{"version":"1.0","provider_name":"","provider_url":"https:\/\/lightingrecipe.com\/zh","author_name":"LRS Admin","author_url":"https:\/\/lightingrecipe.com\/zh\/author\/77026pwpadmin\/","title":"How to Measure Light Correctly? -","type":"rich","width":600,"height":338,"html":"<blockquote class=\"wp-embedded-content\" data-secret=\"GKk46i567F\"><a href=\"https:\/\/lightingrecipe.com\/zh\/how-to-measure-light-correctly\/\">\u5982\u4f55\u6b63\u78ba\u6e2c\u91cf\u5149\uff1f<\/a><\/blockquote><iframe sandbox=\"allow-scripts\" security=\"restricted\" src=\"https:\/\/lightingrecipe.com\/zh\/how-to-measure-light-correctly\/embed\/#?secret=GKk46i567F\" width=\"600\" height=\"338\" title=\"How to Measure Light Correctly? &#8212; \" data-secret=\"GKk46i567F\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" class=\"wp-embedded-content\"><\/iframe><script type=\"text\/javascript\">\n\/* <![CDATA[ *\/\n\/*! This file is auto-generated *\/\n!function(d,l){\"use strict\";l.querySelector&&d.addEventListener&&\"undefined\"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!\/[^a-zA-Z0-9]\/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret=\"'+t.secret+'\"]'),o=l.querySelectorAll('blockquote[data-secret=\"'+t.secret+'\"]'),c=new RegExp(\"^https?:$\",\"i\"),i=0;i<o.length;i++)o[i].style.display=\"none\";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute(\"style\"),\"height\"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):\"link\"===t.message&&(r=new URL(s.getAttribute(\"src\")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener(\"message\",d.wp.receiveEmbedMessage,!1),l.addEventListener(\"DOMContentLoaded\",function(){for(var e,t,s=l.querySelectorAll(\"iframe.wp-embedded-content\"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute(\"data-secret\"))||(t=Math.random().toString(36).substring(2,12),e.src+=\"#?secret=\"+t,e.setAttribute(\"data-secret\",t)),e.contentWindow.postMessage({message:\"ready\",secret:t},\"*\")},!1)))}(window,document);\n\/\/# sourceURL=https:\/\/lightingrecipe.com\/wp-includes\/js\/wp-embed.min.js\n\/* ]]> *\/\n<\/script>","description":"For lighting designers using spectrometers (e.g., devices like the In. Licht Ultra), measurement distance impacts accuracy \u2014 and determines whether you&#8217;re capturing the light source itself, ambient\/task lighting, or human-centric lighting. What Are You Measuring? 1) Direct Light (Source Measurement) Key metrics to measure include: \ud83d\udd39 Correlated Color Temperature (CCT) \ud83d\udd39 Spectral Power Distribution (SPD) \u2014 including dominant wavelength (\u03bbd), peak wavelength (\u03bbp), and peak intensity (\u03bbpv) \ud83d\udd39 Color Rendering Metrics \u2014 CRI (Ra and Re), and TM-30 (Rf and Rg) \ud83d\udd39 Flicker \u2014 flicker frequency, flicker percentage, flicker index, and Stroboscopic Visibility Measure (SVM) \ud83d\udd39 SDCM (MacAdam Ellipses) \ud83d\udd39 Chromaticity Coordinates (x, y) and blackbody deviation (Duv) \ud83d\udd39 Blue Light Hazard Ranking (RG) Room Condition Requirements 1. Dark or Controlled Lighting Environment \ud83d\udd39 Ideally, perform measurements in a dark room or one with minimal ambient light to avoid stray light interference. \ud83d\udd39 If not possible, use black matte surfaces around the test area to reduce reflections. 2. Avoid Reflective Surfaces \ud83d\udd39 Remove or cover any shiny or reflective materials near the light source or sensor. 3. Measurement Angle \ud83d\udd39 Hold or position the sensor perpendicular to the emitting surface of the light source. 4. Measurement Distance \ud83d\udd39 Keep within a 10\u201350 cm range for general light source characterization. \ud83d\udd39 The \u201c10\u201350 cm\u201d distance is a commonly used practical guideline in lighting measurement practice, rather than a strict requirement defined by formal standards. \ud83d\udd39 For photobiological safety (Blue Light Hazard Ranking, RG), follow IEC\/EN 62471: For General Lighting Service (GLS) lamps, evaluate safety at the distance where the source emits 500 lux, and no closer than 200 mm. \ud83d\udd39 Always maintain a consistent, fixed distance for repeatability. \ud83d\udd39 Ensure the sensor\u2019s field of view fully captures the emitting area. \ud83d\udd39 Avoid shadows, obstructions, or ambient stray light during measurements. 2) Ambient \/ Task Lighting This refers to general lighting in a space or light provided for a specific task (like reading or working). Key Metrics to measure include: \ud83d\udd39 Illuminance (lux) \ud83d\udd39 Correlated Color Temperature (CCT) \ud83d\udd39 Color Rendering Metrics \u2013 CRI (Ra and Re), TM-30 (Rf and Rg) \ud83d\udd39 Flicker \u2013 Flicker frequency, flicker percentage, flicker index, and Stroboscopic Visibility Measure (SVM) Room Condition Requirements \ud83d\udd39 Ensure normal occupancy conditions (e.g., curtains\/blinds as usual) \ud83d\udd39 Horizontal Surface (Desk\/Workplane): Height \u2248 0.8 m (typical tabletop) \ud83d\udd39 Vertical Surface (Whiteboard\/Wall Art): Position sensor perpendicular to the wall \ud83d\udd39 Take multiple readings and average the results for accuracy Based on the WELL Building Standard v2 \u2013 Feature L02: Visual Lighting Design To meet illuminance thresholds, the project must refer to one of the following recognized standards: \ud83d\udd39 IES Lighting Library \u2013 Lighting Applications Standards Collection \ud83d\udd39 EN 12464-1:2021 or EN 12464-2:2014 \ud83d\udd39 ISO 8995-1:2002(E) (CIE S 008\/E:2001) \ud83d\udd39 GB50034-2013 \ud83d\udd39 CIBSE SLL Code for Lighting WELL Performance Verification Conditions To ensure compliance, testing must be conducted under these controlled conditions: \ud83d\udd39 Nighttime measurements only \u2013 to eliminate daylight interference \ud83d\udd39 Supplemental lighting, if present, must be turned on and positioned on the work surface in typical usage configuration \ud83d\udd39 Each sample must be taken on the horizontal plane, with the device aperture facing upward \u26a0\ufe0f Important: Ensure the shadow of the human does not fall on the device aperture during measurement Tips: Use In. Licht Ultra\u2019s PDF Report for WELL Submission In. Licht Ultra automatically generates detailed PDF reports that include all required measurement data. These PDF reports can be used directly as supporting documentation for WELL Performance Verification under Feature L02 and other light-related criteria. 3) Human-Centric Lighting Key Human-Centric Metrics to measure: \ud83d\udd39 Circadian Action Factor (CAF) \ud83d\udd39 Equivalent Melanopic Lux (EML) \ud83d\udd39 Melanopic Equivalent Daylight Illuminance (M-EDI) \ud83d\udd39 Scotopic\/Photopic Ratio (S\/P Ratio) \ud83d\udd39 Circadian Stimulus (CS) \ud83d\udd39 Blue Light Hazard Ranking (RG) Based on WELL Building Standard v2 \u2013 Feature L03: Circadian Lighting Design For Workstations Used During the Daytime Electric lighting must achieve the following thresholds for at least 4 hours (beginning no later than noon) at a height of 18 in (\u2248 45 cm) above the work plane in regularly occupied spaces Standard thresholds: \ud83d\udd39 \u2265 150 EML [136 M-EDI] (1 point) \ud83d\udd39 \u2265 275 EML [250 M-EDI] (3 points) For thresholds with enhanced daylight: \ud83d\udd39 \u2265 120 EML [109 M-EDI] + L05 or L06 (1 point) \ud83d\udd39 \u2265 180 EML [163 M-EDI] + L05 or L06 (3 points) For Residential Units (Dwelling Spaces) In addition to the thresholds mentioned above, the lighting must be dimmable. If automated, it should dim automatically after 8:00 p.m. Measurements must be taken: \ud83d\udd39In living rooms and kitchens at 55 in (\u2248 140 cm) in the center of the room \ud83d\udd39In studio apartments or guest rooms, also test in the center \ud83d\udd39For workstations, at 18 in (\u2248 45 cm) above the work plane WELL Performance Verification Conditions WELL v2 (and later): Take samples at night using only electric light to eliminate daylight influence. Sampling Position: \ud83d\udd39Measure on the vertical plane at 45 cm (18 in) above the work plane, with the aperture facing the direction of gaze \ud83d\udd39Light levels must be measured on the vertical plane at eye level to simulate the light entering the eyes \ud83d\udd39Use a tripod and ensure a stable surface \ud83d\udd39Avoid casting human shadows on the sensor \ud83d\udd39Where no working planes are present , take 4 measurements in the center of the space at 140 cm (55 in) in orthogonal directions. The median value of the four measurements constitutes one sample point. Reporting &amp; Compliance Report the illuminance levels in lux and the spectral power at 5 nm increments from 380 nm to 730 nm. WELL Submission Tip The CSV report generated by In. Licht Ultra includes all required WELL metrics and can be used for WELL Performance Verification."}