Brightness

Make sure the brightness is propagated to all rendering engines used
To Test
 * Open a big image e.g. 4kx4k.jpeg in the full viewer
 * Display settings and click on Advanced tab
 * Modify the brightness.
 * Make sure all the tiles are updated.
 * Save the settings
 * Re-open the image 

see https://trac.openmicroscopy.org.uk/ome/ticket/11705