I make my first steps with Drupal 8. I have a site with a header image. On a specific content type "Blog" I want to replace the standard header image with a node specific header image. So in the content type "Blog" i made a image field "field_headerimage". I also made it possible to make a content type specific page.html.twig, see https://drupal.stackexchange.com/a/141397/31981. This works.
Problem: I want to render field_headerimage in page.html.twig. There is a "node" variable, but it seems like this values aren't able to render.