g :  0.0031 mag (median), 0.0031 mag (mean)
r :  0.00081 mag (median),  0.00055 mag (mean)
z : -0.00054 mag (median), -0.00046 mag (mean)

/global/homes/a/ameisner/idl/decam/colortransform_ps12bok.pro
/global/homes/a/ameisner/idl/decam/colortransform_ps12mayall.pro