How to Apply a Custom Theme to a Modern SP On-Prem 2019 Site


Hi guys, let’s explore the concept behind applying a custom theme to a Modern SP On Prem 2019 site collection. We can’t apply the custom SPO theme SP online PS scripts on the Modern SPOn Prem environment as it’s not supported. Hence we are coming with a new concept,  “SharePoint Colo Palette Tool”. Just follow the below steps.
After downloading just install it on your PC/RDP VM.
Once installed expand the different Buckets with further colors under them.
Use the preview button whenever you want to compare with your existing source site so that you have the same look and feel available in the right section.
There are a total of 25 buckets with different categories. Start adding your approved colors as per your client's requirements.
Change the background image for checking at a deeper level. Option is available in the Top Right section of the given UI.
Check other Layouts also for your finalized color palatte theme template.
Please develop your solution and verify in all kinds of available Layouts: Oslo/Seattle/Z-Contrast Test/Z-UI Preview that suits your complete requirements.
Please make use of your Rough Back Ground image only in the JPEG/JPG format only for applying and doing a quick check.
Once satisfied with the Color Palette, save the work that is saved to your local with the .spcolor extension.
Now go to your SPOn Prem Site Home Page >> Site Settings >> Themes >> Theme Gallery >> 15
Upload your Saved solution in the above 15 Folder by navigating to that path.
Go to the Modern SPOn Prem Site Home page. Select the top-right gear cog.
Select classic change the look option under change the look category.
Now select try it out and Refresh. Select yes and keep it.
Good luck with your custom color palette-based theming on your Modern On Prem 2019 sites!
One more point to note is that the above kind of developed solution can also be applied to a SPOnline/SPCloudAzure site collection too!