Temporal Light Artifacts

An undesired change in visual perception induced by a light stimulus whose luminance or spectral distribution fluctuates with time, for an observer in a certain environment.




  • Definition(CIE):Perception of visual unsteadiness induced by a light stimulus whose luminance or spectral distribution fluctuates with time, for a static observer in a static environment.
  • Frequency Range: ~0 – 80Hz
  • Environment: Static
  • Observer (Human): Static
  • Metrics:1. Percent Flicker  2. Flicker Index


Stroboscopic Effect


  • Definition(CIE):Change in motion perception induced by a light stimulus whose luminance or spectral distribution fluctuates with time, for a static observer in a nonstatic environment.
  • Frequency Range:~80Hz – 2kHz
  • Environment: Dynami
  • Observer (Human): Static
  • Metrics:SVM


Phantom Array Effect


  • Definition(CIE):Perception of a spatially extended series of light spots when making a saccade (image transition across the retina) across a light source that fluctuates with time.
  • Frequency Range:~80Hz – 2kHz
  • Environment: Static
  • Observer (Human): Dynami
  • Metrics:X

Visual Merchandising, LED Lighting Solutions-Handheld Spectrometer

MK350S Premium

MK350S Premium is a Handheld Spectrometer with Muli-Functions in itself. It's not only a Spectrometer, but also can be a Quantum PAR Meter, Blue light Detector and Oscilloscope. The

Stand alone Spectral Light meter-Handheld Spectrometer

MK350N Premium

MK350N Premium is a Spectrum Analyzer, LED Meter and Flicker Meter for LED manufacture. Embedded with spectral technology and optimize the LUX measuring range. Overall, the measuring

Compact Spectrometer


UPRtek Compact MK350D is the pocket-Sized spectrometer in the world and released in 2014. It is only 70g and easy to carry. Measurement light units are more than 27, such as CCT, LUX, CRI,



CV600 - All purpose Professional Cinematic and Photographic Light meter. It is not only a Light meter, but also a Color meter, Cine meter and Exposure meter a quicker, more efficient measurements for



PG100N Handheld Spectral PAR meter is focused on achieving the demands of agricultural field. It shows its own advantages of measuring functions ,such as spectrum, PPFD and PFD so that users

Lighting measurement system-Handheld Spectrometer

MK350S Advanced

Advanced MK350S the 1st handheld Spectrometer cross to muti-industrials. It had more than 40 light measurement units which are CCT, LUX, CRI, CIE1976, CIE1931,PPF, CQS, Duv, LambdaP, S/P

LED Test & Measurement-Handheld Spectrometer

MK350N Basic

MK350N Spectrometer is the first portable LED Meter which can be used without a computer for evaluation of artificial light sources, such as LED, OLED and others. In addition, it can easily measure

LED Test & Measurement-Handheld Spectrometer

MK350N Plus

MK350N PLUS is the LED meter for LED Manufacturer. It included more than 40 light measurement units such as CCT, CRI, CIE1931/1976, LUX, TLCI and others. Assist you to discover new busines

What is CRI (Color Rendering Index)?

What is CRI (Color Rendering Index)? It is a metric used to measure the ability of a light to bring out colors in objects (i.e. Color Rendering). Lights with a high CRI rating can make store products look brilliant and vibrant. Other lights with low CRI ratings will make the same products drab and lifeless: Read More

What is CQS (Color Quality Scale)?

Yet another rendering index is the CQS or Color Quality Scale developed by the NIST (National Institute of Standards and Technology), an agency of the United States Department of Commerce. CQS is also aimed at remedying the deficiencies of the CRI (Ra) indexing system. Read More

What is IES TM-30-15?

TM-30-15 is a color rendering index by IES (Illuminating Engineering Society). Like CRI, it uses a sampling of colors and rates each color 0-100 to arrive at an average. However TM-30-15 boasts 99 sample colors as opposed to 14 for CRI (R96a). Comparing more colors means more accurate representation of color rendering capabilities. Read More

What is TLA (Temporal Light Artifacts) ?

An undesired change in visual perception induced by a light stimulus whose luminance or spectral distribution fluctuates with time, for an observer in a certain environment. Read More

What is Flicker Metrics (Percent Flicker, Flicker Index, SVM) ?

This article compares three flicker metrics regarding percent flicker, flicker index and SVM. The comparison includes the definition comes from which organization, the definition of itself, calculation formula and the description of the range. If you want to know more about which products have related measurement functions, please click on the relative products tab. Read More

What is Cosine Correction?

Cosine is a mathematical function used to calculate and specify the characteristics (length & angles) of triangles (Trigonometry). Below right picture is the cosine correction comparison between MK350S Premium and Lambert’s Cosine Law. The ideal value of the red circle was described by Johann Hein¬rich Lambert in 1760 and is called “Lambert’s Cosine Law”. Basically it shows how light intensity changes as the angle of the light changes. MK350S Premium cosine receiver is the blue circle; the optimized cosine and Lambert's cosine law are almost overlapped. It is more in line with international standards for illuminance measurement - JIS AA and DIN B standards and reduced measurement errors effectively. Read More

What is the recommended measuring distance using UPRtek handheld spectrometer?

It depends on users’application needs. Users can adjust the distance of measuring based on their requirements. For example, when a designer sets up the internal lighting and finds out that the light intensity is insufficient in a specific area, the general practices are to increase the numbers of the lights or adjust the installation of height from above to below to make the best display of the whole area. In the same way, you can fix it reversely when lights emit too much intensities. Therefore, users can quantify the light source, get the illuminance value (Lux) with MK350 series handheld spectrometers as well as adjust the numbers and height of the fixtures based on their needs on the current lighting demands. MK350 handheld spectrometers are the best helper to detect the light quality and intensity changes which improve the lighting visual experiences and meet the requirements of the energy saving needs. Read More

Handbook Series

The Grow Light Handbook

Everything thing you need to know to get started on Indoor Farming, PAR meters, and Grow Lights  – history, industry, vertical farming, PPFD, types of lights, photosynthesis and more!

▸ Get it!

About UPRtek

United Power Research and Technology

UPRtek (est. 2010) is a manufacturer of portable, high-precision light measurement instruments; Handheld Spectrometers, PAR meters, Spectroradiometers, Light Calibration Solutions.

UPRtek HQ, R&D and manufacturing are all based out of Taiwan, with Worldwide representation through our certified Global Resellers.

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UPRtek's partner in China, Quelighting Optoelectronics Co., Ltd, and Plant Growth Chamber Manufacturer Ningbo Jiangnan Instrument Factory will attend the 30th International Conference on Arabidopsis Research (ICAR ) which is being held on June 16-21 at Huazhong Agricultural University in Wuhan City, Hubei Province, China.

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