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05 Jun 2025in Forensics examination

What Is a Video Spectral Comparator and Why Forensic Experts Rely on It

Igor Duboiski

Forensic Expert, Regula

In an age where document fraud is more sophisticated than ever, forensic experts and security professionals need tools that provide high-end technologies, efficiency, and examination accuracy.

One of the most powerful tools in modern document examination is the video spectral comparator. In this article, we’ll take a closer look at this advanced forensic device.

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What is a video spectral comparator?

Let’s unpack the term video spectral comparator step by step, because each word tells us something about what the device does:

Video refers to the live imaging capability. A video spectral comparator captures high-resolution real-time video of the document being examined. Unlike traditional static imaging, the live feed allows forensic experts to manipulate the document (zoom, rotate, change light settings) and instantly observe effects under different lighting conditions. It's like looking through a digital microscope—what we see is dynamic and can be analyzed in real time.

The word spectral relates to the light spectrum, including ultraviolet (UV), visible, and infrared (IR) light, as well as optics, which is the camera and filters.

The light spectrum includes ultraviolet, visible, and infrared light

Video spectral comparators used in forensics are equipped with different types of white, ultraviolet, infrared, and narrowband light sources. The more advanced the video spectral comparator is, the greater the number and variety of light sources it features and the more wavelengths it includes

Different materials comprising the document (like paper, inks, and fibers) react differently under various wavelengths of light. By illuminating a document with different light sources, experts can verify the authenticity of banknotes or documents by visualizing security features like watermarks, security threads, microprinting, fluorescent patterns, and holograms, and by determining printing techniques. The device can also reveal hidden or altered information, such as erasures, altered handwritings or printed texts, and morphed photos.

Finally, the term comparator emphasizes comparison—a key function of the device. It is particularly valuable in forensic science, where, based on a comparison between genuine/reference samples and questioned documents or banknotes, it is possible to determine their authenticity. It is done by comparing paper, inks, fonts, types of printing, glowing patterns, and embedded security features under various lighting conditions and magnification.

Again, a video spectral comparator is a device that captures live images of an object under various spectra of light, and contains different tools to compare the obtained images and data with references.

Who needs video spectral comparators?

The primary users of video spectral comparators are:

  • Various forensic laboratories.

  • Border control, immigration, and law enforcement agencies.

  • Central banks and financial institutions.

  • Printing houses and manufacturers.

Other users that can benefit from using video spectral comparators are auction houses and museums. Video spectral comparators feature strong magnification, different types of white, UV, IR, and narrowband light sources, spectrometers, 3D reconstruction modules, and powerful optical systems that are helpful for examining art objects, paintings, and handwritten and printed documents.

Read about how the Regula 4307 video spectral comparator helped authenticate a previously unknown Frida Kahlo painting.

How is a video spectral comparator used in forensic examinations?

A video spectral comparator is a professional device that combines many tools widely used in forensic science under one roof. It features a bunch of light sources, advanced optics, a combination of optical and digital magnification, a spectrometer, hyperspectral and 3D reconstruction modules, RFID and barcode readers, etc.

Examination of intaglio printing under different zoom rates

US dollar of the 2013 series. Example of examination of intaglio printing as a part of comprehensive authenticity verification of banknotes

Examination of letterpress printing technique under different zoom rates

Passport of the United Kingdom of Great Britain and Northern Ireland issued in 2020. Example of examination of letterpress printing technique as a part of a comprehensive authenticity verification of travel documents

Example of examination of intersecting strokes in different display modes

Example of examination of intersecting strokes. The detection of sequences of intersecting strokes can help to reveal blank paper fraud

If you are interested in learning more about 3D reconstruction in forensics, then don’t hesitate to check What Is 3D Reconstruction and What Tasks Does It Solve in Forensics?

Example of detection of alterations made by etching under different light sources

Example of detection of alterations made by etching. The use of varied light sources, integrated in video spectral comparators, helps to reveal the original content

A video spectral comparator is the ultimate solution for almost all forensic tasks that deal with banknotes and travel documents of varied types, as well as printed and handwritten documents, books, and even paintings and art objects. Its functions, tools, and light sources are tailored to meet the requirements of modern forensic science.

It even contains reference samples…

Again, the term “comparator” derives from the verb “to compare”—usually, the comparison is performed against a genuine reference sample. But what if an examiner lacks a physical specimen? In such cases, there is no better remedy than using Information Reference Systems (IRSs), as these digital catalogs contain high-quality images of travel and vehicle documents, banknotes and coins, and close-up images of their security features. It has everything necessary to conduct a comprehensive analysis in the absence of a physical specimen of a document or banknote: images under different light sources (including Anti-Stokes luminescence), visualized security features in JPG and GIF formats, and magnetic cards.

What to bear in mind

A video spectral comparator is a professional device that requires special knowledge in forensic science, as well as the skills to operate and maintain it.

The good news is that Regula can help with both requirements.

For example, let’s take an operation. After the device is delivered, our training specialists are happy to conduct offline training, all the way from unpacking and setting up the device to detailed explanations of how to conduct advanced forensic tasks. Extensive training takes 2-3 days, depending on the customer’s needs.

If users lack some knowledge, Regula has specialized training courses on document and banknote authentication. These courses are designed for employees and officials across industries: law enforcement, aviation, healthcare, customs and migration, banking and finance, and many more. The instructors are forensic examiners with more than 20 years of experience in the field.

Get to Know Regula Comparators

The most advanced video spectral comparators to date.

What makes Regula video spectral comparators extraordinary?

Currently, our product line includes four video spectral comparators. All of Regula’s solutions—hardware, software, and IRS, are developed entirely in-house. It’s a collaborative effort between experienced engineers, talented programmers, and skilled production teams that ensures everything works seamlessly together.

Besides that, forensic experts are deeply involved at every stage of product development. From designing new features to configuring software and testing devices, their hands-on experience ensures each solution is practical, reliable, and ready for the field.

Plus, there are plenty of game-changing features that open up even more possibilities for detailed and accurate document examination, while making it easy and comfortable for users:

  • All-LED lighting
    Regula has fully embraced LED technology—even for UV light. That means better energy efficiency, longer-lasting components, and minimal heat. Nearly all of our video spectral comparators use 100% LED lighting.

  • One app to rule them all
    Regula Forensic Studio (RFS) is the only program for all Regula forensic devices. It works across platforms and lets you control equipment, take measurements, process images, generate reports, and even build custom automations with scripting. 

  • Built-in RFID chip reader
    Every model comes with an RFID module to read and verify electronic documents. It checks chip integrity and reads the embedded data.

  • Anti-Stokes fluorescence detection
    Thanks to special wideband IR light (970–990 nm), these devices can reveal hidden security features printed with Anti-Stokes inks—used in passports from the US, Austria, Denmark, Germany, Greece, Iceland, Switzerland, and others.

  • Hyperspectral imaging
    Hyperspectral imaging is great for spotting alterations or uncovering the original content of documents, banknotes, or even historical texts without damaging them.

  • 3D reconstruction
    This feature builds a 3D model of the document’s surface, helping you see fine details like overlapping signatures or printed text layered over handwriting.

How to make the right choice

A video spectral comparator is a professional device that conducts crucial document and banknote examination. Document experts are lucky in one regard—few areas of forensic science have such a versatile tool at their disposal. A video spectral comparator is like a Swiss Army knife, capable of handling almost every challenge in document analysis.

Modern comparators have a wide range of functions, including a built-in computer, spectrometer, and hyperspectral and 3D analysis modules.

To better understand the Regula video spectral comparator product line, read the article Choose Your Fighter: Picking the Perfect Video Spectral Comparator or contact our sales team directly. They will be more than pleased to answer your questions or conduct a dedicated presentation.

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