Frequently Asked Questions

No. All of our filter and dichroic designs are very angle-sensitive.  Our emission filters are designed for a zero-degree angle of incidence (AOI) and dichroics are designed for a 45-degree AOI (unless otherwise specified).  Changing this angle will drastically shift the spectral performance of the part.

In most cases, this is not recommended. Our ET emission filters are made on a different type of glass than excitation filters and ensure image registration between different filter cubes.

In most cases, this is not recommended. Our excitation filters are made to block all light from 300-1000nm or higher outside of the bandpass. Most of our emission filters do not block light that far out of the transmission band and therefore might pass some unwanted light from your light source to your sample. More importantly, this unblocked excitation light will then be transmitted to the detector.

Yes, we do recommend an excitation (laser clean-up) filter. Few lasers are truly monochromatic. Gas lasers typically emit several discrete wavelengths and the blocking provided by AOTFs is often insufficient to prevent laser noise in the emission channel. Many laser diodes can have significant bandwidth and should be treated as a broadband source. Also, because laser illumination is very intense, relatively low levels of laser light can dramatically affect the signal/noise ratio of a fluorescence image.

Yes, an excitation filter is required. The output of LED light sources is not monochromatic and instead has a Gaussian-shaped spectral emission profile. The “tails” of this LED emission often extend >40nm from the peak wavelength and must be excluded from the passband of the emission filter. An excitation filter will block these unwanted wavelengths and transmit only the desired wavelengths to your sample.

Yes, the correct dichroic (or polychroic) mirror selection is very important. The job of the dichroic mirror is to reflect the excitation light to the sample and transmit the emission light to the detector.

Yes. We offer filters to fit all commercial microscopes and home-built systems. Please provide the model of the instrument you will be using to ensure that you receive filters of the correct size. If you are using a home-built system please specify the dimensions of each component of the set including any thickness constraints you may have.

AT filter sets are the perfect choice for routine fluorescence detection and assays, and for most applications requiring accurate color discrimination and excellent out-of-band blocking.

ET filter sets are our highest quality option; they have zero-pixel-shift image registration, and are necessary for applications requiring the highest possible signal intensities.

Yes, Chroma produces optical filters designed for UV and deep-UV wavelengths (below ~380 nm). However, it’s important to note that most commercial microscopes are not optimized for UV transmission.

The internal lenses and optical components in many microscope models are made from glass or other materials that absorb a large portion of light below 380 nm, resulting in poor UV throughput. To effectively work with UV excitation, these internal optics typically need to be replaced with UV-transmitting materials such as quartz to achieve proper performance and efficiency.

No, it does not. The price shown with each set includes the filters only. Filter cubes and sliders have their own product numbers. When you order a filter set and cube together we will assemble them for you at no additional cost.

Please see our Filter Cubes and Sliders page for a list of the holders that we carry and their prices.

Disclaimer: We provide the assembly steps below for general reference use only. Installation procedures may vary depending on your microscope or cube design. Chroma Technology assumes no responsibility for damage resulting from improper installation or use. For detailed product-specific instructions, please refer to your equipment manufacturer’s documentation.

Follow these general steps for assembling a filter cube:

1) Gather tools: filter cube, retainer rings, exciter and emitter filters, dichroic mirror, spanner wrench, screwdriver.

2) Disassemble the cube: remove screws and separate the halves.

3) Remove the dichroic clamp: remove screws and clamp.

4) Install the dichroic mirror: ensure the reflective surface faces the excitation filter/light source; secure with the clamp.

5) Reassemble the cube halves and tighten screws.

6) Install the excitation filter: the arrow faces the specimen (toward the inside of the cube and away from the light source). The retainer ring shoulder faces outward and the retainer ring should be above the filter. Be careful installing the ring to avoid cross threading. Tighten the retainer ring gently with a spanner wrench.

7) Install the emission filter: the arrow faces the specimen and detector side (toward the inside of the cube and away from the detector/eye. The retainer ring shoulder side faces outward and the retainer ring should be above the filter. Be careful installing the retaining ring to avoid cross threading. Tighten the retainer ring gently with a spanner wrench.

Your filter cube is now ready for use.

These are our catalog filter sets mounted in microscope cubes that have been returned to Chroma for various reasons. These filter sets in cubes have been used minimally or not at all. They are not defective and are inspected and cleaned before being listed on our website. They are substantially discounted and are in excellent condition.

Yes, they are.

Please see our Warranty Information for more details.

Our sputtered filters are designed to perform reliably across a wide temperature range. You can view the complete temperature specifications on our Durability & Environmental Specifications page.

Chroma’s sputtered filters are engineered for exceptional long-term stability and performance. Each filter is designed to meet rigorous environmental and durability testing in accordance with relevant ISO and MIL specifications. Under normal operating conditions, performance degradation is virtually nonexistent and every sputtered filter is backed by Chroma’s industry-leading warranty to ensure reliable operation for the life of your instrument.

Laser damage thresholds vary by coating design and spectral region. General guidance can be found in our Durability & Environmental Specifications page. Please note that filters using metallic coatings or operating in highly absorptive wavelength ranges may exhibit lower LDT values.

There are a number of assays in existence that were originally designed for use in spectral unmixing systems, rather than for general immunohistochemical (IHC) staining. These systems rely on the measurement of the entirety of the fluorescence emissions of all fluorochromes present in the sample. These measurements are then evaluated by computer-driven algorithms to the published fluorescence properties of the fluorochromes present. This allows these spectral unmixing systems to “separate” fluorochrome signals that would typically exhibit a large amount of overlap (i.e. GFP and YFP or their analogs).

Please note that these assays can pose issues when used in general IHC because the fluorochromes used can often be inseparable without the use of spectral unmixing algorithms. Traditional IHC systems typically separate only 4–5 fluorochromes reliably. Using more can lead to overlapping signals and reduced clarity.

If your application requires a more specialized configuration or a filter set tailored to your assay, please follow our Request for Quote (RFQ) process to explore a custom design with our team.

We recommend first checking our Spectra Viewer to see if your fluorochrome is included. We’re continuously expanding this database to include additional dyes and spectral data. However, many historically used or specialty fluorochromes lack commercially available fluorescence information. For those not listed in our Spectra Viewer, we suggest consulting primary literature sources or reputable online databases.

Once you’ve located fluorescence data for your fluorochrome, you can upload and view it via the My Data tab in the Spectra Viewer. If you’d like to see that fluorochrome permanently added to our database, you may submit a request through the Submit Your Spectrum link found in our Spectra Viewer modeling tool.

Yes!  Because of the multiplexing typically employed in flow cytometry, you’ll want to use filters that are fully blocked out-of-band up to about 900nm, which is the detection limit of most PMTs. Typically, almost all of our excitation filters and many of our emission filters will work well in these applications. If you do not see what you need please contact us at sales@chroma.com. We make many other parts that are not yet published on the website. 

We simply need to know the wavelength range that you want the filters to transmit, the wavelength range of the excitation light (typically laser or LED), and the size of the desired filter.

If your system requires dichroic mirrors for an angle other than 45 degrees please contact us, we can provide those as well.

Yes. We regularly manufacture optical components in a wide range of custom sizes, shapes and thicknesses. Our extensive inventory and flexible manufacturing processes mean that many standard designs can be modified to your specifications with minimal adjustment. If your required size isn’t listed, please Request a Quote with your specifications and our team will confirm feasibility and provide pricing.

Please visit our Quote Request form, review the full instructions at the top of the page, and submit your requirements. Our team will respond to your inquiry within one business day.

For a detailed checklist and instructions, please visit our Quote Request form.

1) Visit chroma.com

2) Click Order from Quote at the top right of the page.

3) Enter the email address associated with the quote and the quote number.

4) Click Find.

5) Review your items, add them to the cart, and proceed to checkout.

6) Enter your shipping and payment information to complete your order.

For any order updates — including cancellations, changes, or status inquiries — please contact the Customer Service Representative listed on your order confirmation, or email orders@chroma.com.

Include your Chroma Sales Order (SO) number or purchase order number along with a brief description of your request.

If your order was placed by credit card through our website, please note that certain changes may be limited for security reasons. In some cases, we may ask you to resubmit your payment information to complete the update.

Your order confirmation will tell you the day your order is scheduled to ship from Chroma. It will also tell you the shipping method we intend to use. Our standard shipping method in the US is two business day service, but overnight service is also available upon request. Orders that are leaving the US are shipped with international priority service, which normally takes 2-3 business days.

Please contact us at returns@chroma.com and tell us which part you need to return. Our normal process is to credit you for returned items and to have you place a new order for the replacement parts. We need to know the original purchase order number or Chroma sales order number (both are found on the sales order confirmation email/fax) and which part you wish to return and why, so we may provide you with an RMA number to send it back. Upon receiving this number, we ask that you fill out our RMA form and follow the instructions provided. You can start the return process by submitting the RMA request.

If you are using a purchase order from your company or institution please email this to orders@chroma.com or fax it to 802-428-2525.  If you are placing a credit card order it is best to go to our website here:  https://www.chroma.com/cart .  You can order from a quote online via the chroma.com/cart page and then click the blue button to add items from a quote.  Enter the quote number and email address to which the quote was sent.

When placing an order, please be prepared to provide ALL of the following items:

• Purchase order number
• Billing address
• Shipping address
• Buyer contact
• Destination contact (if different)
• Item/part number
• Item/part description
• Microscope make and model or part size
• Any special instructions (i.e. mounting changes)
• Quote number if applicable

Having this information on hand will ensure speedy processing and reduce the potential for error.

We want every customer to be happy with their purchase.  Therefore, we have a one-year full satisfaction guarantee on all catalog filters.  If you purchase items that do not work for your application contact us at returns@chroma.com. We help you arrange to return your parts and get you what you need.

For more information, please refer to our Filter Warranty and Return Information pages.

We offer a lifetime warranty against manufacturer defects for all catalog sputtered filters, a five-year warranty for catalog metal sputtered filters, and a three-year warranty on other catalog filters. For full details and more information on all parts please visit our Warranty Page.

The first confirmation is an automated acknowledgment of the information submitted on the website. The second is your order confirmation. This is generated after a customer service representative processes your order. This second confirmation contains your customer service representative's name and contact number, your shipping preference, your estimated ship date, and your Chroma Sales Order Number. Please reference this number when making any order inquiries.

Option 1: Search for the part number found on the filter holder. We have hundreds of available spectra to view online. Please note that the spectra you view online may not directly reflect the exact optic you are holding, though it will be very similar.

Option 2: Contact sales@chroma.com and provide the number found directly to the right of the upward-facing arrow on the filter ring, called our lot number. We can use that number to provide the measured spectra for your specific part.

If you are holding a Chroma-mounted filter cube we can usually provide spectra for all the optics contained within, provided it has not been modified. For a cube, set lot numbers are denoted as C-##### and can be found on the side of the filter cube.

Our autofluorescent plastic slide sets are only available as a set.

Please note because we do not alter or dictate the materials used in the construction of the autofluorescent plastic slides, we are unable to provide any support in their use. We cannot make any guarantees about the substances these slides are manufactured with, nor what their emission properties are.

For more information on our autofluorescent slide set please visit our blog post.

Please note because we do not alter or dictate the materials used in the construction of the autofluorescent plastic slides, we are unable to provide any support in their use. We cannot make any guarantees about the substances these slides are manufactured with, nor what their emission properties are.