METAMERISM or things that go weird in the light

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Shopping

Have you ever compared two garments in a

store and decided to buy because they matched

But when you left the store and went into daylight

they no longer matched and looked quite different

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Metamerism

Same colors under

department store

illumination

Different color under

daylight

If so, then you have seen an optical phenomenon called metamerism.

Metamerism occurs when you see two samples match under one light

source (illuminant) and not match under another

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Metamerism

Definition:

If a pair of samples (standard color swatch vs dyed one)

looks identical under a particular illuminant (e.g.D65,A,TL

84, CWF), but different under another light source, the

samples are described as metameric.

This is caused by the different spectral reflectance

properties of the two samples.

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Shade under TL 84, department store light

Brand standard Dyed sample

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Brand standard Dyed sample

Shade under D65, daylight

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Reflectance curves of metameric colors

0

0.2

0.4

0.6

0.8

400 450 500 550 600 650 700

Wavelength [nm]

Refl

ecta

nce f

acto

r b

eta

Brand standard

dyed sample

The spectral reflectance distribution

of the two samples differ slightly and

the curves cross in at least two

regions.

By illuminating them with different

light sources, the visual differences

between the two samples can be

witnessed and even exaggerated

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AVITERA SE / NOVACRON FN, Yellow area

1 2

3

1 Yellow SE

2 Yellow FN-2R

3 Yellow F-4G

From D65 to TL84

From D65 to A

Yellow SE and Yellow FN-2R do behave the same way under TL84

and A illuminant.

Yellow F-4G is different and is used to correct metamerism

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1 Red SE

2 Red FN-R-01

3 Red FN-2BL

From D65 to TL84

From D65 to A

AVITERA SE / NOVACRON FN, Red area

1

2

3

Red SE and Red FN-R-01 do behave the same way under TL84 and A

illuminant.

Red FN-2BL is somewhat different under A illuminant

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1 Orange SE

2 Cardinal SE

3 Orange FN-R

4 Scarlet FN-6G

5 Brill. Red FN-3GL

From D65 to TL84

From D65 to A

AVITERA SE / NOVACRON FN, Orange, Brill Red area

1

2

4

3

5

Orange SE and Orange FN-R do behave the same way under TL84, but Orange

SE turns to the opposite direction compared to Orange FN-R under A

illuminant which could be an advantage in terms of metamerism.

Cardinal SE and Brill Red FN-3GL have a very similar behavior

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1 Light Blue SE

2 Blue SE

3 Blue FN-R

4 Brill Blue FN-G

From D65 to TL84

From D65 to A

AVITERA SE / NOVACRON FN, Blue area

1

2

4

3

Light Blue SE, Blue SE, and Blue FN-R do also behave the same way.

Brill. Blue FN-G is clearly different and this is also the reason why this

dyestuff is well known to correct metamerism issues

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1 Deep Blue SE

2 Navy SE

3 Navy FN-BN

From D65 to TL84

From D65 to A

AVITERA SE / NOVACRON FN, Navy area

1 2

3

Deep Blue SE and Navy FN-BN have the same behavior, Deep Blue SE has

a stronger impact under A illuminant to the green side

Navy SE turns to the opposite direction under TL84 which could be an

advantage in terms of metamerism.

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Conclusion

AVITERA SE dyes behave very similar under different light sources

compared to our NOVACRON FN and classical trichromatic dyes from

competition, thus we should get more or less the same results

Exceptions are Yellow F-4G and Brill. Blue FN-G which are well known to

correct meatmeric issues.

The ideal, often most robust and fast- trichromy used in dye mills do not

always allow a non- metameric shade compared to such standards, simply

because the initial color choice of a designer is not based on a textile dyers

logic.

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Designers chose their shades from different supports such as paper, foils or plastic colored with completely different dyes/pigments which have nothing to do with the dyes used in the textile industry

Examples :

From a PANTONE color selector, in which case the color has been obtained by

printing on paper, with a trichromy of:

=> greenish yellow („Lemon“)

=> pinkish red („Magenta“)

=> turquoise („ Cyan“)

This is much different from a typical textile trichromy , usually based upon:

=> golden yellow

=> bluish red

=> reddish or neutral blue or navy

Source of metamerism problems between Brand standard sample and actual dye house dyeing

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Brand standards made up on a different fabric such as PES, PA or

PAN dyed with completely different dye classes

For cotton color standards production often exotic mixes are used for

dyeing and shading ( turquoise, lemon, bright reds and scarlets ) which

makes it almost impossible to achieve the required metamerism level

with a classical trichromy

Source of metamerism problems between Brand standard sample and actual dye house dyeing