Spf 1.2.1 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. This free Mac application is a product of Tanner Christensen. The software relates to System Tools.
From the developer:
Spf is an easy-to-use, open source app that adds a semi-opaque layer over your screen in order to better show highlights and low-visibility elements in your designs or presentations when projected onto a screen or external monitor. Spf gives you four preset shades of darkness and a test mode for ensuring the app is working properly when presenting or projecting.
You may want to check out more software for Mac, such as Mireka, which might be similar to Spf.