  Dynamically excited objects within the Kuiper belt show a bimodal
distribution in their surface colors, and these differing surface colors may be
a tracer of where these objects formed. In this work we explore radial color
distributions in the primordial planetesimal disk and implications for the
positions of ice line/color transitions within the Kuiper belt's progenitor
populations. We combine a full dynamical model of the Kuiper belt's evolution
due to Neptune's migration with precise surface colors measured by the Colours
of the Outer Solar System Origins Survey in order to examine the true color
ratios within the Kuiper belt and the ice lines within the primordial disk. We
investigate the position of a dominant, surface color changing ice-line, with
two possible surface color layouts within the initial disk; (1) inner neutral
surfaces and outer red, and (2) inner red surfaces and outer neutral. We
performed simulations with a primordial disk that truncates at 30 au. By
radially stepping the color transition out through 0.5 au intervals we show
that both disk configurations are consistent with the observed color fraction.
For an inner neutral, outer red primordial disk we find that the color
transition can be at $28^{+2}_{-3}$ au at a 95% confidence level. For an inner
red, outer neutral primordial disk the color transition can be at
$27^{+3}_{-3}$ au at a 95% confidence level.
