11/14/2016. Exponation AIA Provider Number: Learning Objectives. Course Description. Meters, Metrics and Visual Perception LEDSSMW16-S#1

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1 Exponation AIA Provider Number: Meters, Metrics and Visual Perception LEDSSMW16-S#1 Kevin Willmorth, Lumenique LLC and Tasca Credit(s) earned on completion of this course will be reported to AIA CES for AIA members. Certificates of Completion for both AIA members and non-aia members are available upon request. This course is registered with AIA CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. Course Description Learning Objectives This presentation will explore the issues of metrics, meter use and the connection and disconnect these have with actual visual results. The exploration includes presentation of a concept for a more complete metric representation of lighting qualities, the combines uniformity, color and visual qualities. 1. Understand the use of metrics and their limitations, and how to use them to solve real world issues, while avoiding assumptions about them that lead to issues in application. 2. Understand how meters used to evaluate products and field results work, where they can be relied upon, and when they produce unreliable data. Includes presentation of simple strategies for gaining the best meter results, and what meters on the market today can do for designers. 3. Gain insight into the potential of creating a new metric tool for evaluating products, built from information already available. See how this can be done without manufacturer participation or a single committee meeting, by building a basic spreadsheet based evaluation tool to qualify products. The spreadsheet master will be made available to all who attend. 4. See how visual perception and accommodation to lighting conditions amplifies some problems, while erasing others, and using this to prioritize in the design process. 1

Finding the happy medium between cost and result In this presentation we will Walk through a little background on light metering Review affordable and practical metering approaches

results Look at a method for classifying products based on metered results and catalog data, or both Metrics vs.

2 Finding the happy medium between cost and result In this presentation we will Walk through a little background on light metering Review affordable and practical metering approaches Explore how meters can be used in field application Talk about tools and accessories to improve the metering experience Discuss common metering errors and approaches to improve results Look at a method for classifying products based on metered results and catalog data, or both Metrics vs. Vision The human visual system has zero accuracy cannot be calibrated to a known standard Variable, uncalibrated optical receiver parts with adaptive features that change with age Variable software with subjective perception feature that changes with age 2

Non Linear Perception Human perception of brightness not linear Person to person perception is not uniform Relative Power Level 100 100 97 95 95 92 90 90 89 85 87 84 80 80 81 77 75 74 70 70 71 67

Light Non Linear Visual Performance Response Human response to spectral color balance is not flat Varies by age, health, and individual preference CCT S/P Ratio EVE Factor Perceived Illuminance

3 Non Linear Perception Human perception of brightness not linear Person to person perception is not uniform Relative Power Level Relative Illuminance Measured Light Percieved Light Non Linear Visual Performance Response Human response to spectral color balance is not flat Varies by age, health, and individual preference CCT S/P Ratio EVE Factor Perceived Illuminance (20Fc Base) 2700K K K K K Subjectivity Filter It s too dark in here Wrong, too bright, I can still see you 3

So We Invented Meters Changes observation from subjective (looks good) to objective (numeric value) Allows metric comparison

Survey a lighting condition Verify performance against a product specification Verify performance against a calculated

problems or capture design data Understand more about light in a space Testo 540 What We Meter Illuminance Color and color

4 So We Invented Meters Changes observation from subjective (looks good) to objective (numeric value) Allows metric comparison Between observers Over time Calibration = verifiable accuracy Electrophot 1931 Weston Why Meter Evaluate a product Survey a lighting condition Verify performance against a product specification Verify performance against a calculated prediction Monitor performance over time (color) Track lumen depreciation Evaluate an environment to be lighted Solve problems or capture design data Understand more about light in a space Testo 540 What We Meter Illuminance Color and color characteristics Modulation (Flicker) A wide range of pecific applicable characteristics Brightness (luminance) X-y coordinate Duv shift Etc 4

Data Extrapolated from Readings Color Accuracy CRI Ra and specific R values TM30 Rf and Rg MacAdam Steps from standard center point Visual performance Human factors Energy vs.

5 Data Extrapolated from Readings Color Accuracy CRI Ra and specific R values TM30 Rf and Rg MacAdam Steps from standard center point Visual performance Human factors Energy vs. Power Consistency comparison S/P ratio Horticultural PPFD (Photosynthetic Photon Flux Density) PAR (Photosynthetic Active Radiation) Factors, Approaches and Meters in Use Factoring Required for Visual Response Need to match meter response to human visual response Otherwise, meter is just measuring total energy collected at the photo receptor or cell, whether or not it can be seen 5

Cosine Correction for Illuminance Cosine correction for illuminance

reference or standard Older meters are +/- 10% of any reading Newer meters are

003 in x-y, +/-3% CCT Precision is how tight readings are to one another,

6 Cosine Correction for Illuminance Cosine correction for illuminance measurements Does not provide luminance or spot measurement Lambert s cosine law Accuracy vs. Precision Accuracy is how close a meter will produce a result against a known reference or standard Older meters are +/- 10% of any reading Newer meters are +/- 5% Illuminance, +/-.003 in x-y, +/-3% CCT Precision is how tight readings are to one another, sometimes referred to as repeatability Older meters are +/- 5% Newer meters are +/- 2% Illuminance, +/ in x-y, +/-1% CCT Look for values that are < 50% of accuracy specification Accuracy range: Reading vs. Full scale Full scale is % of max reading (not good) Reading is % of any reading (good) Analog Meters GE DW GE DW GE GE

Essentially Voltmeters and Photocells Silicon Photocell Response Results 1.005 Volt Meter and Silicon Photocell 1.

980 CCT of Light Source 2700 3500 5000 Meter No Filter Green Filter LED Light and Analog Meters Selenium photocell not

Low Cost Digital Meters Diffuser (Cosine Corrector) Photosensor (under diffuser) Gage (Voltmeter w/firmware) Amprobe

7 Essentially Voltmeters and Photocells Silicon Photocell Response Results Volt Meter and Silicon Photocell Green Filter Relative Measurement CCT of Light Source Meter No Filter Green Filter LED Light and Analog Meters Selenium photocell not suited to measuring illuminance under LED sources If it doesn t use a battery and an analog gage, it may have issues Low Cost Digital Meters Diffuser (Cosine Corrector) Photosensor (under diffuser) Gage (Voltmeter w/firmware) Amprobe LM-200LED Calibration using varistor and firmware calibrated for all light sources and daylight Detachable sensor head is an excellent feature Hundreds of similar meters from $50 to $1200 7

CM-2 Photographers light meters -with spot attachment Meter LED Error Vs.

8 Quality Digital Meters Detachable sensor head Array of multiple sensors Minolta TM-10 Other Useful Meters Many older digital light Meters from fluorescent era forward Check against a known modern meter to verify Minolta T-1H Minolta AM-4F Minolta CM-2 Photographers light meters -with spot attachment Meter LED Error Vs. Vs. Vs. Illuminance K 3000K 3500K 4000K 5000K DW LM-200LED Minolta T-1H GE

Meter LED Error Vs. Vs. Lo Light 100 90 80 70 60 50 40 30 20 10 0 2700 3000 3500 4000 5000 K K K K K LM-200LED Lo 74 82 83 87 90 GE217 Lo 51 51.5 51.

250 240 245 240 Illuminance Old School Modular Scientific Meters Tektronix Multiple detachable detectors Electronics- readout per attached head Various remote and attached sensors Calibration using

9 Meter LED Error Vs. Vs. Lo Light K K K K K LM-200LED Lo GE217 Lo GE 214 Lo Illuminance Hi Light K K K K K LM-200 Hi GE217 Hi GE214 Hi Illuminance Old School Modular Scientific Meters Tektronix Multiple detachable detectors Electronics- readout per attached head Various remote and attached sensors Calibration using firmware and varistor at gage with filters depending in attachment Modern Spectral Light Meter App Base Diffuser (Cosine Corrector) Multiple spectral sensor Software driven gage and readout Calibration using software Assensetek Lighting Passport Detachable sensor head 9

Modern Meter Delivered Results 90 Parameters CCT CRI(Ra)(R1-R8) Re(R1-15) R1~R15 CQS Illuminance Foot

377-2008 IEC-SDCM TM-30-15(Rf, Rg & Diagram) Peak Wavelength (λp) Dominant Wavelength (λd) Purity Duv SP

Relative Humidity Modern Meter Computer Interface Desktop software evaluation tools CCT CRI(Ra)(R1-R8)

10 Modern Meter Delivered Results 90 Parameters CCT CRI(Ra)(R1-R8) Re(R1-15) R1~R15 CQS Illuminance Foot Candle CIE 1931 CIE 1976 Spectrum Diagram C IEC-SDCM TM-30-15(Rf, Rg & Diagram) Peak Wavelength (λp) Dominant Wavelength (λd) Purity Duv SP Ratio PPFD (380~780 nm) Flicker Frequency(5-200 Hz) Flicker Percentage Flicker Index Temperature Relative Humidity Modern Meter Computer Interface Desktop software evaluation tools CCT CRI(Ra)(R1-R8) Re(R1-15) R1~R15 CQS Illuminance Foot Candle CIE 1931 CIE 1976 Spectrum Diagram C IEC-SDCM TM-30-15(Rf, Rg & Diagram) Peak Wavelength (λp) Dominant Wavelength (λd) Purity Duv SP Ratio PPFD (380~780 nm) Flicker Frequency(5-200 Hz) Flicker Percentage Flicker Index Temperature Relative Humidity Integrated Meters UPRTek Metrue Sim-2 Minolta CL70 Gigahertz Optic Minolta CL500 10

Lab Meters PC Connected Mightex CCD Spectrometer Ocean Optics Jaz For fixed

>$2,000 Illuminance + 89 other Parameters All readings within +/- 0.

11 Lab Meters PC Connected Mightex CCD Spectrometer Ocean Optics Jaz For fixed installations Meters Reviewed See review and summary of 9 meters at: Lumeniquessl.com Modern Meter Accuracy Comparison <$100 Illuminance Only Vs. >$2,000 Illuminance + 89 other Parameters All readings within +/- 0.98% Illuminance Meter Comparison 2700K 3000K 3500K 4000K 5000K LED CCT >$2000 <$100 Meters do not need to be expensive to be precise and accurate 11

12 Meter Accuracy Comparison Vs. Vs. Vs. Vs. Assensetek LM-200LED Minolta T1H GE 214 GE 217 Incand Error Base 1.4% 0.5% 20.8% 39.9% Assensetek LM-200LED Minolta T1H GE 214 GE LED Error Base 1.2% 0.5% 25.2% 45.1% Analog meters disagree by >24% to one another Color Meter Error Vs. Vs. Older photographic color meters are not calibrated to accurately read LED CCT 0 Color Deviation from Published LED CCT Assensetek Minolta CM2 Low Mightex Minolta CM2 High When and Why a New Meter All analog meters should be discarded Replace color meters not designed to include LEDs specifically in specifications Repair and or replace meters out of calibration Replace old cheap meters after 5 years +/- Have quality meters calibrated every 1-3 years depending on use New meters deliver valuable data Color Flicker Calculated factors, software connection, data output, etc. Separation of sensor head from instrument When a meter produces results that are inconsistent or suspicious Reading to reading should be within 1-5% of new reference 12

Beyond the basic function of illuminance on a desktop Photometric Meters reading Fc or Lux can be used to generate candela data for comparisons and evaluation 12Fc x 25² = 7,500cd 129.17Lux x 7.

13 Beyond the basic function of illuminance on a desktop Photometric Meters reading Fc or Lux can be used to generate candela data for comparisons and evaluation 12Fc x 25² = 7,500cd Lux x 7.62² = 7,500cd 55 Distance D (25 or 7.62M) 12Fc Lux Candela = Fc x D² (in feet) Lux = Fc x D² (in meters) Align meter normal to incident angle Transmission Transmission = FC or Lux through material / FC or Lux no material Align material normal to incident angle and close to meter sensor Fc through material = 112Fc Fc without material = 238Fc 112/238 = 47% Transmission Align meter normal to incident angle 13

Reflectance Reflectivity = FC or Lux off material (A) / FC or Lux direct (B) Distance A+C

112Fc Fc direct = 238Fc 112/238 = 47% Reflectance Align meter normal to incident angle

Rotate in X axis in any degree steps desired with controller or manual crank Can be also be

14 Reflectance Reflectivity = FC or Lux off material (A) / FC or Lux direct (B) Distance A+C and B+C must be identical A C Incident and reflected angles should match B Fc off material = 112Fc Fc direct = 238Fc 112/238 = 47% Reflectance Align meter normal to incident angle Simple Benchtop Goniometer Mount for small fixtures/lamps Mount any illuminance meter here Rotate in X axis in any degree steps desired with controller or manual crank Can be also be done with two tripods, protractor and string Larger Simple Lab Setup Benchtop Goniometer on steroids 14

Special Lab Setups Exposure and transmission evaluation Small source tabletop goniometer Special purposes and comparison test rigs Relative

optics must be equivelant Comparison of a known reference source to another 24 24 A: Known good source Ref: 600lm Reads 30Fc B: Comparison

?? Reads 36Fc 600/30 = 20 (Ratio of lumens per Fc measured) 20 x 36 = 720lm (Source B relative lumens) Applying Relative Measurement Light meter

15 Special Lab Setups Exposure and transmission evaluation Small source tabletop goniometer Special purposes and comparison test rigs Relative Measurement Comparisons and ratios do not require absolute values Precision (repeatability) more important than accuracy Distance to subject and optics must be equivelant Comparison of a known reference source to another A: Known good source Ref: 600lm Reads 30Fc B: Comparison source Lumens??? Reads 36Fc 600/30 = 20 (Ratio of lumens per Fc measured) 20 x 36 = 720lm (Source B relative lumens) Applying Relative Measurement Light meter modified for use with sphere sensor Ref and Test sources must be of similar optical character Test Lumens Reading Multiplier Ref Reading Multiplier Lumens Test Test Metric values are less important than ratios to reference source 15

Relative Spot Measurement Brightness ratio using a spot meter C E B D ID Ev Comp Ratio F A A 10.1 A:C 1.4:1 B 5.7 A:B 1.9:1 C 7.2 E:C 1.7:1 D 8.1 A:D 1.2:1 G E 11.9 E:A 1.2:1 F 9.1 A:F 1.1:1 G 8.

16 Relative Spot Measurement Brightness ratio using a spot meter C E B D ID Ev Comp Ratio F A A 10.1 A:C 1.4:1 B 5.7 A:B 1.9:1 C 7.2 E:C 1.7:1 D 8.1 A:D 1.2:1 G E 11.9 E:A 1.2:1 F 9.1 A:F 1.1:1 G 8.0 A:G 1.3:1 Metric values are less important than ratios between target surfaces Common Measurement Errors Incorrect assumptions about what meters can do Lack of care in setting up meter to capture measurement Inconsistent measurement location Inconsistent distance from source Lack of preparation for repeating measurements Interference from surrounding sources or reflective surfaces Mismatch between meter and light source Observer interference White shirt effect on illuminance Red shirt effect on color measurement Wrong meter setting Poor equipment condition and lack of calibration Field Measurement for Repeatability Make a map of the space and note of conditions Establish a fixed x,y,z point that can be recaptured later Use a meter sensor mount vs. hand holding Tripod or monopod mount ideal Measure at night for artificial sources Measure without and without artificial light when measuring daylight contribution Capture artificial at night to differentiate contributions clearly Make field holding tools and keep them handy 16

Field Measurement for Repeatability Accuracy here is critical in monitoring lumen depreciation over time A few additional things to have in the tool bag Handy

17 Field Measurement for Repeatability Accuracy here is critical in monitoring lumen depreciation over time A few additional things to have in the tool bag Handy Tools to Increase Accuracy & Precision Tripod Monopod Tape Measure Level and Protractor or App Pocket Pointer String, tacks, tape Gray Card Color Checker Plans 17

Handy Accessories for Test Setup Tripod Adapter for Sensor Heads Black foil to make Masks Integrating Isolation Tube Laser Pointer Hold sensor head to ¼ x 20 bipod or monopod stand Block light from

can be anything that has good data behind it For casual non-lab use, a good downlight with solid photometric file from a manufacturer can be used Mount it a set distance from the meter Check 0 Nadir

18 Handy Accessories for Test Setup Tripod Adapter for Sensor Heads Black foil to make Masks Integrating Isolation Tube Laser Pointer Hold sensor head to ¼ x 20 bipod or monopod stand Block light from surrounding when measuring single fixture output Isolate a single light source for relative measurement Help in aligning and locating sensor Reference Sources to Establish Baseline A reference source can be anything that has good data behind it For casual non-lab use, a good downlight with solid photometric file from a manufacturer can be used Mount it a set distance from the meter Check 0 Nadir Candela by reading Fc x D² The result should be within 10% If good, keep the light as a reference for future meter checks and comparisons Temperature Meter Critical with LEDs Amprobe TMD-10 2 channel <$100 Temperature Meter K type thermocouples Various contact types At least 2 channels Temperature has a great impact on light output Reed SD channel <$200 18

Simple Flicker Meter See description and review at: Lumeniquessl.com http://wp.

meter in use and review at: Lumeniquessl.com http://wp.

19 Simple Flicker Meter See description and review at: Lumeniquessl.com If you see flicker, it exists the actual metrics won t change that Electronic Flicker Meter See meter in use and review at: Lumeniquessl.com UPRTek 250N SVM Calculation Also CCT/Lux/CRI <$1000 Understand what the metrics are and why they are meaningful A concept for multi-dimensional description of white lighting qualities 19

20 The IP Model A standard delivering classification information with some depth Volume of water Pressure/direction/immersio n 1-8 classification (8 highest) Water Dust IP Size of particle Environmental (movement) 1-6 classification (6 highest) Impact Size of object Impact energy 1-9 classification (8 highest) LQC Lighting Qualities Classification Aggregate multi-dimensional quality classification 1-5 values 5 highest Uniformity CCT Variation / COA Duv MacAdams Variable Color Fidelity Saturation Effects Spectral Consistency (lowest R value) LQC Light Quality Human Factors S/P Ratio Flicker Uniformity Applied Metrics CCT Limits (variation from the stated value) Duv Deviation above or below the Plankian locus MacAdam steps from center point of stated CCT Plankian locus intersection Rating 1-5, based on combined results of values 1 delivers the least uniform performance 5 delivers optimal uniformity 20

21 Quality Applied Metrics Average CRIe or TM-30 Rf Lowest specific R value included in average TM-30 Rg value Rating 1-5, based on combined results of values 1 delivers the lowest color quality 5 delivers optimal color performance and rendering Human Factors Applied Metrics S/P Ratio Flicker rating (Frequency, % and Index combined) Rating 1-5, based on combined results of values 1 delivers the lowest visual performance 5 delivers optimal visual performance LQC Metrics Uniformity Classification Metric Duv MacAdam CCT Var 1 >250 >+/ <+/ <+/ <+/ <100 <+/ Quality Classification Metric Lowest Individual CRIe or TM30Rf TM30 Rg value 1 <69 35 n/a > Human Factors Metric Flicker Freq Flicker S/P Ratio % Flicker Index 1 <.89 <200Hz >30 > <200Hz <30 < >200Hz <15 < Hz <4 <.01 5 >1.81 >2000Hz n/a n/a 21

Applied LQC Rating Examples LQC-235 Factory space with medium color demand, high visual performance demands Places emphasis on economy and visual

task light for critical visual performance Simple Workbook More detail and download the workbook: Lumeniquessl.com http://wp.

22 Applied LQC Rating Examples LQC-235 Factory space with medium color demand, high visual performance demands Places emphasis on economy and visual performance LQC-33 Budget specification with no human factors consideration LQC-55 High color performance for retail/museum LQC-555 Inspection task light for critical visual performance Simple Workbook More detail and download the workbook: Lumeniquessl.com Color Viewer Used in Testing Cree LEDs All 90CRI 2700K 3000K 3500K 4000K 5000K Dimmable from 500Fc to 10Fc More detail: Lumeniquessl.com 22

23 Happy Metering! This concludes The American Institute of Architects Continuing Education Systems Course Kevin Willmorth Lumenique, LLC

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