Contrast Card Generator

See what your baby sees: simulating infant acuity in the preview

The generator can blur a preview to approximate what a young baby actually sees at the chosen distance — a quick, honest reminder of why the cards are so bold and so big.

Mixed evidenceUpdated Aug 2, 2026For parents, general

Combines established science with practitioner guidance and our design opinion.

In one line

The generator can blur a preview to approximate what a young baby actually sees at the chosen distance — a quick, honest reminder of why the cards are so bold and so big.

Key points

  • A newborn’s world is not a small, sharp picture — it’s a low-detail, low-contrast one. At ~20/400, only bold, large light/dark forms come through.
  • The “acuity preview” takes the card as it will print and blurs it by the amount the viewer’s acuity implies at the print distance, so you can compare the crisp print with the softened version side by side.
  • It makes the design rules visible: fine detail simply disappears at low acuity, which is exactly why we strip it (see Turning a family photo into a high-contrast card) and size features well above the acuity limit (see How big should it be? A plain-language guide to sizing a contrast card).
  • It’s an illustration, not optics — a single-parameter blur, clearly labelled as a rough simulation, not a clinical rendering.

The evidence

  • [established science] Infant grating acuity is roughly 20/400 (~1 cpd) at birth, improving through the first months (AAO; PMC “Development of Visual Acuity and Contrast Sensitivity”; infant visual development §1).
  • [established science] In early infancy contrast sensitivity is the limiting factor as much as acuity — faint, fine detail isn’t just blurry, it can be undetectable (infant visual development §2). Our blur model captures the acuity side; the real loss of faint detail is, if anything, greater.
  • [our design opinion] How we turn the acuity limit into a blur radius (the finest resolvable bar at the distance, scaled into the preview — see viewing distance & sizing) is a deliberate, transparent approximation for education, not a measurement of any child.

Practical takeaways

  • Change the viewing distance and watch the simulated view soften — the same card is far less legible from across the room than up close.
  • If the blurred preview still reads clearly, you’ve got a bold, well-sized card. If it turns to mush, simplify harder or increase the size (or tile it larger).
  • Use it to set expectations: even a beautiful photo becomes a bold shape to a young baby — and that’s the point.
  • Use it to choose between patterns. The simulated view now sits next to the numbers for every design, so you can switch family and watch what survives. It is a fast way to feel something the numbers only state: at a nursery-ceiling distance a many-ringed bullseye collapses into a grey disc, while the same bullseye with a few thick rings still reads as rings. Fewer, bigger elements is not a stylistic preference — it is what is left after the blur (How big should it be? A plain-language guide to sizing a contrast card).

What changed (2026-08-02). The simulation used to appear only when you uploaded a photo. It now runs on every card — generated patterns and multi-sheet posters included — and updates live as you drag any control, because the thing worth comparing is usually the design decision you are making right now.

Caveats & disclaimer

This is a rough visual illustration of population-level acuity trends, not a test or diagnosis of any individual child’s vision, and it models acuity only (not the full loss of contrast sensitivity). Individual variation is large. Not medical advice; for any vision concern, see an eye-care professional.