact us.

Dye Penetrant UV Inspection Light (DPI) Labino MB 3.0 UV LED Inspection Light MPI Dye Penetrant Testing with Athena Spray accessory

DPI - Dye Penetrant Inspection Principles & choosing the correct inspection UV Light for your NDT testing needs.

Dye Penetrant Inspection (DPI) is used to determine an items conformity, productivity, safety & can be used for checking for fractures & cracking of ferromagnetic materials.  A widely used NDT Inspection method for initial visual inspection looking for surface-breaking defects in all non-porous materials (metals, plastics, or ceramics).


A liquid dye penetrant may be applied to all non-ferrous materials and ferrous materials, although for ferrous components magnetic-particle inspection is a preferred NDT method often used for its subsurface detection capability.  DPI & LPI is used to detect casting, forging and welding surface defects such as hairline cracks, surface porosity, leaks in new products, product conformity & safety and to detect fatigue cracks on in-service components.


 Dye Penetrant Inspection (DPI Testing) is used throughout the NDT industry as a quick & easy NDT inspection method in a variety of sectors including aerospace, automotive, oil & gas, structural steel, turbines & product conformity to inspect a wide range of products and equipment such as engine, suspension and braking system components, castings, forgings and welds.

One of the main advantages of dye penetrant inspection is that it can give an immediate indication of defects and abnormalities when using UV fluorescent dyes & a UV Inspection Light at 365nm wavelength with basic NDT knowledge & training, rather than more expensive inspection methods for an initial inspection.  If defects are located, further Ultrasonic Testing can be used, but it's a good, low-cost initial indicator of an issue.

Our Labino MB 3.0 with Athena Spray can attachment allows for easy use of fluorescent dyes for wet method DPI using UV light.

We have a very wide range of UV Lights to choose from such as MPXL Bulb or LED technology, mains operated, portable battery operated, combinations of both, hand-held, bench mounted, in varying cases and intensities etc.


All offer instant or near instant start-up times, with no pre cooling etc.  Can be switched off and back on instantly & all operate with no external fans making them lighter and quieter, very useful in damp or dusty environments and require less maintenance.


  • They will still stay cool to the touch, especially useful in confined spaces. 

  • None of our lamps are affected by magnetic fields.

  • The battery models are fitted with current regulators to keep intensities stable when the battery power fades.

Contact us for any advice required on selecting the optimum UV light for your application.

Uncover Hidden Defects with Dye Penetrant Inspection

Dye penetrant inspection is a reliable and effective method for non-destructive testing.  It uses a UV light with a 365nm output to detect small cracks, porosity, and other surface flaws.

 A fluorescent dye penetrant is applied to the surface of the material and then allowed to settle into any flaws or imperfections as per your operating procedures.

After the penetrant is removed, a UV light can be used to visualize any flaws that were not visible to the naked eye.


This method is ideal for detecting small surface flaws and is a cost-effective way to ensure quality products.

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