Spectral atlas · v1

The Reactive Dye Library

Twenty-two industrial reactive dyes, each measured across thirty-five spectral bands at eight concentrations on a Datacolor 550 spectrophotometer. The colors you see are not stylized — they are computed straight from the instrument’s tristimulus values. The curves are the dyes’ literal fingerprints in light.

22
Dyes
176
Measurements
35
Spectral bands
360–700
Wavelength · nm

All dyes · sorted by hue angle

0° → 360°
2°20°29°31°34°43°52°54°63°68°79°205°233°262°267°269°275°277°279°280°285°358°

How to read a card

Each card opens with the dye’s masstone — the color at full strength. The thin band beneath it shows the same dye stepped down through every measured concentration. The chart plots reflectance (%) against wavelength (nm); the visible-spectrum strip underneath maps where in light each curve lives. The dashed marker is the dye’s peak absorption — the wavelength it eats most hungrily, and the source of its hue.

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Red · 2°
#A01B53

ROJO ASUFAST 7B

Beetroot freshly cut.

L*
35.6
a*
55.7
b*
1.4
C*
55.8
0255075100530 nm400500600700
Reflectance %Wavelength nm · 360–700

Beetroot freshly cut.

A church window in slanting light.

Crushed cochineal.

A red reactive dye with masstone L*35.6 a*55.7 b*1.4 (C*55.8, h°1). Peak absorption at 530 nm (2.3% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.999 — near-perfect linear build-up — predictable in recipe formulation. Concentration range 0.02%–4.00%, a 94× tinting strength span across the series.

Peak 530nmK/S 21.19Span 94×r 0.9998 samples · masstone 4.00%
Orange · 20°
#AC1D3B

ROJO BR ASUFAST BA 150%

Pomegranate split open.

L*
37.9
a*
56.9
b*
20.6
C*
60.5
0255075100530 nm400500600700
Reflectance %Wavelength nm · 360–700

Pomegranate split open.

A brick wall in late sun.

Dried chili stem.

A orange reactive dye with masstone L*37.9 a*56.9 b*20.6 (C*60.5, h°20). Peak absorption at 530 nm (2.4% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.983 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 58× tinting strength span across the series.

Peak 530nmK/S 19.72Span 57.6×r 0.9838 samples · masstone 4.00%
Orange · 29°
#B8202D

ESCARLATA ASUFAST F-2G

Sealing wax just pressed.

L*
40.3
a*
58.9
b*
32.6
C*
67.3
0255075100520 nm400500600700
Reflectance %Wavelength nm · 360–700

Sealing wax just pressed.

Lacquer on a Kyoto bowl.

The throat of a hibiscus.

A orange reactive dye with masstone L*40.3 a*58.9 b*32.7 (C*67.3, h°29). Peak absorption at 520 nm (2.1% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.989 — near-perfect linear build-up — predictable in recipe formulation. Concentration range 0.02%–4.00%, a 76× tinting strength span across the series.

Peak 520nmK/S 22.83Span 76.5×r 0.9908 samples · masstone 4.00%
Orange · 31°
#A12729

ESCARLATA ASUFAST BNL 200%

Dried hibiscus petals.

L*
36.4
a*
49.5
b*
29.5
C*
57.6
0255075100500 nm400500600700
Reflectance %Wavelength nm · 360–700

Dried hibiscus petals.

The flank of a fire engine.

Cinnabar on a temple wall.

A orange reactive dye with masstone L*36.3 a*49.5 b*29.5 (C*57.6, h°31). Peak absorption at 500 nm (2.1% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.982 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 64× tinting strength span across the series.

Peak 500nmK/S 23.26Span 64×r 0.9828 samples · masstone 4.00%
Orange · 34°
#492E29

PARDO ASUFAST PB

Wet bark after rain.

L*
21.9
a*
12.0
b*
8.1
C*
14.4
0255075100440 nm400500600700
Reflectance %Wavelength nm · 360–700

Wet bark after rain.

Old terracotta dust.

The inside of a fig before it splits.

A orange reactive dye with masstone L*21.9 a*12.0 b*8.1 (C*14.5, h°34). Peak absorption at 440 nm (2.3% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.983 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 52× tinting strength span across the series.

Peak 440nmK/S 21.01Span 52.2×r 0.9838 samples · masstone 4.00%
Orange · 43°
#5C3225

PARDO ASUFAST AGL

Toasted hazelnut skin.

L*
26.0
a*
17.6
b*
16.5
C*
24.2
0255075100440 nm400500600700
Reflectance %Wavelength nm · 360–700

Toasted hazelnut skin.

Sun-baked adobe.

A worn leather strap.

A orange reactive dye with masstone L*26.0 a*17.6 b*16.5 (C*24.2, h°43). Peak absorption at 440 nm (2.1% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.980 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 59× tinting strength span across the series.

Peak 440nmK/S 23.2Span 58.7×r 0.9808 samples · masstone 4.00%
Yellow · 52°
#CF5203

ANARANJADO ASUFAST 7GL

Persimmon at peak ripeness.

L*
51.0
a*
47.0
b*
60.0
C*
76.2
0255075100440 nm400500600700
Reflectance %Wavelength nm · 360–700

Persimmon at peak ripeness.

Rust on a garden gate.

The last log in the fire.

A yellow reactive dye with masstone L*51.0 a*47.0 b*60.0 (C*76.2, h°52). Peak absorption at 440 nm (2.0% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.973 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 50× tinting strength span across the series.

Peak 440nmK/S 23.93Span 50×r 0.9738 samples · masstone 4.00%
Yellow · 54°
#272625

NEGRO ASUFAST NVA 2000

Wet ironwood.

L*
15.2
a*
0.5
b*
0.7
C*
0.8
0255075100470 nm400500600700
Reflectance %Wavelength nm · 360–700

Wet ironwood.

A photographer's darkroom.

Ink before it touches the page.

A yellow reactive dye with masstone L*15.2 a*0.5 b*0.7 (C*0.8, h°54). Peak absorption at 470 nm (1.8% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.981 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 79× tinting strength span across the series.

Peak 470nmK/S 26.58Span 79×r 0.9818 samples · masstone 4.00%
Yellow · 63°
#EA7600

AMARILLO ASUFAST AGL

Mango skin.

L*
61.9
a*
39.5
b*
76.6
C*
86.2
0255075100430 nm400500600700
Reflectance %Wavelength nm · 360–700

Mango skin.

Brass left in the sun.

Saffron in a glass jar.

A yellow reactive dye with masstone L*61.9 a*39.5 b*76.6 (C*86.2, h°63). Peak absorption at 430 nm (2.1% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.945 — non-linear build-up, expect harder shade matching at extremes. Concentration range 0.02%–4.00%, a 53× tinting strength span across the series.

Peak 430nmK/S 23.37Span 52.8×r 0.9458 samples · masstone 4.00%
Yellow · 68°
#FF8E00

AMARILLO ASUFAST GRL

Marigold after the rain.

L*
69.9
a*
35.8
b*
90.3
C*
97.2
0255075100420 nm400500600700
Reflectance %Wavelength nm · 360–700

Marigold after the rain.

A taxi door in mid-afternoon.

The yolk of a duck egg.

A yellow reactive dye with masstone L*69.9 a*35.8 b*90.3 (C*97.2, h°68). Peak absorption at 420 nm (1.8% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.979 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 49× tinting strength span across the series.

Peak 420nmK/S 27.28Span 48.8×r 0.9798 samples · masstone 4.00%
Green · 79°
#FFB400

AMARILLO ASUFAST PG

Honeycomb held to the light.

L*
79.6
a*
20.3
b*
100.1
C*
102.1
0255075100410 nm400500600700
Reflectance %Wavelength nm · 360–700

Honeycomb held to the light.

A wheat field at noon.

Pollen on a black sleeve.

A green reactive dye with masstone L*79.6 a*20.3 b*100.1 (C*102.1, h°79). Peak absorption at 410 nm (1.9% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.983 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 48× tinting strength span across the series.

Peak 410nmK/S 24.92Span 47.9×r 0.9838 samples · masstone 4.00%
Blue · 205°
#2E3131

GRIS ASUFAST 4GL 300%

Wet slate.

L*
20.0
a*
-1.3
b*
-0.6
C*
1.4
0255075100610 nm400500600700
Reflectance %Wavelength nm · 360–700

Wet slate.

The North Sea in November.

Charcoal that has cooled.

A blue reactive dye with masstone L*20.0 a*-1.3 b*-0.6 (C*1.4, h°205). Peak absorption at 610 nm (2.7% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.979 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 53× tinting strength span across the series.

Peak 610nmK/S 17.5Span 53×r 0.9798 samples · masstone 4.00%
Blue · 233°
#0081AB

TURQUESA ASUFAST FBL 400%

A swimming pool at first light.

L*
48.1
a*
-26.7
b*
-34.9
C*
43.9
0255075100620 nm400500600700
Reflectance %Wavelength nm · 360–700

A swimming pool at first light.

Oxidized copper roof.

The eye of a peacock feather.

A blue reactive dye with masstone L*48.1 a*-26.7 b*-34.9 (C*43.9, h°233). Peak absorption at 620 nm (3.0% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.976 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 50× tinting strength span across the series.

Peak 620nmK/S 15.82Span 50.4×r 0.9768 samples · masstone 4.00%
Violet · 262°
#2B2B2C

NEGRO ASUFAST NVA EXTRA

The deep end at midnight.

L*
17.7
a*
-0.1
b*
-0.5
C*
0.5
0255075100610 nm400500600700
Reflectance %Wavelength nm · 360–700

The deep end at midnight.

Volcanic glass.

A starless sky.

A violet reactive dye with masstone L*17.7 a*-0.1 b*-0.5 (C*0.5, h°262). Peak absorption at 610 nm (2.4% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.978 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 73× tinting strength span across the series.

Peak 610nmK/S 20.05Span 72.8×r 0.9788 samples · masstone 4.00%
Violet · 267°
#004F84

AZUL BRI ASUFAST GLN 105

A gas flame's heart.

L*
31.6
a*
-2.1
b*
-37.1
C*
37.1
0255075100650 nm400500600700
Reflectance %Wavelength nm · 360–700

A gas flame's heart.

Indigo fresh from the vat.

A lapis stone underwater.

A violet reactive dye with masstone L*31.6 a*-2.1 b*-37.1 (C*37.1, h°267). Peak absorption at 650 nm (2.1% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.980 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 70× tinting strength span across the series.

Peak 650nmK/S 22.31Span 70.2×r 0.9808 samples · masstone 4.00%
Violet · 269°
#293340

GRIS ASUFAST LUZ CGLL 250%

A pigeon's wing.

L*
20.7
a*
-0.1
b*
-10.3
C*
10.3
0255075100620 nm400500600700
Reflectance %Wavelength nm · 360–700

A pigeon's wing.

Storm light over the highway.

An aluminum coffee pot.

A violet reactive dye with masstone L*20.7 a*-0.1 b*-10.3 (C*10.3, h°269). Peak absorption at 620 nm (2.5% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.970 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 52× tinting strength span across the series.

Peak 620nmK/S 19.05Span 51.7×r 0.9708 samples · masstone 4.00%
Violet · 275°
#1E2C41

AZUL ASUFAST 4BL 200%

A blueprint left in the sun.

L*
17.8
a*
1.2
b*
-15.5
C*
15.6
0255075100590 nm400500600700
Reflectance %Wavelength nm · 360–700

A blueprint left in the sun.

The hour before sunrise.

A police uniform's breast.

A violet reactive dye with masstone L*17.8 a*1.2 b*-15.5 (C*15.5, h°275). Peak absorption at 590 nm (1.8% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.973 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 55× tinting strength span across the series.

Peak 590nmK/S 27.27Span 55×r 0.9738 samples · masstone 4.00%
Violet · 277°
#233147

AZUL MARINO ASUFAST LFG

A sailor's collar.

L*
20.0
a*
1.9
b*
-16.4
C*
16.5
0255075100590 nm400500600700
Reflectance %Wavelength nm · 360–700

A sailor's collar.

The Atlantic in late October.

Ink dried on linen.

A violet reactive dye with masstone L*20.0 a*1.9 b*-16.4 (C*16.5, h°277). Peak absorption at 590 nm (2.1% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.971 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 52× tinting strength span across the series.

Peak 590nmK/S 22.28Span 51.6×r 0.9718 samples · masstone 4.00%
Violet · 279°
#21304C

AZUL MARINO ASUFAST BL 240%

A diplomat's overcoat.

L*
19.7
a*
3.3
b*
-19.5
C*
19.8
0255075100590 nm400500600700
Reflectance %Wavelength nm · 360–700

A diplomat's overcoat.

Deep harbor water.

An evening sky just before stars.

A violet reactive dye with masstone L*19.7 a*3.2 b*-19.5 (C*19.8, h°279). Peak absorption at 590 nm (2.0% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.978 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 47× tinting strength span across the series.

Peak 590nmK/S 23.85Span 47.1×r 0.9788 samples · masstone 4.00%
Violet · 280°
#08427D

AZUL ROYAL ASUFAST S

A peacock's neck.

L*
27.9
a*
7.0
b*
-38.6
C*
39.2
0255075100620 nm400500600700
Reflectance %Wavelength nm · 360–700

A peacock's neck.

Stained glass in a cathedral nave.

Lapis ground for a Renaissance painting.

A violet reactive dye with masstone L*27.9 a*7.0 b*-38.6 (C*39.2, h°280). Peak absorption at 620 nm (2.3% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.988 — near-perfect linear build-up — predictable in recipe formulation. Concentration range 0.02%–4.00%, a 67× tinting strength span across the series.

Peak 620nmK/S 20.65Span 67×r 0.9888 samples · masstone 4.00%
Violet · 285°
#232A41

AZUL ASUFAST BR 375

Denim worn for a decade.

L*
17.4
a*
4.2
b*
-15.6
C*
16.2
0255075100580 nm400500600700
Reflectance %Wavelength nm · 360–700

Denim worn for a decade.

A boatyard at twilight.

The cover of an old encyclopedia.

A violet reactive dye with masstone L*17.4 a*4.2 b*-15.6 (C*16.2, h°285). Peak absorption at 580 nm (1.9% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.967 — good build-up linearity, suitable for Kubelka-Munk recipe prediction. Concentration range 0.02%–4.00%, a 49× tinting strength span across the series.

Peak 580nmK/S 26.02Span 49.2×r 0.9678 samples · masstone 4.00%
Red · 358°
#63263D

RUBINOL ASUFAST BL

A glass of port held to candlelight.

L*
25.0
a*
30.5
b*
-0.9
C*
30.5
0255075100520 nm400500600700
Reflectance %Wavelength nm · 360–700

A glass of port held to candlelight.

Dried rose petals in a wooden bowl.

The seal on a velvet box.

A red reactive dye with masstone L*25.0 a*30.5 b*-0.9 (C*30.5, h°358). Peak absorption at 520 nm (2.1% reflectance at full strength), the spectral fingerprint of this colorant. K/S vs concentration correlation r=0.987 — near-perfect linear build-up — predictable in recipe formulation. Concentration range 0.02%–4.00%, a 63× tinting strength span across the series.

Peak 520nmK/S 23.12Span 62.7×r 0.9878 samples · masstone 4.00%