The homepage slideshow overlay creates an automatic vignette effect at the top and bottom of your homepage slideshow, adding a dark fade to these areas so the title and text information can be seen and read better.
How does the slideshow banner looks like with an overlay mask?
Homepage slideshow banner with overlay mask:
Homepage slideshow banner without overlay mask:
Remove the slideshow overlay from your homepage banner
To disable this overlay effect, go to your homepage website CMS's settings (Settings > Settings > Homepage) and turn on 'Hide homepage slideshow overlay'.
You will find this setting under the slideshow section.
Edit your homepage
See this guide for more information on editing your homepage layout and display settings.