Cleaning up a low-resolution or JPEG logo before tracing

Tracing does not add resolution: a 200-pixel logo traced at any setting is still a 200-pixel design with guessed curves. What you can fix is noise — JPEG blocking, colour speckle, soft edges — by feeding the tracer a larger, cleaner source and a low colour count. png2svg.art runs a palette clean-up on every colour trace, so compression noise is folded into the real colours; a few minutes in an image editor beforehand does the rest.

Start by being realistic

A vector trace follows the boundary between colours in the pixels you give it. If the boundary is blurry, the trace is a guess; if a stroke is two pixels wide, the trace is a two-pixel-wide guess. No preset recovers detail that is not there. The honest question is not "which setting sharpens this?" but "do I have a bigger or cleaner version of this logo anywhere?" — an old print-ready file, an e-mail signature, the original designer's file. Any of those beats a thumbnail.

Bigger helps only up to a point: images over 2048 pixels on the long side are scaled down to 2048 pixels before tracing, so a source at that size already gives the tracer everything it will use.

What JPEG does to a logo

JPEG compresses 8×8-pixel blocks and discards fine colour detail. On photographs that is invisible; on a flat two-colour logo it produces ringing along every edge (halos of slightly wrong colour), block edges in flat areas and a spray of near-duplicate colours where there should be one. Traced naively, each of those near-duplicates can become its own ragged path.

A small, blocky JPEG of an owl logo enlarged; the same JPEG traced at 3 colours, clean; and at 12 colours, with halos and specks

Our owl logo reduced to 128 px and saved as a JPEG at quality 30 (left, enlarged to show its pixels). Traced at 3 colours, its true count, it comes back as 13 clean paths (middle). At 12 colours the compression noise returns as halos and specks: 11 colours, 59 paths (right).

The built-in clean-up

Every colour trace — the Standard, Cricut / Vinyl and Detailed artwork presets, with Smooth curves on or off, JPEG or already-flat PNG — goes through the same palette clean-up before anything is outlined. Only Line art / Stencil skips it, because it reduces the picture to black and white instead.

With Smooth curves on, small images are first enlarged smoothly, so the boundary between two colours can fall between the original pixels rather than on their grid.
The colours are chosen from "interior" pixels only — those inside flat areas, away from edges, where JPEG ringing lives. Colours that differ only by compression noise are merged; a small colour that is clearly different, such as a thin outline, is kept while the colour count allows.
Every pixel is snapped to one of the chosen colours. Pixels on an edge are decided between the two colours on either side, so a halo of in-between shades does not become a colour of its own.
Specks smaller than 4 pixels take the colour around them (Detailed artwork keeps smaller ones; Cricut / Vinyl adds its own, stronger cutting clean-up), so crumbs do not become shapes of their own.

On a very large, very noisy image the clean-up can run out of time; the tracer then reduces the colours in a simpler way. That is rare.

Preparation that helps

Upscale only if you will also clean up. The tracer already enlarges small images before choosing colour boundaries (step 1 above), so resizing a 300-pixel logo to 1200 pixels yourself adds no information of its own. It pays off when you then repair the enlarged image by hand — straighten an edge, fill a gap, remove a stray mark — at a size where that is easy.
Reduce the colours yourself. In an image editor, posterise or index the logo to its true colour count with no dithering. A two-colour logo saved as an indexed PNG with two colours traces almost perfectly.
Fill the background with one flat colour (or make it transparent) so background removal can take it out cleanly.
Crop tight. Border artefacts and stray marks near the edges confuse the background detection.
Save as PNG. Re-saving a JPEG as a JPEG adds another round of loss.

Settings for a noisy source

Standard preset, Smooth curves on, colours set to the true count. Lowering the colour count is the single most effective control on a noisy logo: with 3 colours, every ringing pixel has to be assigned to one of three real fills, which is exactly the clean-up you want.

If small text becomes unreadable, do not raise the colour count — that can let noise back in as extra shades. Instead, upscale the source or accept that text below roughly 10 pixels tall will need to be retyped with a font in a vector editor and placed over the trace.

What to check in the preview

The palette strip lists only your logo's colours (plus background).
With Layers set to By color, the path count equals the colour count: a clean three-colour logo is three paths. If the palette shows two near-identical shades of one colour, lower the count by one.
Zoom into the edges; a slight softness is normal after clean-up, but wobbling outlines mean the source is too small.