The prediction of uniform scaling of fluorescence after photoconversion holds. (A) Images of the cell from Fig. 3 before and 50 min after the photoconversion (PA) exposure. The lines in the images indicate positions along which fluorescence counts were acquired and compared in B. (B) In the top panel, the raw fluorescence counts along the lines indicated in A are plotted as a function of distance relative to the IS–OS junction. The bottom panel plots the fluorescence normalized to the average of the brightest 5% of the voxels in each 3-D scan (F₀).