Squint test
Designers have long checked layouts by squinting at them. Blurring your vision removes the words and leaves only size, darkness and colour, which is roughly what an audience registers in the first second a slide appears. Whatever still stands out when blurred is where the eye goes first.
That makes the squint test a quick check of visual hierarchy. On a good slide the element that survives the blur is the message: the headline that states the finding, or the one highlighted bar that proves it. On a weak slide it is a logo, a decorative shape, or nothing at all, because every element has the same weight.
Below are three designs of the same slide with the same data. Move the blur slider and, for each design, decide where your eye lands before opening the explanation. Then try the test on one of your own slides: export it as an image and load it. The file is read in your browser and never leaves your device. If the blurred version points at the wrong thing, make the message bigger or darker and quiet everything else, then test again.
Three designs, one blur slider
Three designs of the same slide. Drag the blur slider up and ask one question for each: which element does the eye land on first? If the answer is not the message, the design is working against the speaker.
Design A · Everything equal
Where does the eye land?
Nowhere in particular. Blurred, the slide turns into an even grey texture: the title, the paragraph and the chart all have the same weight and tone, so nothing leads. The eye drifts to the biggest block, the paragraph, which is the least useful part.
Design B · Loud decoration
Where does the eye land?
The orange shape and the logo. They are the largest, brightest and most saturated things on the slide, so they win even at full blur. The actual finding, "churn fell to 4%", is small and low in the corner, and disappears first.
Design C · Clear hierarchy
Where does the eye land?
The headline, then the purple bar. The message is the largest, darkest element, and the only coloured bar marks the month it talks about. Blurred, you still see a big dark line of text above a row of bars with one standing out, which is the whole story.
At 8 px blur, which slide still tells you its point?
Your turn
Test one of your own slides. Export it as an image, then choose the file or paste it here. The image stays in this browser tab; nothing is uploaded. Without this tool the same test works by stepping two metres back from the screen or half-closing your eyes.
Questions
What is the squint test?
An old designers' habit: look at a layout with half-closed eyes. Detail disappears and only contrast, size and position remain, which is roughly what an audience registers in the first second. The blur slider does the same thing on screen, so the result does not depend on how well anyone squints.
How much blur should be used?
Enough that the words can no longer be read. On this tool that happens at around 8 pixels of blur; from there on, whatever still stands out does so because of its size, weight or colour, not because of what it says. That is the visual hierarchy of the slide.
Is an uploaded slide sent anywhere?
No. The image is read by the browser itself and shown on the page; it is never uploaded to a server and disappears when the page is closed or reloaded. Screenshots of confidential decks can be tested safely.
What should survive the blur?
One clear lead element, usually the headline or the single highlighted data point, followed by a visible second level. If everything blurs into an even grey, nothing leads and the audience has to read every line to find the point. If three things shout equally, they cancel each other out.