Which of the following factors does NOT influence price elasticity of demand?

The price elasticity of demand measures how sensitive the quantity demanded of a good is to a change in its price. Certain factors critically determine this sensitivity.

The availability of substitutes is a crucial factor; when there are many substitutes available for a product, consumers can easily switch to these alternatives if the price of the original product increases. This leads to a higher elasticity of demand.

The distinction between necessities and luxuries also plays a significant role. Necessities tend to have inelastic demand because consumers will continue to buy them regardless of price changes, while luxuries are more elastic since consumers can forego them when prices rise.

The proportion of income spent on a good affects elasticity as well; if a significant portion of income is spent on a good, price changes will greatly affect demand and thus lead to higher elasticity. Conversely, if a good comprises a small fraction of income, demand tends to be more inelastic.

However, the color of the packaging does not traditionally influence price elasticity of demand in a meaningful economic sense. While it might affect consumer preferences or perceived value, it is not a fundamental determinant of how responsive consumers are to price changes. Therefore, it is correctly identified as a factor that does not influence price elasticity of demand.