Sources & Surfaces Sources & Surfaces Evaluating Spectral Distribution Interactions Using Roadway Signage IESNA Roadway Lighting Committee April 2003 David M. Keith, FIES & Jefferey F. Knox
Sources & SurfacesSources & SurfacesEvaluating Spectral Distribution
InteractionsUsing Roadway Signage
IESNA Roadway Lighting CommitteeApril 2003
David M. Keith, FIES& Jefferey F. Knox
Sources & Surfaces: OverviewSources & Surfaces: Overview
Our world is not all shades of gray, but . . . “Lumen” is spectrally ignorant by
definition Therefore, since we use color to
communicate especially important information such as
should we evaluate visibility using full
spectral information that describes color?
Sources & Surfaces: Sources & Surfaces: BackgroundBackground
Luminous reflectance: Any of the geometric aspects of reflectance
in which both the incident and the reflected flux are weighted by the spectral luminous efficiency of radiant flux V(λ).
Note: Unless otherwise qualified, the term “reflectance” means luminous reflectance.
Sources: “GLOSSARY OF LIGHTING TERMINOLOGY” IESNA Lighting Handbook, 9th edition & IENSA RP-16-1996
Sources & Surfaces: Sources & Surfaces: BackgroundBackground
Reflectance = Lumensoff Lumenson
This means that “reflectance” is specific to each source’s spectral power distribution’s interaction with the surface’s spectral reflectance distribution
Contrast is calculated using reflectance
Sources & Surfaces: Sources & Surfaces: BackgroundBackground
Reflectance for surfaces is typically reported with no mention of the source being used in the evaluation, e.g. Figure 1-36, IESNA Lighting
Handbook, 9th edition ANSI/IESNA RP-8-00 luminance
calculation procedures (Annex A & IESNA Handbook, Figure 22-1)
Sources & Surfaces: Sources & Surfaces: BackgroundBackground
Reflectance for many (most?) exterior surfaces is only marginally dependent on source SPD, because most natural surfaces are approximately “gray”
Colored surfaces may be dependent on SPD interactions - how to find out?
Roadway signage is familiar, available & important example for such investigation
Sources & Surfaces: Sources & Surfaces: ProcedureProcedure
Collect spectral data for exterior light sources and signage surfaces
Combine using spectrally informed procedures to establish reflectances
Combine into appropriate pairs for calculating contrast values
Repeat with CIE LAB procedures for color difference evaluations
Sources Used in this WorkSources Used in this WorkEqual Energy
constant radiation across the entire spectrumD65
a ‘daylight’ source of 6500 K from CIEIlluminant A
an incandescent source of 2850 K from CIEHPS
SPDs of four High Pressure Sodium wattagesMH
SPDs for Metal Halide Sources250 or 400 watt, universal or horizontal
Fluorescentsfour different CCT’s: 30, 35, 41 & 65
Sources Used in this WorkSources Used in this WorkSource Abbr. x y CCT CRI Equal Energy EqE 0.33 0.33 5455 95*CIE D65 C_D 0.31 0.33 6502 100CIE Illuminant A C_A 0.45 0.41 2856 100HPS 100W H10 0.52 0.42 2060 16HPS 150W H15 0.51 0.42 2174 21HPS 250W H25 0.52 0.41 2001 21HPS 400W H40 0.52 0.42 2116 16MH 250W Horiz M2h 0.39 0.40 4002 64*MH 250W Univ M2u 0.38 0.40 4061 53*MH 400W Horiz M4h 0.37 0.39 4319 68*MH 400W Univ M4u 0.40 0.40 3776 58*Fluorescent 3000K F30 0.44 0.41 2919 85Fluorescent 3500K F35 0.42 0.40 3326 87Fluorescent 4100K F41 0.39 0.38 3813 87Fluorescent 6500K F65 0.32 0.34 6088 87
Surfaces Used in this WorkSurfaces Used in this Work
Roadway signage films manufactured materials, not paints
Three different series from 3M Engineer Grade (ENG) High Intensity Flexible Workzone
Sheeting (HIS) Visual Impact Sheeting (VIS) a.k.a.
Scotch Lite Diamond Grade
Surfaces Used in this WorkSurfaces Used in this Work
each series has multiple colors white yellow red green blue
two series (HIS & EG) also have brown orange
Surfaces Used in this WorkSurfaces Used in this WorkAll meet FHWA Specifications CIE D65 CIE Illuminant A
x y x yWhite ENG 0.32 0.34 0.45 0.41
HIS 0.31 0.33 0.44 0.41VIP 0.31 0.33 0.44 0.41
Blue ENG 0.14 0.11 0.16 0.18HIS 0.14 0.13 0.15 0.22VIP 0.15 0.13 0.16 0.24
Green ENG 0.14 0.42 0.18 0.51HIS 0.14 0.44 0.17 0.53VIP 0.13 0.42 0.17 0.51
Yellow ENG 0.50 0.48 0.55 0.44HIS 0.52 0.47 0.57 0.43VIP 0.53 0.47 0.57 0.43
Orange ENG 0.58 0.40 0.61 0.39HIS 0.54 0.40 0.60 0.39
Red ENG 0.66 0.33 0.68 0.32HIS 0.66 0.32 0.68 0.32VIP 0.66 0.32 0.68 0.32
Brown ENG 0.52 0.40 0.59 0.39HIS 0.50 0.40 0.58 0.39
Procedure: ReflectanceProcedure: Reflectance Lumens on Lumens on = K*[S()*v()]
Lumens off Lumens offtypical = ρaverage * {K*[S()*v()]}
Lumens offrevised = K * [ S() * v() * ρ () ]
ReflectancesReflectances EqE C_D C_A H10 H15 H25 H40 M2h M2u M4h M4u F30 F35
F41 F65
White ENG 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 HIS 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 VIP 41 42 41 41 41 41 41 41 41 41 41 41 41 41 42
Blue ENG 2.4 2.6 1.5 0.7 0.8 0.8 0.8 1.8 1.5 1.9 1.6 1.1 1.3 1.5 2.1 HIS 3.3 3.5 2.2 0.8 0.9 0.8 0.9 2.4 2.2 2.6 2.2 1.8 2.1 2.3 3.1 VIP 1.9 2.1 1.3 0.5 0.6 0.5 0.6 1.5 1.4 1.6 1.3 1.2 1.4 1.5 1.9
Green ENG 5.5 5.9 4.1 1.6 1.7 1.6 1.6 4.4 4.0 4.7 4.0 3.8 4.1 4.5 5.5 HIS 6.2 6.6 4.6 1.5 1.7 1.6 1.6 4.9 4.4 5.2 4.4 4.5 4.9 5.3 6.5 VIP 5.6 6.0 4.2 1.6 1.7 1.6 1.6 4.5 4.0 4.8 4.0 3.8 4.2 4.5 5.6
Yellow ENG 37 35 41 48 48 48 48 40 42 40 41 42 41 40 37 HIS 18 17 21 25 25 25 25 20 21 20 21 21 20 20 18 VIP 26 25 30 37 37 37 37 30 31 29 31 30 29 28 26
Orange ENG 25 23 31 44 43 44 44 30 31 29 31 28 26 25 20 HIS 17 16 20 26 25 26 26 19 19 18 20 20 19 18 16
Red ENG 6.1 5.4 8.5 7.8 7.4 8.3 7.5 5.1 4.5 5.0 5.1 8.4 7.7 7.1 5.5 HIS 4.2 3.7 5.8 5.7 5.4 6.1 5.5 3.7 3.3 3.6 3.7 5.7 5.3 4.8 3.7 VIP 6.7 5.9 9.5 8.8 8.4 9.5 8.5 5.5 4.8 5.4 5.5 9.8 9.0 8.3 6.3
Brown ENG 5.8 5.5 6.9 7.5 7.3 7.6 7.4 6.0 5.9 5.9 6.1 7.2 6.9 6.6 5.9 HIS 4.5 4.3 5.3 6.3 6.1 6.3 6.2 4.9 5.0 4.8 5.0 5.0 4.8 4.7 4.2
ReflectancesReflectances EqE C_D C_A H10 H15 H25 H40 M2h M2u M4h M4u F30 F35
F41 F65
White ENG 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 HIS 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 VIP 41 42 41 41 41 41 41 41 41 41 41 41 41 41 42
Blue ENG 2.4 2.6 1.5 0.7 0.8 0.8 0.8 1.8 1.5 1.9 1.6 1.1 1.3 1.5 2.1 HIS 3.3 3.5 2.2 0.8 0.9 0.8 0.9 2.4 2.2 2.6 2.2 1.8 2.1 2.3 3.1 VIP 1.9 2.1 1.3 0.5 0.6 0.5 0.6 1.5 1.4 1.6 1.3 1.2 1.4 1.5 1.9
Green ENG 5.5 5.9 4.1 1.6 1.7 1.6 1.6 4.4 4.0 4.7 4.0 3.8 4.1 4.5 5.5 HIS 6.2 6.6 4.6 1.5 1.7 1.6 1.6 4.9 4.4 5.2 4.4 4.5 4.9 5.3 6.5 VIP 5.6 6.0 4.2 1.6 1.7 1.6 1.6 4.5 4.0 4.8 4.0 3.8 4.2 4.5 5.6
Yellow ENG 37 35 41 48 48 48 48 40 42 40 41 42 41 40 37 HIS 18 17 21 25 25 25 25 20 21 20 21 21 20 20 18 VIP 26 25 30 37 37 37 37 30 31 29 31 30 29 28 26
Orange ENG 25 23 31 44 43 44 44 30 31 29 31 28 26 25 20 HIS 17 16 20 26 25 26 26 19 19 18 20 20 19 18 16
Red ENG 6.1 5.4 8.5 7.8 7.4 8.3 7.5 5.1 4.5 5.0 5.1 8.4 7.7 7.1 5.5 HIS 4.2 3.7 5.8 5.7 5.4 6.1 5.5 3.7 3.3 3.6 3.7 5.7 5.3 4.8 3.7 VIP 6.7 5.9 9.5 8.8 8.4 9.5 8.5 5.5 4.8 5.4 5.5 9.8 9.0 8.3 6.3
Brown ENG 5.8 5.5 6.9 7.5 7.3 7.6 7.4 6.0 5.9 5.9 6.1 7.2 6.9 6.6 5.9 HIS 4.5 4.3 5.3 6.3 6.1 6.3 6.2 4.9 5.0 4.8 5.0 5.0 4.8 4.7 4.2
ReflectancesReflectances EqE C_D C_A H10 H15 H25 H40 M2h M2u M4h M4u F30 F35
F41 F65
White ENG 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 HIS 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 VIP 41 42 41 41 41 41 41 41 41 41 41 41 41 41 42
Blue ENG 2.4 2.6 1.5 0.7 0.8 0.8 0.8 1.8 1.5 1.9 1.6 1.1 1.3 1.5 2.1 HIS 3.3 3.5 2.2 0.8 0.9 0.8 0.9 2.4 2.2 2.6 2.2 1.8 2.1 2.3 3.1 VIP 1.9 2.1 1.3 0.5 0.6 0.5 0.6 1.5 1.4 1.6 1.3 1.2 1.4 1.5 1.9
Green ENG 5.5 5.9 4.1 1.6 1.7 1.6 1.6 4.4 4.0 4.7 4.0 3.8 4.1 4.5 5.5 HIS 6.2 6.6 4.6 1.5 1.7 1.6 1.6 4.9 4.4 5.2 4.4 4.5 4.9 5.3 6.5 VIP 5.6 6.0 4.2 1.6 1.7 1.6 1.6 4.5 4.0 4.8 4.0 3.8 4.2 4.5 5.6
Yellow ENG 37 35 41 48 48 48 48 40 42 40 41 42 41 40 37 HIS 18 17 21 25 25 25 25 20 21 20 21 21 20 20 18 VIP 26 25 30 37 37 37 37 30 31 29 31 30 29 28 26
Orange ENG 25 23 31 44 43 44 44 30 31 29 31 28 26 25 20 HIS 17 16 20 26 25 26 26 19 19 18 20 20 19 18 16
Red ENG 6.1 5.4 8.5 7.8 7.4 8.3 7.5 5.1 4.5 5.0 5.1 8.4 7.7 7.1 5.5 HIS 4.2 3.7 5.8 5.7 5.4 6.1 5.5 3.7 3.3 3.6 3.7 5.7 5.3 4.8 3.7 VIP 6.7 5.9 9.5 8.8 8.4 9.5 8.5 5.5 4.8 5.4 5.5 9.8 9.0 8.3 6.3
Brown ENG 5.8 5.5 6.9 7.5 7.3 7.6 7.4 6.0 5.9 5.9 6.1 7.2 6.9 6.6 5.9 HIS 4.5 4.3 5.3 6.3 6.1 6.3 6.2 4.9 5.0 4.8 5.0 5.0 4.8 4.7 4.2
Reflectances: HPS vs MHReflectances: HPS vs MH High Pressure Sodium Metal HalideAvg StDev Avg StDev HPS/MH
White ENG 45 0.0 45 0.0 1.0 HIS 33 0.0 33 0.0 1.0 VIP 41 0.1 41 0.0 1.0
Blue ENG 0.8 0.1 1.7 0.2 0.5 HIS 0.8 0.1 2.4 0.2 0.4 VIP 0.5 0.1 1.5 0.1 0.4
Green ENG 1.6 0.0 4.3 0.3 0.4 HIS 1.6 0.1 4.7 0.4 0.3 VIP 1.6 0.0 4.3 0.4 0.4
Yellow ENG 48 0.1 41 1.0 1.2 HIS 25 0.2 20 0.5 1.2 VIP 37 0.2 30 0.8 1.2
Orange ENG 44 0.7 30 1.0 1.5 HIS 26 0.4 19 0.5 1.4
Red ENG 7.8 0.4 4.9 0.3 1.6 HIS 5.7 0.3 3.6 0.2 1.6 VIP 8.8 0.5 5.3 0.3 1.7
Brown ENG 7.5 0.1 6.0 0.1 1.2 HIS 6.2 0.1 4.9 0.1 1.3
Procedure: ContrastProcedure: Contrast
C = (Lmax - Lmin ) / (Lmax) Cmod = (Lmax - Lmin ) / (Lmax + Lmin)
For a perfectly diffuse reflector (or surfaces with similar reflectance geometric properties)Luminance = Exitance Exitance = Lumenson * Reflectance
C = (ρ max - ρ min ) / (ρ max)Cmod = (ρ max - ρ min ) / (ρ max + ρ min)
Still calculated in lumens (more accurately determined)
Procedure: ContrastsProcedure: Contrasts Color pairs determined by common sign
combinations white - red (Stop, Yield, One-way) black - orange (work/construction, detour) black - yellow (caution, warning, advisory) white - green (information, direction, exit)
Combinations evaluated using sign films in the same series e.g. ENG red & ENG white, HIS red & HIS white, VIP red & VIP white
Procedure: Color Procedure: Color DifferenceDifference Color Difference Threshold
The difference in chromaticity or luminance between two colors that makes them just perceptibly different. The difference may be in hue, saturation, brightness (lightness for surface colors) or a combination of the three.
This model more accurately reflects foveal vision which does not see in black & white - for example observe the horizontal line above - as it shades from black to white, it remains visible against the colored background (or does it?)
Procedure: CIE L*a*b*Procedure: CIE L*a*b* First, the illuminant in the local context can be
specified, also in terms of the R, G and B cone outputs, as a reference white. The model treats all colors as a combination of surface color and illuminant color, which allows the model to be applied across a wider range of viewing conditions.
Second, the trichromatic XYZ "primaries" are transformed mathematically to represent the Y/B and R/G opponent dimensions (along with a lightness or white/black dimension), which allows the models to reproduce the basic structure of color experience.
Procedure: CIE L*a*b*Procedure: CIE L*a*b* Finally, CIELAB is based on a set of imaginary
“primary” lights that have been chosen specifically to make the color space perceptually uniform (at least, to the degree possible in a three dimensional model). That is, a difference of 10 units on the lightness dimension has the same perceptual impact as a 10 unit difference on the Y/B or R/G dimensions -- either separately or in combination.
delLAB (ΔLAB) is the Euclidean distance between two color loci in the CIE L*a*b* space
ΔLAB = {(ΔL)2 + (Δa)2 + (Δb)2}1/2
C & delLAB: C & delLAB: white white -- redred ENG Series HIS Series VIP Series
Source C Cmod dLAB C Cmod dLAB C Cmod dLAB
EqE 0.86 0.76 82 0.87 0.77 64 0.84 0.72 87C_D 0.88 0.78 82 0.80 0.80 74 0.86 0.75 87C_A 0.81 0.68 85 0.82 0.70 77 0.77 0.62 92
H10 0.83 0.70 68 0.83 0.70 63 0.78 0.64 74H15 0.83 0.72 69 0.83 0.72 64 0.79 0.66 75H25 0.81 0.69 70 0.81 0.69 64 0.77 0.62 76H40 0.83 0.71 68 0.83 0.71 63 0.79 0.66 74
M2h 0.89 0.80 74 0.89 0.80 65 0.87 0.76 78M2u 0.90 0.82 70 0.90 0.82 63 0.88 0.79 73M4h 0.89 0.80 74 0.89 0.80 67 0.87 0.77 78M4u 0.89 0.80 71 0.89 0.80 64 0.87 0.76 74
F30 0.81 0.68 81 0.83 0.70 73 0.76 0.62 89F35 0.83 0.71 81 0.84 0.72 74 0.78 0.64 89F41 0.84 0.73 81 0.85 0.75 74 0.80 0.67 89F65 0.88 0.78 81 0.89 0.80 73 0.85 0.74 86
C & delLAB: C & delLAB: white white -- redred ENG Series HIS Series VIP Series
Source C Cmod dLAB C Cmod dLAB C Cmod dLAB
EqE 0.86 0.76 82 0.87 0.77 64 0.84 0.72 87C_D 0.88 0.78 82 0.80 0.80 74 0.86 0.75 87C_A 0.81 0.68 85 0.82 0.70 77 0.77 0.62 92
H10 0.83 0.70 68 0.83 0.70 63 0.78 0.64 74H15 0.83 0.72 69 0.83 0.72 64 0.79 0.66 75H25 0.81 0.69 70 0.81 0.69 64 0.77 0.62 76H40 0.83 0.71 68 0.83 0.71 63 0.79 0.66 74
M2h 0.89 0.80 74 0.89 0.80 65 0.87 0.76 78M2u 0.90 0.82 70 0.90 0.82 63 0.88 0.79 73M4h 0.89 0.80 74 0.89 0.80 67 0.87 0.77 78M4u 0.89 0.80 71 0.89 0.80 64 0.87 0.76 74
F30 0.81 0.68 81 0.83 0.70 73 0.76 0.62 89F35 0.83 0.71 81 0.84 0.72 74 0.78 0.64 89F41 0.84 0.73 81 0.85 0.75 74 0.80 0.67 89F65 0.88 0.78 81 0.89 0.80 73 0.85 0.74 86
C & delLAB: C & delLAB: white white -- redred ENG Series HIS Series VIP Series
Source C Cmod dLAB C Cmod dLAB C Cmod dLAB
EqE 0.86 0.76 82 0.87 0.77 64 0.84 0.72 87C_D 0.88 0.78 82 0.80 0.80 74 0.86 0.75 87C_A 0.81 0.68 85 0.82 0.70 77 0.77 0.62 92
H10 0.83 0.70 68 0.83 0.70 63 0.78 0.64 74H15 0.83 0.72 69 0.83 0.72 64 0.79 0.66 75H25 0.81 0.69 70 0.81 0.69 64 0.77 0.62 76H40 0.83 0.71 68 0.83 0.71 63 0.79 0.66 74
M2h 0.89 0.80 74 0.89 0.80 65 0.87 0.76 78M2u 0.90 0.82 70 0.90 0.82 63 0.88 0.79 73M4h 0.89 0.80 74 0.89 0.80 67 0.87 0.77 78M4u 0.89 0.80 71 0.89 0.80 64 0.87 0.76 74
F30 0.81 0.68 81 0.83 0.70 73 0.76 0.62 89F35 0.83 0.71 81 0.84 0.72 74 0.78 0.64 89F41 0.84 0.73 81 0.85 0.75 74 0.80 0.67 89F65 0.88 0.78 81 0.89 0.80 73 0.85 0.74 86
C & delLAB: C & delLAB: blackblack -- orangeorange
ENG Series HIS Series Source C Cmod dLAB C Cmod dLAB
EqE 0.92 0.85 102 0.88 0.79 73C_D 0.91 0.84 101 0.88 0.78 71C_A 0.94 0.88 112 0.90 0.82 81
H10 0.95 0.91 120 0.92 0.86 85H15 0.95 0.91 118 0.92 0.85 83H25 0.95 0.91 119 0.92 0.86 85H40 0.95 0.91 119 0.92 0.86 85
M2h 0.93 0.87 108 0.89 0.81 75M2u 0.93 0.88 107 0.90 0.82 72M4h 0.93 0.87 107 0.89 0.80 74M4u 0.94 0.88 108 0.90 0.81 75
F30 0.93 0.87 110 0.90 0.82 80F35 0.92 0.86 109 0.90 0.81 78F41 0.92 0.85 106 0.89 0.80 78F65 0.90 0.82 100 0.87 0.77 72
C & delLAB: C & delLAB: blackblack -- orangeorange
ENG Series HIS Series Source C Cmod dLAB C Cmod dLAB
EqE 0.92 0.85 102 0.88 0.79 73C_D 0.91 0.84 101 0.88 0.78 71C_A 0.94 0.88 112 0.90 0.82 81
H10 0.95 0.91 120 0.92 0.86 85H15 0.95 0.91 118 0.92 0.85 83H25 0.95 0.91 119 0.92 0.86 85H40 0.95 0.91 119 0.92 0.86 85
M2h 0.93 0.87 108 0.89 0.81 75M2u 0.93 0.88 107 0.90 0.82 72M4h 0.93 0.87 107 0.89 0.80 74M4u 0.94 0.88 108 0.90 0.81 75
F30 0.93 0.87 110 0.90 0.82 80F35 0.92 0.86 109 0.90 0.81 78F41 0.92 0.85 106 0.89 0.80 78F65 0.90 0.82 100 0.87 0.77 72
C & delLAB: C & delLAB: blackblack -- orangeorange
ENG Series HIS Series Source C Cmod dLAB C Cmod dLAB
EqE 0.92 0.85 102 0.88 0.79 73C_D 0.91 0.84 101 0.88 0.78 71C_A 0.94 0.88 112 0.90 0.82 81
H10 0.95 0.91 120 0.92 0.86 85H15 0.95 0.91 118 0.92 0.85 83H25 0.95 0.91 119 0.92 0.86 85H40 0.95 0.91 119 0.92 0.86 85
M2h 0.93 0.87 108 0.89 0.81 75M2u 0.93 0.88 107 0.90 0.82 72M4h 0.93 0.87 107 0.89 0.80 74M4u 0.94 0.88 108 0.90 0.81 75
F30 0.93 0.87 110 0.90 0.82 80F35 0.92 0.86 109 0.90 0.81 78F41 0.92 0.85 106 0.89 0.80 78F65 0.90 0.82 100 0.87 0.77 72
C & delLAB: C & delLAB: blackblack -- yellowyellow ENG Series HIS Series VIP Series
Source C Cmod dLAB C Cmod dLAB C Cmod dLAB
EqE 0.95 0.90 111 0.89 0.80 91 0.92 0.86 106C_D 0.94 0.89 108 0.89 0.79 89 0.92 0.85 105C_A 0.95 0.91 112 0.90 0.82 94 0.93 0.88 110
H10 0.96 0.92 121 0.92 0.85 101 0.95 0.90 117H15 0.96 0.92 120 0.92 0.85 100 0.95 0.90 116H25 0.96 0.92 121 0.92 0.85 101 0.95 0.90 118H40 0.96 0.92 121 0.92 0.85 101 0.95 0.90 118
M2h 0.95 0.91 114 0.90 0.82 94 0.93 0.87 110M2u 0.95 0.91 117 0.90 0.82 95 0.93 0.88 111M4h 0.95 0.90 113 0.90 0.82 94 0.93 0.87 109M4u 0.95 0.91 116 0.90 0.82 96 0.93 0.88 111
F30 0.95 0.91 114 0.91 0.83 95 0.93 0.88 109F35 0.95 0.91 114 0.90 0.82 95 0.93 0.87 110F41 0.95 0.91 114 0.90 0.82 94 0.93 0.87 108 F65 0.95 0.90 111 0.89 0.80 90 0.92 0.86 104
C & delLAB: C & delLAB: blackblack -- yellowyellow ENG Series HIS Series VIP Series
Source C Cmod dLAB C Cmod dLAB C Cmod dLAB
EqE 0.95 0.90 111 0.89 0.80 91 0.92 0.86 106C_D 0.94 0.89 108 0.89 0.79 89 0.92 0.85 105C_A 0.95 0.91 112 0.90 0.82 94 0.93 0.88 110
H10 0.96 0.92 121 0.92 0.85 101 0.95 0.90 117H15 0.96 0.92 120 0.92 0.85 100 0.95 0.90 116H25 0.96 0.92 121 0.92 0.85 101 0.95 0.90 118H40 0.96 0.92 121 0.92 0.85 101 0.95 0.90 118
M2h 0.95 0.91 114 0.90 0.82 94 0.93 0.87 110M2u 0.95 0.91 117 0.90 0.82 95 0.93 0.88 111M4h 0.95 0.90 113 0.90 0.82 94 0.93 0.87 109M4u 0.95 0.91 116 0.90 0.82 96 0.93 0.88 111
F30 0.95 0.91 114 0.91 0.83 95 0.93 0.88 109F35 0.95 0.91 114 0.90 0.82 95 0.93 0.87 110F41 0.95 0.91 114 0.90 0.82 94 0.93 0.87 108 F65 0.95 0.90 111 0.89 0.80 90 0.92 0.86 104
C & delLAB: C & delLAB: blackblack -- yellowyellow ENG Series HIS Series VIP Series
Source C Cmod dLAB C Cmod dLAB C Cmod dLAB
EqE 0.95 0.90 111 0.89 0.80 91 0.92 0.86 106C_D 0.94 0.89 108 0.89 0.79 89 0.92 0.85 105C_A 0.95 0.91 112 0.90 0.82 94 0.93 0.88 110
H10 0.96 0.92 121 0.92 0.85 101 0.95 0.90 117H15 0.96 0.92 120 0.92 0.85 100 0.95 0.90 116H25 0.96 0.92 121 0.92 0.85 101 0.95 0.90 118H40 0.96 0.92 121 0.92 0.85 101 0.95 0.90 118
M2h 0.95 0.91 114 0.90 0.82 94 0.93 0.87 110M2u 0.95 0.91 117 0.90 0.82 95 0.93 0.88 111M4h 0.95 0.90 113 0.90 0.82 94 0.93 0.87 109M4u 0.95 0.91 116 0.90 0.82 96 0.93 0.88 111
F30 0.95 0.91 114 0.91 0.83 95 0.93 0.88 109F35 0.95 0.91 114 0.90 0.82 95 0.93 0.87 110F41 0.95 0.91 114 0.90 0.82 94 0.93 0.87 108 F65 0.95 0.90 111 0.89 0.80 90 0.92 0.86 104
C & delLAB: C & delLAB: white white -- greengreen ENG Series HIS Series VIP Series
Source C Cmod dLAB C Cmod dLAB C Cmod dLAB
EqE 0.88 0.78 72 0.81 0.68 71 0.87 0.76 72C_D 0.87 0.77 71 0.80 0.67 69 0.86 0.75 72C_A 0.91 0.83 74 0.86 0.75 71 0.90 0.81 73
H10 0.96 0.93 73 0.95 0.91 65 0.96 0.92 69H15 0.96 0.93 72 0.95 0.90 65 0.96 0.92 68H25 0.96 0.93 73 0.95 0.91 65 0.96 0.92 68H40 0.96 0.93 73 0.95 0.91 65 0.96 0.92 69
M2h 0.90 0.82 71 0.85 0.74 68 0.89 0.80 69M2u 0.91 0.84 68 0.87 0.76 64 0.90 0.82 67M4h 0.90 0.81 71 0.84 0.73 69 0.88 0.79 70M4u 0.91 0.84 69 0.87 0.76 66 0.90 0.82 68
F30 0.91 0.84 68 0.86 0.76 65 0.91 0.83 66F35 0.91 0.83 67 0.85 0.74 65 0.90 0.81 66F41 0.90 0.82 68 0.84 0.72 65 0.89 0.80 67F65 0.88 0.78 67 0.80 0.67 65 0.87 0.76 69
C & delLAB: C & delLAB: white white -- greengreen ENG Series HIS Series VIP Series
Source C Cmod dLAB C Cmod dLAB C Cmod dLAB
EqE 0.88 0.78 72 0.81 0.68 71 0.87 0.76 72C_D 0.87 0.77 71 0.80 0.67 69 0.86 0.75 72C_A 0.91 0.83 74 0.86 0.75 71 0.90 0.81 73
H10 0.96 0.93 73 0.95 0.91 65 0.96 0.92 69H15 0.96 0.93 72 0.95 0.90 65 0.96 0.92 68H25 0.96 0.93 73 0.95 0.91 65 0.96 0.92 68H40 0.96 0.93 73 0.95 0.91 65 0.96 0.92 69
M2h 0.90 0.82 71 0.85 0.74 68 0.89 0.80 69M2u 0.91 0.84 68 0.87 0.76 64 0.90 0.82 67M4h 0.90 0.81 71 0.84 0.73 69 0.88 0.79 70M4u 0.91 0.84 69 0.87 0.76 66 0.90 0.82 68
F30 0.91 0.84 68 0.86 0.76 65 0.91 0.83 66F35 0.91 0.83 67 0.85 0.74 65 0.90 0.81 66F41 0.90 0.82 68 0.84 0.72 65 0.89 0.80 67F65 0.88 0.78 67 0.80 0.67 65 0.87 0.76 69
C & delLAB: C & delLAB: white white -- greengreen ENG Series HIS Series VIP Series
Source C Cmod dLAB C Cmod dLAB C Cmod dLAB
EqE 0.88 0.78 72 0.81 0.68 71 0.87 0.76 72C_D 0.87 0.77 71 0.80 0.67 69 0.86 0.75 72C_A 0.91 0.83 74 0.86 0.75 71 0.90 0.81 73
H10 0.96 0.93 73 0.95 0.91 65 0.96 0.92 69H15 0.96 0.93 72 0.95 0.90 65 0.96 0.92 68H25 0.96 0.93 73 0.95 0.91 65 0.96 0.92 68H40 0.96 0.93 73 0.95 0.91 65 0.96 0.92 69
M2h 0.90 0.82 71 0.85 0.74 68 0.89 0.80 69M2u 0.91 0.84 68 0.87 0.76 64 0.90 0.82 67M4h 0.90 0.81 71 0.84 0.73 69 0.88 0.79 70M4u 0.91 0.84 69 0.87 0.76 66 0.90 0.82 68
F30 0.91 0.84 68 0.86 0.76 65 0.91 0.83 66F35 0.91 0.83 67 0.85 0.74 65 0.90 0.81 66F41 0.90 0.82 68 0.84 0.72 65 0.89 0.80 67F65 0.88 0.78 67 0.80 0.67 65 0.87 0.76 69
““How to use these How to use these results”results” If signs are “iconic” - the image is what
matters, not the information within - then reflectance of the surface should be maximised contrast and delLAB values are not as important Stop signs’ highest reflectance from C_A and
HPS If signs are “informational” (read text) then
reflectance is not as important contrast and delLAB should be maximized work, caution and “direction/exit” colors have
highest values from HPS (nearly as high for C_A)
Future WorkFuture Work Investigate additional colors and
surfaces Incorporation of appropriate mesopic
spectral luminous efficiency function(s) for foveal vision
Application of a model for evaluating age effects
Further investigate appropriate color difference models (such as CIE LAB)
SummarySummary Keep the spectral information in the
calculation procedure Spectral effects of illuminants cannot
be evaluated without considering the spectral reflectance of the lighted surfaces
All this is evaluated as single bounce applications (no inter-reflections!)
Sources & SurfacesSources & SurfacesThis work was solely supported by
Luminous Design, Inc & Marshall Design, Incwho gratefully acknowledge the assistance of:
3M for data on signage reflectancePhilips Lighting for lamp SPD’s
email: [email protected]
Sources & SurfacesSources & SurfacesEvaluating Spectral Distribution
InteractionsUsing Roadway Signage
IESNA Roadway Lighting CommitteeApril 2003
David M. Keith, FIES& Jefferey F. Knox