What this opens on
Nothing added, nothing spoiled — and the page measures it instead of saying it.
The Faithful panel at 2×. The stage opens split against the original pixels, and under the 1:1 strip a line reads the overshoot of the patch you are looking at: how far any output pixel steps outside the range of the source pixels it came from.
| Setting | Effect at an edge | Why it is off or on |
|---|---|---|
| Mitchell | slightly softer, a small rim (7 levels) | on — the kernel with the least ringing |
| Lanczos 3 | sharper, a clear rim (25 levels) | off — measurable overshoot beside edges |
| Detail | steeper edges | 0 — sharpening is a change, however guarded |
| Clean-up | smoother flats | off — it removes texture with the noise |
| Halo guard | holds pixels in range | on — the safety net |
Where this falls down
- Bigger is softer.The same detail spread over more pixels looks softer at 1:1. That is the cost of enlarging, and no recipe removes it.
- It keeps the source's faults.JPEG blocks and noise are enlarged faithfully too. For a rough source, the low-resolution route cleans first.
Questions people ask
- Can any enlarger really avoid losing quality?
- It can avoid spoiling what is there: no ringing rims, no smoothed-away texture, no invented detail. It cannot add detail the file does not have, so a bigger picture always has less recorded detail per pixel. This page is the recipe that does the least harm, and it measures the harm rather than promising none.
- Why Mitchell and not Lanczos?
- Lanczos is sharper but its negative lobes draw a light or dark rim beside hard edges. Mitchell trades a little sharpness for a much smaller rim: on a near-black to near-white edge enlarged 4× in this engine's test suite, Lanczos overshoots by 25 levels and Mitchell by 7. The readout under the 1:1 strip shows the overshoot on the patch you are looking at, so you can switch methods and compare.
- What does 'max overshoot 1.6 levels' mean?
- For every output pixel in the 1:1 patch, the readout takes the four source pixels it was made from and measures how far the output sits outside their range, in 8-bit levels (0–255). Two levels or fewer is invisible; a visible rim is tens of levels beside an edge.
- Is a model ever used here?
- Not unless you add one in Enhance. A trained model invents detail, which is the opposite of this page's promise; the recipe starts with it off.
Better fit?
- Double the sizeThe factor with the least to apologise for. Opens at 2× on a sharp source.
- Enlarge a PNGTransparency-first: premultiplied resampling with no dark fringe, edge-guided for logos, PNG or WebP out.
- Increase image qualityClean-up first, guarded detail, an optional on-device model, and a same-size option. Judged at 1:1.
- What enlarging can and cannot get backWorked through at 2×, 4× and 8×, with the part that is a guess named as one.
