Additive and Subtractive Mixing Questions and Answers

Answer: C

Both are true and the reason gives the reason for the fourth ink, and it also saves ink and improves text sharpness. The four colour process is standard for exactly these reasons. Cost, sharpness and depth all improve together.

Answer: D

Correct answer: 1 and 2 only

Statements 1 and 2 are the real reasons for the fourth ink: three-colour black is muddy and expensive in ink, and text printed in three inks needs perfect registration to look sharp. Statement 3 overstates the case - the three primaries do produce dark colours, just not a satisfactory neutral black.

Answer: A

They sit opposite one another through the white point on a chromaticity diagram. Every colour has a complement, though for the non-spectral purples it is a spectral colour rather than the reverse. Complements sit opposite through the white point.

Answer: B

The first three pairs are the additive and subtractive primaries paired off. Complementarity is defined by additive mixing to a neutral rather than by any artistic convention. Additive mixing to neutral is the definition.

Answer: C

The complements of the greens lie among the non-spectral purples. Only part of the spectrum has a spectral colour as its complement. The greens are complemented by the purples. Only part of the spectrum has a spectral complement.

Answer: D

Both are true and the reason gives the geometry, and the purple line is not part of the spectrum. Greens are the region for which this occurs throughout. The purple line lies outside the spectrum. Greens are complemented by non-spectral colours.

Answer: A

Correct answer: a colour match is unaffected by adding the same light to both fields

This is the additivity law, and with the proportionality and associativity laws it establishes that additive mixing behaves linearly. That linearity is what permits tristimulus values to be added, scaled and transformed as ordinary vectors, and it is the foundation on which the whole CIE system rests.

Answer: B

Correct answer: 1 and 2 only

Statements 1 and 2 are correct: Grassmann’s laws establish linearity, and the arithmetic of tristimulus values depends on it. Statement 3 is the important limitation - subtractive mixing is multiplicative rather than additive, so the laws do not carry across, which is exactly why colourant mixing needs Kubelka Munk or Beer rather than simple addition.

Answer: C

Both are true and the reason gives the justification, and the arithmetic is straightforward. Subtractive mixing offers no comparable simplicity. Transmittances multiply rather than adding. Additive arithmetic does not carry over.

Answer: D

Correct answer: absorption and scattering combine multiplicatively rather than additively

Light passing through successive absorbing layers has its intensity multiplied by each transmittance in turn, so the reflectance of a mixture is not the sum of the components’ reflectances. Transforming to absorbance for transparent media, or to K over S for opaque ones, restores additivity and makes the arithmetic tractable.