  We report g-r and r-i new colors for 21 Saturn Irregular Satellites, among
them, 4 previously unreported. This is the highest number of Saturn Irregular
satellites reported in a single survey. These satellites were measured by
"stacking" their observations to increase their signal without trailing. This
work describes a novel processing algorithm that enables the detection of faint
sources under significant background noise and in front of a severely crowded
field.
  Our survey shows these new color measurements of Saturn Irregular Satellites
are consistent with other Irregular Satellites populations as found in previous
works and reinforcing the observation that the lack of ultra red objects among
the irregular satellites is a real feature that separates them from the
trans-Neptunian objects (their posited source population).
