I thought a privacy screen protector was a smart idea - until I put one on my Galaxy S25 Ultra

"Considering how much personal information we store on our smartphones, I wouldn't be surprised if the demand for privacy screen protectors is at an all-time high. From bank statements to email credentials to photos and videos, the need to keep our digital footprint safe and secure, especially from the prying eyes of strangers, has never been more necessary. Also: Stop putting your phone screen-side up on the table - why you'll be glad you did Earlier this year, I gave the privacy-enhanced accessory a try, installing on my Galaxy S25 Ultra. The installation process was the same as any other modern-day screen protector, with a guide tray that you set your Samsung phone into for near-perfect placement."

"The ESR screen protector worked exactly as intended: when staring at the S25 Ultra from the center, the display still looked bright, sharp, and vibrant. When I moved my head just a little bit to the left or right, the image quickly faded into black, as if the phone screen wasn't turned on. The two-way privacy filter worked like magic, and for the first time in a long time, I felt comfortable answering work emails and exchanging personal messages while on the New York City subway. Even if a stranger wanted to peek, they couldn't. Things took a turn when I was catching up on Lakers highlights -- and the display suddenly dimmed itself. Sure, my brightness setting is typically set to auto, but unless I'm moving between two drastically different lighting environments, which I wasn't at the time, the shift in brightness should never be as dramatic as it was. My first assumption was that perhaps my shadow was cast over the phone's light sensor, causing it to dim the screen."

A privacy screen protector was installed on a Galaxy S25 Ultra using a guide tray for near-perfect placement and easy bubble removal. The tempered glass maintained center-view brightness and clarity while quickly darkening the display from side angles. The two-way privacy filter prevented shoulder surfing, enabling comfortable handling of emails and messages in public transit. During video playback the display unexpectedly dimmed despite typical auto-brightness behavior. The initial hypothesis attributed the dimming to a shadow over the phone's ambient light sensor, since the brightness shift was far more dramatic than normal automatic adjustments.

Read at ZDNET