corfred

Oh golly!

global $haspaintings, $hasphotography, $hasobjects;

That did the trick! Thank you so so so much!

Ha I will forgive you I guess.

500 Error is gone! But, no sidebar is being displayed.

From sidebar.php

<div id="secondary" class="widget-area" role="complementary">
				<?php
				if (is_archive()) {
				 	 if ($haspaintings) {
					 	dynamic_sidebar( 'paintings-sidebar' );
					 }
					 if ($hasphotography) {
						dynamic_sidebar( 'photography-sidebar' );
					 }
					 if ($hasobjects) {
					 	dynamic_sidebar( 'objects-sidebar' );
					 }
				 } else {
					dynamic_sidebar( 'sidebar-1' );
				 }
				 ?>
		</div><!-- #secondary -->

Still getting the error

PHP Parse error: syntax error, unexpected ‘=’ in /wp-content/themes/twentytwelve/archive.php on line 26

That is the line -> $has-paintings = false;

So would this be right? or am I declaring the flags in the wrong place … because I am getting a server error everywhere that I attempt to place them on this page.

By the way, I really appreciate your help.

<section id="primary" class="site-content">
		<div id="content" role="main">

			<?php
			$has-paintings = false;
			$has-photographs = false;
			$has-objects = false;
			/* Start the Loop */
			if ( have_posts() ) : while ( have_posts() ) : the_post();

				 if (in_category( 'paintings' )) {
				    $has-paintings = true;
				  }
				  if (in_category( 'photography' )) {
				    $has-photographs = true;
				  }
				  if (in_category( 'objects' )) {
				    $has-objects = true;
				  } 

				get_template_part( 'content', get_post_format() );

			endwhile;

			?>

		<?php else : ?>
			<?php get_template_part( 'content', 'none' ); ?>
		<?php endif; ?>

		</div><!-- #content -->
	</section><!-- #primary -->

Thanks for the response!
I do have that closing curly bracket.
And I was afraid that was going to be the solution as it is a bit above my knowledge level.
It makes sense that it looks at the current post.

I have been trying to find a way for it to scan all of the posts on that page and count if the any of those three categories has a count > 0, and if TRUE, add that sidebar.

Does it sound like I am on the right track with that?