Show entries by one author, then split into categories

I have many authors, and each of them create entries that are categorized into a set of common categories, such as red, green and blue. I want to show all the entries by a single author, then offer links to each category, that when clicked show only that author’s entries in the selected category.

So like:
Bob Smith: Red (show bob’s red entries) Green (show bob’s green entries) Blue (show bob’s blue entries)

So I show all the author’s entries using this:

{exp:channel:entries channel="art" author_id="{segment_3}" dynamic="no" limit="20" paginate="both"}

Which gives me a URL like: mysite.com/art/artist/26. Where 26 is the author_id. I found that if I did not use dynamic=”no”, it would display nothing. So just showing the entries from this author works.

Then I wanted to show all that author’s items in a particular category using these links:

{exp:channel:categories channel="art" category_group="3" style="linear"}
      <li><a href="http://{path=art/artist/{segment_3}}">{category_name}</a></li>
{/exp:channel:categories}

So the categories display correctly, and the links to them look like this: mysite.com/art/artist/26/C24.

But I’m having trouble limiting them by BOTH author and category. Having the “C24” or whatever category ID at the end of the URL does nothing - it just still shows all the entries by that author from any category. Obviously, this needs dynamic=”yes” in order to work, so it seems like I can’t have my cake and eat it too.

Am I going about it backwards? Should I be somehow designating the category first, setting dynamic=”yes” and then finding another way to limit by the author_id that does not require dynamic=”no”?

Or do I need some kind of SQL query to pull the author_id ?

Would love some help if anyone has advice. THanks!