SharePoint 2019 on-premises custom theme using a PowerShell script

[Matthew Carter]

I am on SharePoint 2019 on-premises with May 2023 CU.  I see Gear, Change the Look.  Current theme.  I want to set COMPANYTHEMEHERE as the theme.  I have done so in SharePoint Online however I have to use PNP and I do NOT have that on-premises.

I go to help on the SharePoint 2019 on-premises site and it takes me to - SharePoint site theming.

https://learn.microsoft.com/en-us/sharepoint/dev/declarative-customization/site-theming/sharepoint-s...

I have gone to the Theme Generator Tool - https://aka.ms/themedesigner and I have a basic theme.  I am only changing the color of our site from SharePoint teal to our company branded color.

I go to the SharePoint site theming: PowerShell cmdlets:

https://learn.microsoft.com/en-us/sharepoint/dev/declarative-customization/site-theming/sharepoint-s...

THIS is taking me to information about SharePoint ONLINE and NOT on-premises, which in SharePoint 2019 I am on-premises!

What am I missing as I would like for a way to update the color of the theme on-premises.

[#2]

@Matthew Carter , Did you find a solution for this? I have a same issue.

[#3]

@Matthew Carter 

I do not believe it is possible to deploy a custom theme to on premise using PowerShell. What I have done in the past is to design my theme using the SharePoint Color Palette Tool. Then I modify the default palette to create my own. Thhis tool is no longer available from Microsoft, but can be found in a Reddit thread here: https://www.reddit.com/r/sharepoint/comments/129els4/anyone_have_the_old_sharepoint_color_palette_to... (If you cannot download it, you might have to simply download and edit an existing .spcolor file from the Themes folder in a text editor.) Then I upload it to the Themes folder under Site Settings. Then I go through the classic Change the Look options to select the color scheme I have created.