A student determines the equilibrium constant, \(K_c\), for the reaction represented by the equation below.

\[ \text{Fe}^{3+}\text{(aq)} + \text{SCN}^-\text{(aq)} \rightleftharpoons \text{FeSCN}^{2+}\text{(aq)} \]

The student mixes solutions containing known initial concentrations of \(\text{Fe}^{3+}\text{(aq)}\) and \(\text{SCN}^-\text{(aq)}\). After equilibrium is established, the student transfers a portion of the mixture to a cuvette and measures its absorbance with a spectrophotometer to calculate \([\text{FeSCN}^{2+}]_{\text{eq}}\). If the student fails to wipe fingerprints from the optical faces of the cuvette before placing it in the spectrophotometer, how will this error affect the calculated value of \(K_c\)?