Convert rgb decimals to RGB integers with xcolor

Question

Using xcolor I have a color ared defined as in the following:

\documentclass[12pt]{article}
\usepackage[names,dvipsnames,named]{xcolor}
\definecolor{ared}{rgb}{.647,.129,.149}

\begin{document}

\huge\textsf{\textbf{\textcolor{ared}{HELLO}}}.

\end{document}

Question: How do I find the 3-element integer equivalent of that color?

The reason I ask: I want to use an app to find other colors that harmonize with that reddish color, but to do so they demand I specify the red as a triple of integers.

I tried to do this using a "color picker" app, but when I display a blob of the color on-screen as LaTeX output, the meter gives me rather different decimal values from the .647,.129,.149 I actually start with.

Note: This particular red was shown in the source for memoir's chapter style pederson" by Lars Madsen in the 2006 package from/info/latex-samples/MemoirChapStyles. And thememoirdocumentationmemmancredits Madsen for that "attractive color" for chapter numbers and titles in thepederson` style. (Thank you David Carlisle for locating the link to Madsen for me.)

Answer 1

As commented, you can use \convertcolorspec, but for check the values of several colors with several color models, nothing better than the testcolors environment:

\documentclass[12pt]{article}
\usepackage[names,svgnames,dvipsnames,named]{xcolor}
\definecolor{ared}{rgb}{.647,.129,.149}
\begin{document}
\begin{testcolors}[RGB,HTML,HSB]
\testcolor{ared}
\testcolor{DarkRed}
\end{testcolors}
\end{document}