Metamerism Questions and Answers

Answer: A

Correct answer: use the same colourants as the standard in the same proportions

If the reflectance curves are identical, the match holds under every illuminant and every observer, because there is no spectral difference to be revealed. Every other approach controls the symptom rather than the cause: minimising the difference under one illuminant is precisely how metameric recipes come to be chosen.

Answer: B

Both are true and the reason gives the mechanism, and the tristimulus match can still be achieved. It is the spectral curve that will differ. A tristimulus match remains achievable nonetheless. The curve is what will differ between them.

Answer: C

Correct answer: 1 and 2 only

Statements 1 and 2 are correct: the standard’s own colourants reproduce its curve and give an unconditional match, and any substitution changes the curve and introduces metamerism. Statement 3 is the error that recipe formulation software can encourage - many recipes reach the same three numbers, and they differ enormously in how well they hold up under a change of light.

Answer: D

Spectral matching is offered alongside tristimulus matching in most systems. It generally requires the same colourants and gives a more expensive recipe. Spectral matching is offered by most systems. The recipe is usually the more expensive one.

Answer: A

Both are true and the reason gives the cost, and the customer must decide which matters more. Cheapness and robustness pull in opposite directions here. The customer must decide which matters more. Cost and durability pull against each other.

Answer: B

Correct answer: A-2, B-4, C-1, D-3

The four are distinguished by what varies and what stays fixed. Metamerism is two samples across two illuminants; colour inconstancy is one sample across two illuminants; observer metamerism is two samples across two observers; and colour constancy is the perceptual mechanism that discounts the illuminant so that a surface looks much the same under both.

Answer: C

Both are true and the reason gives the distinction, and both members of a metameric pair may also be inconstant. The two properties are logically independent. Either may occur without the other. The two properties are logically separate.

Answer: D

The first two are correct and distinguish the two properties. The third does not follow, since a pair may separate while each member stays reasonably constant. The two properties are separate. Neither implies the other in any way.

Answer: A

It describes the eye's tendency to discount the illuminant. Colour inconstancy by contrast is a property of the sample and its colourants. One belongs to the eye and one to the material. Constancy and inconstancy are easily confused.

Answer: B

Normal variation in cone sensitivities is enough to break a marginal match. Instrumental tolerances agreed in advance are the usual safeguard. Normal cone variation breaks marginal matches. Agreed instrumental tolerances are the safeguard.