Optical Filter Terminology Decoded

Understanding the terminology for describing optical filters is crucial for communicating the specs and requirements for these optical system components.

In this newsletter, we're breaking down some of the most essential terms to know. For more in depth coverage, download our Handbook of Optical Filters for the full glossary and guide to using optical filters.

Now let's start by breaking down some of the most important optical filter specs:

Cut-on: The wavelength at which a filter transmits 50% and transmission is increasing.
Cut-off: The wavelength at which a filter transmits 50% and transmission is decreasing.
Center Wavelength (CWL): The CWL is the arithmetic mean of the cut-on and cut-off of a filter.
Bandwidth (FWHM): The width of the band from cut-on to cut-off. Otherwise known as full width at half of maximum transmission.

Longpass (LP): Longpass filters transmit wavelengths longer than the cut-on wavelength and block shorter wavelengths.
Shortpass (SP): Opposite to longpass filters, shortpass filters transmit wavelengths shorter than their cut-off point, blocking longer wavelengths.

Blocking Level: A measure of the out-of-band attenuation of an optical filter over an extended range of the spectrum. The attenuation level is often defined in units of optical density.
Blocking Range: The range of wavelengths over which an optical filter maintains a specified blocking (attenuation) level.

Want to know more?

There's a wide range of terms and concepts when it comes to working with optical filters.

To gain a solid understanding, download our Handbook of Optical Filters to get a reference you can trust in your work.

Get the Handbook of Optical Filters

🗓️ Upcoming Photonics Trade Shows

Biophysical Society

February 10th - February 14th, 2024

Philadelphia, PA

The annual Biophysical Society meeting is a great opportunity to connect with others in the field as well as attend symposia and workshops to gain a glimpse into the future of biophysics research.

We'll be there in booth # 619 ready to show you how we can help further your research with optical filters designed specifically for your application.

Molecular & Precision Med Tri Con 2024

March 26th - March 28th, 2024

San Diego, CA

For over 30 years, Precision Med Tri-Con has gathered international experts to collaborate and innovate in diagnostics and precision medicine. This year's programs include AI in medicine and diagnostics, spatial biology, single-cell multiomics, and much more.

Come say 👋. We'll be in booth #217 ready to discuss the ways that optical filters can be used to further diagnostics and precision medicine research.

Optical Filter Fun and Games

Looking for a fun little challenge? Then give our optical filter crossword a try. We think the optics related clues are just the right difficulty.

See how many you can complete, and then share it with your friends, coworkers, and colleagues to see who can get the most.

We'll even give you an advantage. If you need an extra hint for #13 down, just remember "Chroma" 😁

Complete the Crossword Puzzle

Product Spotlight: Colorimetry Filters

Discover unmatched color measurement accuracy with our colorimetry filters for color matching applications across various industries including:

📱 Electronic Displays

🚗 Automotive

✈️ Aerospace

💡 Lighting, LEDs, & Illumination

🎨 Paint, Paper, and Textiles

Customized for Your Unique Requirements

We design and manufacture filters tailored to your specific needs. Whether you need filters matching the Standard Observer functions or Customized functions, we have the perfect solution for you.

Advantage of Opting for Customized Filters:

✅ Enhanced Accuracy: Tailored filters provide a closer match to your unique application, improving the accuracy and reliability of your color measurement process.

✅ Seamless Integration: Custom filters designed for your specific light source or detector allow for seamless integration into your existing measurement setup.

✅ Application-Specific Solutions: Our team works closely with you to develop solutions that address your unique industry and application needs.

Chroma offers CIE filters as part of our standard catalog filter products. Our catalog CIE filters feature an f’< 5.

We also have the ability to match any design or variation on these standards to bring your particular optical system closer to perfect color accuracy.

Contact us for customized colorimetry filters for your optical system. We can customize to match your detector response function and light sources.

In addition, we have a large inventory of filters and a knowledgeable staff ready to help you find or design a filter to meet your specific needs.

Explore Our Colorimetry Filters

Chroma Newsletter - February 2024