Light Absorption Materials Compared: Thorlabs BKF12 vs. Acktar MetalVelvet
In scientific and engineering fields, the control of stray light is critical. Two standout foil products have established themselves as go-to solutions for reducing unwanted reflections: Thorlabs’ BKF12 Matte Black Aluminum Foil and Acktar’s MetalVelvet Foil. While both serve the same purpose—absorbing light and minimizing reflections—they differ significantly in performance, technical specifications, and suitability for high-precision applications.
BKF12 Matte Black Aluminum Foil – Practical and Versatile
The BKF12 Matte Black Aluminum Foil comes in rolls of 1′ x 50′ (305 mm x 15.2 m) with a thickness of 0.002″ (50 µm). Made of high-quality aluminum and coated with a matte black finish, it effectively reduces glare and stray reflections. This makes it well-suited for laboratories, optical experiments, or shielding light-sensitive areas.
Key performance details:
- Total reflectance (visible spectrum): 3–5%
- Flexibility: Easy to cut, shape, and apply
- Durability: Resistant to corrosion, low outgassing even in vacuum conditions
Overall, BKF12 strikes a solid balance between affordability and performance. It’s a practical choice for many optical setups where minimizing, but not eliminating, reflections is sufficient.
Acktar MetalVelvet – Ultra-Low Reflectance for Extreme Demands
At the high end of light absorption technology lies Acktar MetalVelvet. This material is specifically engineered for ultra-demanding environments such as ultra-high vacuum systems, precision optics, and astronomical instruments.
Its proprietary surface treatment achieves extraordinarily low reflectance values:
- Total reflectance (visible spectrum): typically <1%,
- Absorption: Suppresses both specular and diffuse reflections EUV to FIR
- Stability: Maintains properties under vacuum and high temperatures, with negligible contamination
Because of its performance, Acktar MetalVelvet is the material of choice whenever stray light must be virtually eliminated—such as in astrophysical detectors, laser systems, or high-sensitivity imaging devices.
Reflection Values at a Glance
| Product | Reflectance (visible spectrum) | Highlights |
| BKF12 Matte Black Aluminum Foil | 3–5% | Flexible, corrosion-resistant, UHV compatible |
| Acktar MetalVelvet Foil | <1% | Extreme absorption, scientific-grade precision |
Choosing the Right Material
The decision between BKF12 and MetalVelvet ultimately comes down to application requirements:
- For general lab work and cost-effective reflection reduction, BKF12 is a strong and reliable option.
- For cutting-edge research, precision optics, automotive, astronomical instruments and life science , where every stray photon matters, Acktar MetalVelvet is unmatched.
Both products are excellent in their domains—it’s simply a question of how much light you can afford to let slip through.
Sources:
The use of Acktar coatings yield major improvements in a wide range of products and applications.
Visit the following links to find use cases by categories:
