Figure 3 of Govardovskii, Mol Vis 2009; 15:1717-1729.

Figure 3. Two ways to eliminate the Meta III artifact. In A, dark and postbleach spectra were recorded at acidic pH. The amount of Meta III formed was greatly reduced, and its spectrum narrowed. Thus tracing rhodopsin diffusion at λ > 550 was only marginally compromised by Meta III formation. Spectra represent average of six cells. In B, recordings were made in standard Ringer at pH 7.5 with addition of 50 mM of freshly neutralized hydroxylamine. Conversion of metaproducts to retinaloxime was complete at 30 s postbleach, and afterwards metaproducts did not contribute to absorbance changes. Spectra represent average of five cells.