  RedGOLD searches for red-sequence galaxy overdensities while minimizing
contamination from dusty star-forming galaxies. It imposes an NFW profile and
calculates cluster detection significance and richness. We optimize these
latter two parameters using both simulations and X-ray detected cluster
catalogs, and obtain a catalog $\sim 80\%$ pure up to $z \sim 1$, and $\sim
100\%$ ($\sim 70\%$) complete at $z\le 0.6$ ( $z\lesssim1$) for galaxy clusters
with $M \gtrsim 10^{14}\ {\rm M_{\odot}}$ at the CFHT-LS Wide depth. In the
CFHT-LS W1, we detect 11 cluster candidates per $\rm deg^2$ out to $z\sim1.1$.
When we optimize both completeness and purity, RedGOLD obtains a cluster
catalog with higher completeness and purity than other public catalogs,
obtained using CFHT-LS W1 observations, for $M \gtrsim 10^{14}\ {\rm
M_{\odot}}$. We use X-ray detected cluster samples to extend the study of the
X-ray temperature-optical richness relation to a lower mass threshold, and find
a mass scatter at fixed richness of $\sigma_{lnM|\lambda}=0.39\pm0.07$ and
$\sigma_{lnM|\lambda}=0.30\pm0.13$ for the Gozaliasl et al. (2014) and Mehrtens
et al. (2012) samples. When considering similar mass ranges as previous work,
we recover a smaller scatter in mass at fixed richness. We recover $93\%$ of
the redMaPPer detections, and find that its richness estimates is on average
$\sim 40-50\%$ larger than ours at $z>0.3$. RedGOLD recovers X-ray cluster
spectroscopic redshifts at better than $5\%$ up to $z\sim1$, and the centers
within a few tens of arcseconds.
