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Home /  Support Center /  Knowledge Base /  A21 Bulbs (100 watt equivalent)

What is the difference between the Centric Daylight 5000K and Northlux 5000k bulbs?

What is the difference between the Centric Daylight 5000K and Northlux 5000k bulbs? What is the R9 rating for the Centric Daylight 5000k bulb? Also, do the 5000k bulbs give off a blue hue to them? 

The difference between the CENTRIC DAYLIGHT and NorthLux bulbs is that the NorthLux bulbs are calibrated to the D50 and D65 color standards which may be crucial for certain visual tasks. Both feature 95+ CRI and R9 values of 80+.

The 5000K lamps could certainly be perceived as being blue, especially during evening hours, and compared to incandescent and other warm white LED lamps. 

Here is an article going over some aspects of 6500K lamps, many of which would also apply to 5000K lamps:

Are your NorthLux A19 bulbs flicker-free?

Are your NorthLux bulbs flicker-free, like your Centric bulbs? Also, do you offer a watt equivalence higher than 60, please?

We are happy to confirm that the NorthLux™ 95 CRI E26 A19 LED Bulb for Art & Studio product features the same flicker-free operation as the CENTRIC DAYLIGHT™ Full Spectrum Flicker-Free A19 10W LED Bulbs.

Unfortunately, we do not have a higher-wattage A19 bulb available at the moment. You may want to consider our A21 Bulbs, which are equivalent to a 100W incandescent bulb. 

Do you have 220V-rated bulbs?

I see that all your bulbs are rated 120V, although the tubes are 110-277V. Is it possible to get 220V-rated bulbs? 

We do offer several 220-volt compatible A19 lamps. For example, please see below:

LED Lighting Suggestion for Small Townhome of 1200 sq ft

Could you suggest a type of LED lighting for a small townhome ~ 1200 sq ft? I have 9 led lights in my downstairs and the room takes a pink/peach hue. I have white walls and want everything crisp, but cannot find a good brand or light.

Our high CRI LED lights should be a great fit for your home.

The first step in determining your lighting needs would be to understand the amount of brightness and the number of lights needed. Based on the square footage provided, we ran some quick calculations using our lumen estimation calculator ( which suggests approximately 26,000 lumens as your target brightness level.

​We would further recommend a 3000K color temperature which will provide your residential space with a comfortable but crisp white, light.

Why can you not ship to California?

Unfortunately, the A21 flicker-free products cannot ship to California at this time due to government regulations in the state (California Energy Commission Title 20). The specific issue that makes our bulbs non-compliant is the power factor requirement of 0.7 according to the CEC Title 20 ordinance. Unfortunately, our bulbs have a power factor of 0.6.

We are investigating improvements to our product to make our A21 lamps compliant, and are evaluating the cost-benefit analysis from a production perspective.

Reason for enclosed fixture ratings

What is the reason your A19 bulbs can not be used in enclosed fixtures? Why am I able to use a 60W incandescent bulb, but not your bulbs which are only rated at 10W?

Our 10W A19 lamps may not be used in an enclosed fixture. The reason is that enclosed fixtures do not provide sufficient free airflow to keep the bulbs cool, and may lead to premature failure.

Although LED bulbs emit less heat than incandescent bulbs, they are much more sensitive to heat due to the internal electronics in the LED bulb. An incandescent bulb is essentially made just of glass and a wire element coil (filament). Therefore, although a 60W incandescent bulb may work fine in an enclosed fixture and emit lots of heat, a 10W LED bulb emitting only a fraction of the heat may still be detrimental to the LED bulb because its components are much more sensitive to heat.

Best A19 bulbs for digitizing and photographing paintings and artwork?

I am a painter, and am considering using your NorthLux™ A19 bulbs to take photos of my artwork pieces to showcase on my website and other platforms. I am hopeful that these bulbs will reduce the amount of color correction needed post-capture. Are these the best bulbs for my needs?

Our NorthLux™ A19 lamps do indeed sound like a great option for your painting photography. These bulbs feature 95 CRI and daylight calibrated light output, which means they are perfect for image capture without any loss of color accuracy. Because the light source is fundamentally calibrated to full-spectrum daylight, there should not be any need for white balance or color correction adjustments.

The NorthLux™ A19 lamps are offered in 5000K and 6500K. Although both color temperatures can be considered to be daylight calibrated, 6500K will have a slightly blue hue in line with what you would see from a north-facing window, while 5000K will be more neutral, closer to direct sun. Here is an article going over some additional differences between the two color temperatures. Most camera systems will have a color balance calibration setting that allows for the subtle adjustments that may be needed between these two color points.

Alternatively, our FilmGrade™ 5600K A19 lamps may also be of interest. These lamps are calibrated to 5600K (and 95 CRI, of course), which is a mid-point color temperature between 5000K and 6500K. The 5600K color temperature is calibrated for use in photography, film and TV studios, but can be an equally effective and accurate light source for the purposes of digitizing artwork.

​The A19 / E26 form factor ensures that these lamps will fit in virtually all standard bulb fixtures, so this will give you lots of flexibility and room to try out different positions and orientations to get the optimal set up!

Best bulb for viewing prints and color accuracy?

I am looking for a daylight-calibrated LED bulb that fits into a regular table lamp to view prints. Color accuracy and D50 white balance is crucial. What do you recommend?

Our D50 calibrated, 95 CRI LED lamps sound like a great fit for your needs!

For a basic table lamp with a medium-size (E26) screw base, our D50 5000K A19 LED Bulb for Color Matching (ISO3664:2000) product would be the best fit. This bulb is calibrated to the D50 standard, which would be perfect for print viewing and color accuracy.

[Archived] What is the difference between CENTRIC DAYLIGHT™ 5000K/6500K and D50/NorthLux™?

[ARCHIVED ARTICLE] This article has been archived as of November 2021 due to recent changes in our product specifications. Please see this article for the most up-to-date information on our current offerings. Customers who purchased our lamps prior to 2021 (lamps marked with PN 4005.XX rather than PN 4005C.XX) can continue to reference the archived information below.

Several of our products are listed on multiple product pages for marketing purposes. One major exception is our 10 watt A19 bulb product line, for which we offer the two part number variants for each of the 5000K and 6500K color points:


PN 4005.50: CENTRIC DAYLIGHT™ 5000KPN 4005.D50: D50 / NorthLux™ 5000K


PN 4005.65: CENTRIC DAYLIGHT™ 6500KPN 4005.D65: NorthLux™ 6500K

You will notice that the D50 and NorthLux™ product lines have a "D" prefix in the color temperature designation inside the part number. This signifies that these products are calibrated to the D50 and D65 color standards for color viewing and other vision-critical applications at 5000K and 6500K, respectively.

The CENTRIC DAYLIGHT™ products are also available in 5000K and 6500K, but they are not designed for color viewing applications. Specifically, they have a slightly greener tint (elevated Duv values), which is a closer approximation of the ANSI chromaticity targets for daylight color points.

In short, if you're looking for a lighting solution for a professional or color-critical application, we recommend the D50 / D65 designated NorthLux™ lamps. On the other hand, if you're using the lamps for indoor lighting such as light therapy, the CENTRIC DAYLIGHT™ lamps will be a great option.

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