The percentage of bright spots which are not clogs (α) is based on the analysis in Fig. . It is the fraction of bright spots or streaks outside the w(x) ± 2d p limit. The α fraction of bright spots are nonclogs; not associated with any clog in the microchannels and likely constituted by individual particles adhered to the channel walls, even in pristine flow tests. There is, approximately, an order of magnitude increase in α in both conditions where deposition is induced, compared to pristine controls (Table ). Only ∼3% of the clogs are nonclogs in pristine flow tests. However, α is more than 35% where aggregation or adhesive interactions are induced.