Computer Colour Matching Questions and Answers

Answer: C

Correct answer: dyeings or samples of each colourant at several concentrations

The database must capture how \( K/S \) varies with concentration, which requires several depths of each colourant - typically four to six from pale to deep - prepared by the same process and on the same substrate as production. A single full-depth dyeing gives one point on a curve that is not straight.

Answer: D

Both are true and the reason gives the specificity, and process conditions matter too. A database cannot simply be transferred between installations. Substrate and process both enter the data. Local calibration cannot be avoided.

Answer: A

Correct answer: 1 and 2 only

Statements 1 and 2 are correct: several concentrations are needed to establish the curve, and the result belongs to that substrate and that process. Statement 3 is the tempting shortcut that does not work - a supplier’s data was generated on their substrate under their conditions, and the same dye on a different cloth or a different liquor ratio behaves differently.

Answer: B

Enough points are needed to define the curvature across the useful range. Too few leaves the relationship poorly determined at the extremes. Curvature must be captured across the range. Too few points leave the extremes uncertain.

Answer: C

The simple proportionality breaks down as the substrate approaches saturation. Software applies a correction function fitted to the calibration data. Linearity fails as the substrate saturates. A fitted correction restores the prediction.

Answer: D

Correct answer: Both A and R are true, and R is the correct explanation of A

Both are true and the reason gives the mechanism. At deep shades the dye no longer distributes as it does at pale depths and the relation between \( K/S \) and concentration flattens, so a straight-line extrapolation overpredicts the depth achieved. The software fits the measured curve or applies a correction rather than assuming proportionality throughout.

Answer: A

Three gives enough freedom to match the tristimulus values in most cases. More colourants improve the spectral fit but complicate production control. Three suffices for the tristimulus values. A fourth improves the spectral fit.

Answer: B

Both are true and the reason gives the mechanism, and the trial is the cheapest place to discover the discrepancy. Prediction is only as good as the database behind it, and dye lot strength, substrate absorbency and liquor ratio all drift over time. A small laboratory dyeing costs very little; a rejected bulk lot costs a great deal.

Answer: C

The first two are correct and describe the trade-off. The third ignores the cost and the production difficulty that each additional colourant brings. Cost and complexity both rise with the count. More is not automatically better here.

Answer: D

The colourist chooses among them on grounds the software cannot judge. Availability, fastness and process suitability all enter that decision. The software cannot weigh these itself. The colourist supplies the missing knowledge.