I think that I have found an answer:  in the \setupinteraction command that manages URL&#39;s, hyperlinks, PDF properties, etc. include <div>color=,contrastcolor=,<div><br></div><div><br></div><div><div>\usemodule[letter]</div>

<div><br></div><div>%% Would like this URL to match the color of the return address (&quot;location&quot;)</div><div>\useURL[author-email][mailto:<a href="mailto:author@myhome.com">author@myhome.com</a>][][<a href="mailto:author@myhome.com">author@myhome.com</a>]</div>

<div>%% Would like this URL to match the color of the recipient&#39;s address (&quot;address&quot;)</div><div>\useURL[recipient-email][mailto:<a href="mailto:addressee@gmail.com">addressee@gmail.com</a>][][<a href="mailto:addressee@gmail.com">addressee@gmail.com</a>]</div>

<div>%% Would like this URL to match the color of the main body </div><div>\useURL[knuthbio][<a href="http://en.wikipedia.org/wiki/Donald_Knuth][][http://en.wikipedia.org/wiki/Donald_Knuth">http://en.wikipedia.org/wiki/Donald_Knuth][][http://en.wikipedia.org/wiki/Donald_Knuth</a>]</div>

<div><br></div><div>\setupinteraction[state=start,color=,contrastcolor=,style=normal]</div><div><br></div><div>\setupletter[</div><div>  name={Michael Ash},</div><div>  email={\from[author-email]}</div><div>  ]</div><div>

<br></div><div>\setupletter[signature={Michael Ash}]</div><div><br></div><div>\defineletterelement[layer][location][example]{\correspondenceparameter{name} \correspondenceparameter{email}\par}</div><div>\setupletterlayer[location][alternative=example,color=red]</div>

<div><br></div><div>\defineletterelement[layer][address][example]{\correspondenceparameter{toname}\par}</div><div>\setupletterlayer[address][alternative=example,color=blue]</div><div>                                     </div>

<div>\starttext</div><div>\startletter[</div><div>  toname={The Addressee\\\from[recipient-email]},</div><div>  opening={Dear Addressee:},</div><div>  closing={Best regards,}]</div><div><br></div><div>  Enjoy \from[knuthbio]</div>

<div><br></div><div>\stopletter</div><div>\stoptext</div></div><div><br></div><div><br><br><div class="gmail_quote">On Tue, Jul 30, 2013 at 5:57 PM, Michael Ash <span dir="ltr">&lt;<a href="mailto:mash@econs.umass.edu" target="_blank">mash@econs.umass.edu</a>&gt;</span> wrote:<br>

<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>I would like to change the color of URL&#39;s in parts of a document.</div><div><br></div><div>In particular I am using the letter module and would like to have the color of URL&#39;s match the color of text in the letterhead and then change to match the color in the main body of the letter.</div>


<div><br></div><div>I can set the URL color once with \setupinteraction but I do not see how to change it thereafter.</div><div><br></div><div>Thank you very much for your guidance.</div><div><br></div><div>Best,</div><div>


Michael</div><div><br></div><div><br></div><div><br></div><div>\usemodule[letter]</div><div><div><br></div><div>\setupinteraction[state=start,color=black]</div><div>%% \setupinteraction[state=start,color=red]</div><div><br>


</div><div>%% Would like this URL to match the color of the return address (&quot;location&quot;)</div><div>\useURL[author-email][mailto:<a href="mailto:mash@econs.umass.edu" target="_blank">mash@econs.umass.edu</a>][][<a href="mailto:mash@econs.umass.edu" target="_blank">mash@econs.umass.edu</a>]</div>


<div>%% Would like this URL to match the color of the recipient&#39;s address (&quot;address&quot;)</div><div>\useURL[recipient-email][mailto:<a href="mailto:addressee@gmail.com" target="_blank">addressee@gmail.com</a>][][<a href="mailto:addressee@gmail.com" target="_blank">addressee@gmail.com</a>]</div>


<div>%% Would like this URL to match the color of the main body </div><div>\useURL[knuthbio][<a href="http://en.wikipedia.org/wiki/Donald_Knuth%5D%5B%5D%5Bhttp://en.wikipedia.org/wiki/Donald_Knuth" target="_blank">http://en.wikipedia.org/wiki/Donald_Knuth][][http://en.wikipedia.org/wiki/Donald_Knuth</a>]</div>


<div><br></div><div>\setupletter[</div><div>  name={Michael Ash},</div><div>  email={\from[author-email]}</div><div>  ]</div><div><br></div><div>\setupletter[signature={Michael Ash}]</div><div><br></div><div>\defineletterelement[layer][location][example]{\correspondenceparameter{name} \correspondenceparameter{email}\par}</div>


<div>\setupletterlayer[location][alternative=example,color=red]</div><div><br></div><div>\defineletterelement[layer][address][example]{\correspondenceparameter{toname}\par}</div><div>\setupletterlayer[address][alternative=example,color=blue]</div>


<div>                                     </div><div>\starttext</div><div>\startletter[</div><div>  toname={The Addressee\\\from[recipient-email]},</div><div>  opening={Dear Addressee:},</div><div>  closing={Best regards,}]</div>


<div><br></div><div>  Enjoy \from[knuthbio]</div><div><br></div><div>\stopletter</div><div>\stoptext</div></div><div><br></div>
</blockquote></div><br><br clear="all"><div><br></div>-- <br>Michael Ash, Chair, Department of Economics<div>Professor of Economics and Public Policy         <br>University of Massachusetts Amherst<br>Amherst, MA 01003<br>

Email <a href="mailto:mash@econs.umass.edu" target="_blank">mash@econs.umass.edu</a><br>Tel +1-413-545-2590 Twitter <a href="https://twitter.com/michaelaoash" target="_blank">https://twitter.com/michaelaoash</a></div>
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