Spf is an easy-to-use, open-source app that adds a semi-opaque layer over your screen to better show highlights and low-visibility elements in your designs or presentations when projected onto a screen or external monitor.
While working at Facebook we had a little tool called Preso Saver, created by my friend and former mentor Dirk Stoop (former co-founder of Sofa). When I left Facebook, I found myself in meetings and presentations where the screens I was presenting on weren't calibrated or capable of showing off the fine details of my work.
Light grays or hairlines in designs were too washed-out and therefore invisible on the screen. Highlights of elements—such as composed glare or highlight states for interactive features—were practically invisible. To help solve my problem, I re-created the Preso Saver tool from Facebook (with Dirk's blessing). The title "Spf" comes from "Screen polarization function," a semi-trolling title that stems from the original concept for this tool as being a "Polarizer" of sorts.
Spf gives you four preset shades of darkness and a test mode to ensure the app works when presenting or projecting.
The tool is lightweight and remarkably simple, so much so that it only made sense to open source so others can use it and customize it to meet their needs better. You can find the complete source code and resource files on GitHub.