To fill this gap, HyTech Pro created a free app and make available in AppExchange. This app is compatible with Lighting and Classic.
The benefit of using this app in Classic is the ability to change Salesforce's logo with your own company/organization logo, but you need to add a custom button (installed with the package) to the page layout.
In Lightning, you need to add "Printable View" action to "Salesforce1 & Lightning Actions" in object Page Layout. As you see from the screenshot below, the action will work even you are not opening the record details tab.
Type: Managed Package; AppExchange
Blog last update: 30 July 2017