What is a PSE Test?
If you’ve ever had a video rejected for “failing the Harding test” or a “PSE failure,” you’re not alone. But what does that actually mean—and why does it matter?
Let’s break it down in plain English.
What is a PSE Test?
PSE stands for Photosensitive Epilepsy, a medical condition where flashing lights or certain visual patterns can trigger seizures in some individuals. To protect viewers, broadcasters, especially in the UK and Europe, require that all video content must pass a test to ensure it won’t cause a reaction to any of its viewers.
That’s where the PSE test comes in.
This automated check analyses your video for:
Rapid flashes - especially white, red or high-contrast flashes
Stripes or patterning - that may cause visual stress
Colour transitions and sudden luminance changes - that could trigger sensitivities
In the UK, this standard has been enforced by Ofcom for many years (since 1993 specifically), and it applies to all broadcast content, including:
TV programmes
Commercials and sponsorships segments
Music videos
Promos and trailers
And yes—even re-edits or re-versioned content must be re-tested and delivered with a pass certificate ✅
The “Harding Test”:
The term “Harding test” refers to the Harding Flash and Pattern Analyser—which was developed on the findings of Graham Harding, a professor at Aston University. The Harding Test was the first widely used tool to perform a PSE analysis in the early 90’s.
Over time,the term “Harding test” became the shorthand across the industry, and now several tools can now perform equivalent testing which meet UK Broadcast Specification.
Whether you’re submitting to the BBC, Channel 4, ITV, Sky, Clearcast, AdStream or a streaming service with UK delivery requirements, proof of a passed PSE test is often a mandatory part of delivery documentation.
In fact, broadcasters may outright reject your file if it fails. That means:
Redeliveries 🫣
Lost time ⏱️
Extra costs for last-minute VFX clean-up 💰
Not-so-happy clients 😐
Not ideal, right?
What Causes PSE Test Failures?
PSE test failures are usually caused by:
White or bright strobe effects (concert footage, flash transitions)
Quick scene cuts or intense jump edits
Rapid camera flashes in red carpet or paparazzi-style scenes
Animated graphics with fast flicker or contrasting stripes
Heavy glitch or VHS-style FX with chromatic separation
Sometimes the issues are obvious. But often, editors don’t even notice them until a QC test flags them up—and by then, you’re on deadline.
Why It Still Matters in 2025
While PSE testing has been around for years, it’s more relevant than ever:
More content is being delivered to multiple platforms—and many now adopt the same QC standards as traditional broadcasters.
Social responsibility is increasing—studios are more aware of accessibility and viewer safety.
Automation in QC is growing—which means your file is almost certainly being scanned before it airs.
Even if your broadcaster doesn’t require it, failing a PSE test could risk viewer complaints or a platform pulling your content!
With new AI editing tools and glitch-style FX everywhere, PSE compliance is becoming harder to eyeball and easier to miss—especially in fast-turnaround workflows.
So How Can You Stay Compliant?
That’s exactly why we built QC Kitchen.
Our automated QC tool carries out PSE testing to ITU 1702 (in SDR) and ITU 1702-3 (in HDR - coming soon) from just £5 per test. Upload your file and within minutes, you’ll know:
If it passed ✅
If not, where the flashing occurred 🚨
Frame-accurate breakdown of the problem areas 👍
It’s fast, accurate, and built for creative professionals who need peace of mind without renting a full on post house!
TL;DR – Key Takeaways
PSE testing checks your video for flashes and patterns that may trigger seizures in viewers with photosensitive epilepsy.
Harding Test is the colloquial term for this check, and is often required by broadcasters.
In 2025, with multi-platform delivery and tighter accessibility standards, automated PSE checks are a must-have.
PixelPantry’s QC Kitchen makes it simple - from just £5, upload your file and we’ll do the rest.
🎬 Want to run a PSE check on your next project?
Try QC Kitchen free and deliver with confidence.