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The Tip of the Red Giant Branch (TRGB) is an apparent discontinuity in thecolor-magnitude diagram (CMD) along the giant branch due to the end of the redgiant evolutionary phase and is used to measure distances in the localuniverse. In practice, the tip is often fuzzy and its localization via edgedetection response (EDR) relies on several methods applied on a case-by-casebasis. It is hard to evaluate how individual choices affect a distanceestimation using only a single host field while also avoiding confirmationbias. To devise a standardized approach, we compare unsupervised, algorithmicanalyses of the TRGB in multiple halo fields per galaxy, up to 11 fields for asingle host and 50 fields across 10 galaxies, using high signal-to-noisestellar photometry obtained by the GHOSTS survey with the Hubble SpaceTelescope. We first optimize methods for the lowest field-to-field dispersionincluding spatial filtering to remove star forming regions, smoothing andweighting of the luminosity function, selection of the RGB by color, and tipselection based on the number of likely RGB stars and the ratio of stars aboveversus below the tip ($R$). We find $R$, which we call the tip `contrast', tobe the most important indicator of the quality of EDR measurements; we findthat field-to-field EDR repeatability varies from 0.3 mag to $\leq$ 0.05 magfor $R=4$ to 7, respectively, though less than half the fields reach the higherquality. Further, we find that $R$, which varies with the age/metallicity ofthe stellar population based on models, correlates with the magnitude of thetip (and after accounting for low internal extinction), i.e., a tip-contrastrelation with slope of $-0.023\pm0.0046$ mag/ratio, a $\sim 5\sigma$ resultthat improves standardization of the TRGB. We discuss the value of consistentTRGB standardization across rungs for robust distance ladder measurements.

Comparative Analysis of TRGBs (CATs) from Unsupervised, Multi-Halo-Field Measurements: Contrast is Key