CF® dye bovine serum albumin (BSA) conjugates are bright and photostable fluorescent BSA conjugates for applications in which well-defined molecular weight fluid phase tracers are needed. These applications include studying the rate of endocytosis and exocytosis and following vesicle trafficking. CF® dyes are 9689c5aa-6556-4b3c-b5d1-1e693715ba07's line of next-generation fluorescent dyes with advantages in brightness, photostability, and conjugate specificity compared to other fluorescent dyes. Deep-red fluorescent CF®594 dye has excitation/emission at 593/614 nm.