Frequently stars are too bright for the CCD's "wells" to accomodate all of the photons; this causes signal to "bleed" along the adjacent rows and columns. Unlike diffraction spikes bleed only occurs when all, or part of, the star is visible on the image.
NON-REPORTABLE: Signal Bleed
CHARACTERISTICS:
Sharp, vertical/horizontal line(s) with high signal level relative to background (the bleed is the horizontal line that changes its extent on each pass - there is some evidence that the charge is is spilling vertically as well but that may be introduced in the electronic readout). Electron bleed always originates in a bright star or galaxy.
NON-REPORTABLE: Signal Bleed
CHARACTERISTICS:
Bleed favors one direction. Again, originates in a star.