Vector or Raster? Choosing the Right File Format for Surface Pattern Design

Ask three pattern designers which software they use and you will get three answers, usually with strong opinions attached. Ask which file format they save in and the conversation goes quieter, because the honest answer is: it depends on the pattern. Vector and raster files behave differently the moment you scale, recolour or hand work to a client, and choosing well at the start saves hours of redrawing later.

What vector and raster files actually are

A vector file describes artwork as maths — anchor points, curves, fills. Nothing is drawn until the software opens the file and follows the instructions. Because those instructions carry no fixed size, a vector motif can travel from a phone case to a wall mural with its edges still crisp. You will meet vectors as .ai, .eps, .svg and vector-based .pdf files.

A raster file is a grid of pixels, each one holding a colour value. What you see is fixed at the resolution you built it in, which is how .psd, .tif, .png and .jpg files behave. Scale a raster motif up by 200 per cent and the software has to invent pixels that were never there: edges soften, fine texture smears, and any hand-painted character starts to look blurry.

A useful shorthand: a vector is a set of instructions for drawing a shape; a raster is a photograph of the finished drawing.

A side-by-side comparison

• Scaling. Vector holds at any size. Raster is locked to its pixel dimensions, so plan for the largest size you might ever need before you start painting.
• File size. A vector repeat of a hundred simple shapes might be a few hundred kilobytes. The same design painted in raster at 300 dpi across a wide fabric repeat can run to hundreds of megabytes.
• Editing. Vector lets you nudge a single petal, adjust its curve or swap a colour across the whole tile in one pass. Raster editing is per-pixel work: precise, but slower for structural changes.
• Texture. Raster captures the grain of a dry brush, the bloom of watercolour and the tooth of paper. Vector edges are clean by nature, so texture has to be added, layered or simulated.
• Recolouring. Global swatches and recolour tools make colourways quick in vector. In raster you rely on adjustment layers, layer styles and careful selection work.
• Handover. Printers and manufacturers generally want vector for clean line work and spot-colour jobs, and high-resolution raster for painted or photographic artwork. Ask before you build the file, not after.

When a vector workflow earns its keep

Some pattern categories are simply quicker in vector: geometrics, stripes, dots, chevrons, tessellations, flat florals, lettering-led prints and anything heading for a children's range. Anything that needs to tile perfectly with clean seams also behaves better when the repeat is built from paths you can measure and align.

Vector is also the friendlier format for licensing. When an art director asks to see a design in navy and blush, or wants the motif enlarged for a bedding scale, a vector file delivers both in minutes. Screen-printing separations, cut files for vinyl, and technical repeats with precise measurements all sit more comfortably in vector too.

Two habits worth keeping: build the tile itself rather than eyeballing a grid of copies, and name your swatches and layers as you go. Future you, opening the file in six months, will be grateful.

When raster is the right call

If the charm of a design lives in its texture, stay in raster. Watercolour washes, gouache, soft pastel, pencil shading, ink bleeds, scanned fabric, collage and hand-printed marks all lose something when they are forced into clean paths. Auto-tracing painted artwork rarely ends well: soft edges become lumpy contours, and you inherit thousands of anchor points that are miserable to edit.

The working rule is to paint at the resolution you will print at, at the size of your largest repeat. For printed textiles and paper goods, 300 dpi at final dimensions is the usual benchmark — confirm it with whoever is producing the work. A 60 cm repeat at 300 dpi is roughly 7,000 pixels across, which is large but manageable if you keep motifs on separate layers and work from a single master file instead of duplicating it for every experiment.

The hybrid route, which is what most work actually looks like

Plenty of commercial patterns are a vector tile holding raster elements, or a high-resolution raster tile with vector lettering dropped in. Both approaches work, provided the raster parts are built at a resolution that covers the largest intended use. A painted motif scaled down inside a repeat is fine; scaled up, it is not.

The one rule for hybrids: always keep a layered master. Flattened files are for delivery, never for editing. If a client returns asking for a colourway change on painted artwork, a grouped, layered master saves the job — and possibly the deadline.

Export, resolution and colour

Resolution

Match resolution to final use rather than habit. Print work generally wants 300 dpi at 100 per cent of the intended size; screen-only mock-ups are fine at a fraction of that. Upscaling a finished raster tile will not rescue an undersized file — resampling adds pixels, not detail. If you need it bigger, rebuild or repaint it.

Colour

Keep a working RGB master for flexibility and prepare output versions to the brief. Print work often needs CMYK or a specified spot colour, while textile production may ask for a limited colour count or Pantone references. If you are unsure what a mill, printer or client requires, ask before you save the final file; converting colour after the fact can shift everything you carefully matched.

A simple delivery checklist

1. Layered working master: .ai or .psd, kept for yourself.
2. Vector delivery: .eps, .pdf or .svg.
3. Raster delivery: .tif or .psd at the agreed resolution, uncompressed.
4. Preview file: .jpg or .png at a sensible size, watermarked if it is going out for review.

Put the repeat dimensions somewhere obvious. A file named wildflower_tile_30cm_300dpi_v3 tells a client far more than final_final2 ever will.

A simple way to decide

Three questions usually settle it. Does the artwork need to scale well beyond its original size? If yes, vector. Does the appeal sit in texture rather than shape? If yes, raster, painted at print resolution. Will colourways or structural edits be requested later? If yes, keep a vector master or a layered raster one, and never work from the flattened export.

When a brief is genuinely both — a painted floral that also needs to scale onto a large upholstery repeat, say — build in whichever half is harder to fake, then bring the other in. Paint the motifs in raster, cut them out, and place them inside a vector tile that you can resize and recolour without touching the artwork.

Format choices are invisible in the finished pattern, yet they decide how painful the next revision is. Save the layered master, name files so a stranger can read them, and note the intended repeat size before you send anything out the door.

Photo: Ron Lach / Pexels