As you know, Web.ApplyTheme method applies a theme with the specified components to this site.
For more information refer –
Here fontSchemeUrl and backgroundImageUrl parameters can accept null values. But when I tried to pass $null or null or Empty String to these two parameters via PowerShell, I got the following error:
“Exception calling “ApplyTheme” with “4” argument(s): “The ‘fontSchemeUrl’ argument is invalid.”.Exception.Message”
Then i tried with Out-Null instead of $null or null or Empty String. Trust me it worked like a charm.
Actually the Out-Null cmdlet deletes output instead of sending it down the pipeline.
This is my final code.
Hope this helps.