Testing Two Nursery Plates at A3: Print Resolution Measured

Print resolution is the wrong first question for a nursery chart at A3. Hear the desk out. Two plates from the studio catalogue went through the same A3 test rig this month — El Abecedario, the Español alphabet in soft pastels, and One to Ten, the counting chart with dot groupings. Both are original vector art, which means the pixels-per-inch figure at 297×420mm is a function of export settings, not of the source file. What the test actually measured, and what routed each plate to its recommendation, was ink coverage on pastel fills and line weight legibility from a standing distance of three feet.

Question 1: Is the source file vector or raster?

This is the first fork, and it decides most of what follows. A vector file has no native resolution. It carries mathematical instructions — a curve here, a fill of this hex value there — and the rasteriser at the print shop turns those instructions into dots at whatever DPI the printer is set to. A raster file arrives with its resolution baked in. If a raster nursery chart was drawn at 150 DPI for a 210×297mm A4, printing it at 297×420mm A3 will interpolate every pixel and the letter edges will fuzz.

Both charts in this test — El Abecedario and One to Ten — are original vector art. Every letterform in the Español alphabet is a curve. Every counting dot on the numbers plate is a filled circle described by centre point and radius. Exported at 300 DPI, an A3 sheet is 3508×4961 pixels. Exported at 600 DPI, the same sheet is 7016×9921 pixels. The vector source produces both without any loss of edge quality. That is the whole point of drawing charts for print in vector to begin with.

If Yes

If the source is vector, the print resolution question collapses into an export decision. The studio's A3 export standard is 300 DPI for pastel-fill charts (El Abecedario, One to Ten) and 400 DPI for charts with fine outline detail (Dinosaurs to Scale, where the silhouettes need crisp edges next to the human figure). Both settings produce sharp output at three feet. Going above 400 DPI at A3 delivers no visible improvement to a standing child — the eye cannot resolve the difference at that reading distance — but it does bloat the file, slow the RIP at the print shop, and occasionally trigger colour drift on lower-end pigment printers that overheat mid-sheet.

The recommendation for both plates in this test was 300 DPI. El Abecedario passed the A3 line-weight audit at that setting with no re-export needed. One to Ten passed at 300 DPI as well; the dot fills held their pastel tone without banding on both the matte and satin paper samples we ran through the rig.

If No

If the source is raster, ask what native resolution it was drawn at. Anything below 300 DPI at the finished print size is going to soften. A chart authored at 300 DPI for A4 will land at roughly 212 DPI when stretched to A3 — visible fuzz on letterforms, visible pixel steps on any diagonal line, and a general loss of the crispness that separates a nursery print from a home inkjet copy. The honest answer in this case is to redraw or to print smaller. Upscaling filters in modern print software help at the margins but do not manufacture detail that was never captured. Neither chart in this test was raster, so this branch is closed for the plates under review.

Question 2: Is A3 the wall's real reading distance?

A3 is 297×420mm — roughly 11.7×16.5 inches. It is a common nursery chart size for a specific reason: it fills a meaningful section of wall above a changing table or a low bookshelf without dominating the room, and it reads clearly from the middle of a small nursery. But the size question is not decorative. It is functional. A chart that a two-year-old will stand three feet from wants different line weights and different letter heights than a chart that an adult will glance at from six feet away across a sofa.

The A3 test rig at the studio sits a print on a plain white wall at 1.2 metres from the floor, then measures legibility from 90cm — the standing eye level of a typical three-year-old. That is the working reading distance for a nursery wall chart. It is not a poster over a fireplace. It is a chart at toddler eye height, read by a toddler.

If Yes

If the wall's real reading distance is three feet or under, A3 is correct and the two plates in this test both cleared the legibility bar comfortably. El Abecedario's letter cap heights at A3 measure roughly 32mm, which the desk cross-checked against the 25mm minimum we use for nursery alphabets read at three feet — well inside the safe range. The friendly companion word under each letter runs at roughly 12mm cap height, still readable at three feet by an adult reading aloud to the child, which is the actual use case for early alphabet exposure.

One to Ten at A3 places each numeral at roughly 60mm cap height with dot groupings sized at 18mm diameter. Both figures cleared the rig comfortably. A parent counting dots with a child at three feet can point at each individual dot without ambiguity, and the numeral itself is legible from across a small nursery.

If No

If the wall's real reading distance is six feet or more — the chart is going above a sofa in a shared family room, across a longer nursery, or on a stair landing — A3 starts to compress. The letter cap heights that are generous at three feet start to feel small at six. The desk's default for reading distances above five feet is to move to A2 (420×594mm), which roughly doubles the surface area and lifts every letterform and dot into comfortable legibility from further back. Both plates in this test are also stocked at A2 for this reason. Neither of them was drawn only for A3. The vector source handles the scale-up cleanly.

Question 3: Does the chart lead with color fields or line detail?

This is the fork that most print-resolution discussions skip, and it is the one that mattered most in this test. Two charts can share the same file format, the same DPI, and the same finished dimensions, and print differently because of how they distribute ink on the page. A pastel-fill chart lays down large flat areas of soft colour. A line-detail chart carries most of its visual information in thin strokes on a white ground. The pastel-fill chart is tested for ink coverage evenness. The line-detail chart is tested for stroke weight preservation.

If Yes

If the chart leads with colour fields, ink coverage is the real test. El Abecedario is a pastel-fill chart: each letter card is a soft-tinted block with a friendly companion illustration inside it. The A3 test looked at whether the pastel fills held their tone across the sheet without banding, and whether the two adjacent pastel cards read as distinct colours at three feet. Both checks passed. The desk's pastel palette is engineered with roughly 8-12% saturation and controlled hue spacing between adjacent cards, which means the printer never has to lay down heavy ink and the eye does not confuse neighbouring letters.

One to Ten also leads with colour fields — each numeral card is a soft pastel background with a set of contrast-toned dots on top. The A3 print showed the dot-to-background contrast held at three feet even in the paler cards (the palest yellow ground was the risk area, and it cleared). Ink coverage on both plates averaged in the safe range for pigment printers on 200gsm matte stock, with no over-inking artefacts on the darker cards.

If No

If the chart leads with line detail, stroke weight preservation is the real test. Dinosaurs to Scale sits in this category — its silhouettes need crisp outlines and its scale-bar tick marks are thin strokes that must survive the print pipeline. The A3 test for a line-detail chart looks at whether strokes below 0.5pt hold up without breaking, and whether hairline registration marks stay visible. Neither of the two plates in this test leads with line detail, so this branch closed for the current review. Both plates in the current test are colour-field charts. The next A3 test session will run Dinosaurs to Scale through the same rig for the line-detail branch.

If You Answered Everything: The A3 Recommendation Matrix

The three forks combine into an eight-row recommendation table. Each row is one answer combination. The recommendation cell states the concrete route for that combination — the actual next step, not a summary.

Q1: Vector?	Q2: 3ft reading?	Q3: Colour-field?	Recommendation
Yes	Yes	Yes	Print at A3, 300 DPI, matte or satin — this is the tested route for El Abecedario and One to Ten.
Yes	Yes	No	Print at A3, 400 DPI, matte only — reserve for line-detail plates like Dinosaurs to Scale.
Yes	No	Yes	Move to A2 at 300 DPI — the vector scales cleanly and reading distance justifies the larger sheet.
Yes	No	No	Move to A2 at 400 DPI — the safest route for line-detail charts on longer walls.
No	Yes	Yes	Redraw as vector before printing A3, or drop to A4 to keep native DPI intact.
No	Yes	No	Redraw as vector — raster line-detail at A3 will not hold stroke weight.
No	No	Yes	Redraw as vector — raster upscaled to A2 will visibly soften on flat colour edges.
No	No	No	Redraw as vector — this is the worst combination for a print outcome.

The pattern in the matrix is straightforward: if the source is vector, the decision routes cleanly on reading distance and chart type. If the source is raster, the recommendation collapses toward redraw regardless of the other two answers. That is not a purism; it is what the print outcomes show when you sit the sheets on a wall and stand a small human in front of them.

The two plates in this test — El Abecedario and One to Ten — sit on the top row of the matrix. Both are vector, both are correctly sized for a three-foot reading distance, and both lead with pastel colour fields. Both cleared A3 at 300 DPI. Neither needed a re-export. What the DPI figure did not tell us on its own was whether the pastel palette would hold its tone at that setting across an A3 sheet, or whether adjacent cards would read as distinct colours at three feet. Those were the questions the rig was actually asked to answer. The answers were yes and yes.

None of this tells you which of the two plates belongs above your changing table. That question is about hanging height, sightlines and what the child in the room is learning next, and it is not where a print-resolution test ends. The catalogue at /shop/ carries both plates at A3 and A2, and the desk's next test session moves to the line-detail branch of the matrix with the Dinosaurs to Scale plate on the same rig.

FAQ

What DPI should a nursery chart be printed at for A3?

For vector source files with pastel colour fields — the shape El Abecedario and One to Ten take — 300 DPI is the tested export setting for A3 and produced no visible softness at a three-foot reading distance. Line-detail charts benefit from 400 DPI to preserve thin stroke weights. Above 400 DPI at A3, the extra pixels do not resolve at toddler standing distance and mostly slow the print pipeline.

Why is vector source better than raster for a nursery print?

Vector art carries mathematical instructions rather than fixed pixels, so the same source file exports crisply at A5, A4, A3 or A2 without any interpolation softness. A raster file authored at 300 DPI for A4 falls to roughly 212 DPI when stretched to A3, which shows as fuzzy letter edges and visible pixel steps on diagonals. Every plate in the studio catalogue is drawn as vector for this reason.

Does A3 work for a chart hung above a sofa?

Probably not, if the sofa puts the reading distance at five or six feet. A3 letter and numeral heights are calibrated for a three-foot standing reader — a toddler at the wall. Above five feet, the desk's default is to move to A2, which roughly doubles the surface area and restores comfortable legibility. Both plates in this test are stocked at A2 for the longer-reading-distance case.

What is the reading distance a nursery chart is designed for?

The studio's rig assumes a three-year-old at roughly 90cm eye height, standing about 90cm from the wall — a working distance of three feet. This is not the same as an adult glancing at the chart from across a room. Letter cap heights, numeral sizes and dot diameters are all set against the three-foot figure, which is what actually happens when a small child uses the chart.

Which paper stock did the A3 test run on?

The test used 200gsm matte and satin stocks, both pigment-printed. El Abecedario and One to Ten cleared both. Matte is the desk's default recommendation for nursery walls because it kills reflection from ceiling lights and side windows, which matters when the chart is hung low and read from below. Satin is fine on a shaded wall but starts to catch glare in a room with strong overhead light.

Do the pastel colours hold their tone at A3?

Yes, on both plates tested. The studio's pastel palette runs at roughly 8-12% saturation with controlled hue spacing between adjacent cards, so the printer never lays down heavy ink and neighbouring cards remain distinct at three feet. The palest yellow ground on One to Ten was the risk area for dot-to-background contrast and it cleared the rig. No banding was observed across the flat fills on either sheet.

Should I go bigger than A3 for a nursery chart?

Only if the reading distance justifies it. A3 fits the standard nursery configuration of a chart above a changing table or low bookshelf, read by a standing toddler at three feet. If the chart is going on a longer wall — a stair landing, above a sofa in a shared family room, across a wider nursery — move to A2. Vector source handles the scale-up without any loss.