Publish Time: 2025-10-17 Origin: Site
When you look at an airport X-ray baggage scanner image, you may notice orange, blue, and green areas. But what do these X-ray scanner colors mean?
The X-ray baggage scanner color code (also called the colour code) helps security operators distinguish different material categories. In many dual-energy systems, orange typically represents organic materials, blue indicates high-atomic-number materials such as metals, and green represents intermediate materials or certain overlapping material combinations.
Understanding these colors helps explain how baggage screening systems interpret different materials, although the exact color mapping depends on the scanner and its display settings.
Orange: Usually represents organic materials such as clothing, food, paper, and many plastics.
Blue: Commonly indicates metals and other materials with relatively high effective atomic numbers.
Green: Often represents intermediate materials, such as certain glass and aluminum objects, or mixed material regions.
Dark or Opaque Areas: May indicate strong X-ray attenuation, where the scanner has difficulty displaying internal details.
Color Coding: Helps operators distinguish material categories, but object identification requires additional image interpretation.
The exact color display depends on the X-ray baggage scanner's imaging technology and software configuration.
Modern dual-energy X-ray baggage scanners use color-coded images to help operators distinguish different material categories.
The three most commonly recognized colors are orange, blue, and green.
| X-Ray Color | Typical Material Category | Common Examples |
|---|---|---|
| Orange | Organic or low-effective-atomic-number materials | Clothing, paper, food, leather, many plastics |
| Blue | High-effective-atomic-number materials | Steel, copper, metal tools, coins |
| Green | Intermediate materials or certain material combinations | Aluminum, some glass, certain inorganic materials |
| Black / Very Dark | Strongly attenuating or poorly penetrated areas | Thick or dense material regions |
Note: These are typical color conventions for dual-energy X-ray systems. Actual colors and thresholds depend on the equipment manufacturer and display settings.
These color classifications are consistent with material discrimination principles described in the EU X-ray color mapping guidelines. The guidelines describe how X-ray systems can distinguish material categories using effective atomic number ranges and color-coded imaging. However, actual color representation may vary depending on the scanner and its display settings.
The baggage scanner colour code is a visual system used to display material differences in X-ray screening images. It is commonly associated with dual-energy X-ray baggage inspection systems, sometimes referred to as XBIS (X-ray Baggage Inspection Systems).
In many systems, orange represents organic materials, blue indicates higher-atomic-number materials, and green identifies intermediate material characteristics. However, scanner manufacturers may use different display palettes and material discrimination settings.
The colors support security screening but cannot independently determine the exact identity or safety status of an object.
Orange is one of the most common colors displayed in X-ray baggage screening images.
In many dual-energy systems, orange indicates materials with relatively low effective atomic numbers, including many carbon-based substances.
Common examples include:
Cotton clothing and fabrics
Food, fruits, and packaged snacks
Paper documents and books
Leather wallets and belts
Many plastic products
For example, clothes, books, and food packages may produce orange-colored regions on the scanner display.
However, orange does not necessarily mean an item is safe or unsafe. Different materials can share similar X-ray characteristics.
Security operators must consider the object's shape, location, overlapping contents, and other image information.
Blue commonly represents metals and other materials with relatively high effective atomic numbers.
These materials absorb X-rays differently from many organic substances, allowing dual-energy imaging systems to assign them a different display color.
Examples may include:
Steel objects
Copper components
Metal keys and coins
Certain metal tools
Metallic parts inside electronic equipment
For instance, a collection of keys may appear blue on a typical dual-energy X-ray display.
However, an electronic device contains multiple materials, so its image may include several colors rather than appearing entirely blue.
Important: Blue indicates material characteristics, not an automatic determination that an object is prohibited.
Green is commonly used to display materials with intermediate effective atomic numbers or certain combinations of materials.
Unlike the simplified explanation that green always means a mixture of organic and inorganic substances, the interpretation is more complex.
Depending on the equipment, green areas may correspond to:
| Material or Condition | Possible X-Ray Representation |
|---|---|
| Aluminum | Often green or an intermediate color |
| Certain types of glass | May appear green |
| Some inorganic materials | May appear in intermediate color ranges |
| Overlapping materials | May produce mixed color information |
The exact appearance depends on material composition, thickness, overlapping objects, and imaging software.
This is why operators should not rely on color alone to identify an object.
Besides material categories, image contrast and X-ray attenuation help explain how objects appear on the screen.
The appearance of an X-ray image depends partly on how much X-ray radiation passes through the inspected object.
Thicker or more strongly attenuating materials generally reduce the amount of radiation reaching the detectors.
However, whether these areas appear brighter or darker depends on the scanner's display mode, contrast settings, and image processing.
| Imaging Factor | Effect on the X-Ray Image |
|---|---|
| Material Thickness | Greater thickness usually increases X-ray attenuation |
| Material Composition | Different elements absorb X-rays differently |
| Object Overlap | Multiple objects can affect the displayed image |
| Display Settings | Brightness, contrast, and color presentation may change |
Therefore, it is not always accurate to say that bright objects are dense and dark objects are light.
Image interpretation must account for the scanner's display settings and material discrimination technology.
Many modern baggage scanners use dual-energy X-ray technology.
Instead of relying only on the overall amount of X-ray absorption, dual-energy systems compare how materials attenuate X-rays in two different energy ranges.
This information helps the imaging software estimate material characteristics, including effective atomic number, and assign display colors. For a more technical explanation, the CSIR dual-energy X-ray material discrimination research describes how X-ray imaging technology can differentiate organic, inorganic, and metallic materials using energy-dependent attenuation and material characteristics.
The basic process involves:
X-rays pass through the baggage.
Detectors measure transmitted radiation.
The system processes measurements from different energy ranges.
Material discrimination software estimates material characteristics.
The scanner displays a color-coded image for operator interpretation.
This process allows security personnel to distinguish broad material categories more effectively than with conventional grayscale imaging alone.
Nevertheless, dual-energy color coding is an aid to inspection rather than a guarantee of precise material identification.
For additional information about scanner technology, explore our X-Ray Baggage Scanner Basics and Features.
An X-ray baggage scanner uses an X-ray generator, conveyor system, detectors, and image-processing software to inspect the contents of baggage.
The inspection process is designed to produce an internal image without routinely requiring the bag to be opened.
The typical scanning process includes six steps:
Baggage Placement: The item is placed on the conveyor belt.
Conveyor Movement: The belt transports the baggage through the inspection tunnel.
X-Ray Generation: The X-ray source directs radiation through the baggage.
Signal Detection: Detectors measure the X-rays passing through the inspected objects.
Image Processing: Software converts detector signals into an inspection image.
Image Review: Trained security personnel evaluate the image and determine whether additional inspection is necessary.
The main components and their functions are summarized below.
| Component | Main Function |
|---|---|
| X-Ray Generator | Produces the X-rays used during inspection |
| Conveyor Belt | Moves baggage through the scanning tunnel |
| Detector System | Measures transmitted X-ray signals |
| Image Processing Software | Produces and enhances the inspection image |
| Operator Display | Presents the image for security screening |
To learn more about the inspection process, read our X-Ray Baggage Scanner Working Principle.
Color coding helps operators distinguish material categories and interpret complex baggage images.
Its main benefits include:
Supporting faster visual interpretation of material differences
Helping distinguish organic and inorganic material characteristics
Improving the presentation of overlapping or complex objects
Supporting image analysis during security inspection
Some scanners also include image enhancement functions, such as contrast adjustment, material highlighting, and alternative display modes.
Even with these features, trained operators must evaluate more than color when making inspection decisions.
No. Although orange, blue, and green are widely recognized in dual-energy X-ray baggage screening, not every scanner uses exactly the same color mapping.
Differences may arise from:
Equipment manufacturer
Single-energy or dual-energy imaging technology
Image-processing algorithms
Display modes and contrast settings
Material discrimination thresholds
Some systems also use additional colors or specialized image enhancement functions.
Therefore, when interpreting a particular scanner image, the manufacturer's operating documentation and training guidance should take priority over general color charts.
On many dual-energy X-ray baggage scanners, orange represents organic materials, blue indicates metals and other high-atomic-number materials, and green shows intermediate materials or certain material combinations. Exact colors vary by system.
No. Orange describes a general material characteristic, not whether an item is safe or permitted. Security personnel consider multiple image characteristics when inspecting baggage.
Areas that strongly attenuate X-rays may appear very dark or opaque in certain display modes. Their appearance also depends on the scanner's imaging and contrast settings.
No. X-ray scanners produce images based on radiation transmission and material characteristics. Object overlap, material composition, and equipment capabilities can affect how clearly contents are displayed.
Clothing does not make an item invisible to an X-ray scanner. However, X-ray image interpretation depends on several factors, including overlapping objects, material characteristics, and the scanner's technical capabilities.
Yes. Security-screening cabinet X-ray systems are generally safe for common electronic devices, including smartphones, laptops, and tablets. According to the U.S. FDA guidance on cabinet X-ray systems, the X-ray dose received during normal security screening does not harm electronic equipment.
No. Different manufacturers and systems may use different color palettes, thresholds, or image display modes. Operators should follow the relevant equipment documentation.
Many organic materials, including tea, shampoo, and some cosmetic products, may appear orange in dual-energy X-ray baggage scanner images. However, their actual appearance depends on composition, packaging, thickness, and scanner settings. Products containing metallic or inorganic components may display additional colors.
XBIS stands for X-ray Baggage Inspection System. In dual-energy XBIS equipment, color coding helps distinguish broad material categories using their X-ray attenuation characteristics. Common display colors include orange, blue, and green, although the precise mapping varies between systems.
Understanding X-ray baggage scanner colors helps explain how modern security screening systems distinguish different types of materials.
In many dual-energy systems, orange typically indicates organic materials, blue represents metals or higher-atomic-number materials, and green is associated with intermediate material characteristics or certain material combinations.
However, colors alone do not identify specific items or determine whether something is dangerous. Reliable interpretation also depends on object shape, material attenuation, image quality, and operator judgment.
At Safeway Inspection System, we provide X-ray security inspection equipment for baggage and parcel screening applications.
Explore our X-ray baggage scanner solutions or contact our team to learn more about equipment features and material discrimination technology.
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