Paint constituents — function of pigment in a coating system In a conventional paint, the pigment primarily provides:

Introduction / Context:
Paint performance depends on the interplay of pigment, binder, solvent, and additives. Recognizing the core function of pigment helps with specification and troubleshooting for color, coverage, and film appearance.

Given Data / Assumptions:

• Pigments are finely ground insoluble particles (e.g., TiO2, iron oxides).
• Binder (vehicle) forms the film and determines durability and gloss potential.
• Application method and film thickness affect smoothness and sheen.

Concept / Approach:
Pigments impart color and provide hiding power by scattering and absorbing light. Opacity arises from pigment refractive index difference with the binder and proper dispersion. Durability and gloss are mainly governed by the binder chemistry and formulation, not the pigment alone (though pigments can influence durability secondarily).

Step-by-Step Solution:
Identify pigment role: color + opacity.Separate binder functions: film formation, adhesion, gloss potential.Acknowledge that application and surface prep affect smoothness, not pigment alone.

Verification / Alternative check:
Technical datasheets list hiding power and color strength under pigment properties; gloss and durability are linked to resin system and curing.

Why Other Options Are Wrong:
Durability via crosslinking is binder-driven. Surface smoothness/gloss depend on binder rheology, leveling, and application conditions more than pigment alone. None is incorrect since pigment's color/opacity function is fundamental.

Common Pitfalls:
Assuming higher pigment automatically means better durability; excessive pigment volume concentration can reduce film strength.

Final Answer:
Colour and hiding power (opacity)