Overview
Introduction
This tool improves the visual quality of a blurry or low-resolution stamp scan entirely in your browser, by composing two real pixel operations: sharpening and upscaling.
It's an honest enhancement tool, not an AI upscaler — it can make existing edges crisper and the image physically larger, but it can't add detail that was never captured in the source.
What Is Low-quality Stamp Fixer?
A client-side image-enhancement tool that first applies an unsharp-mask-style 3x3 convolution to boost local edge contrast, then optionally resizes the result larger using nearest-neighbor resampling.
Both steps reuse this category's existing sharpen and upscale lib functions rather than introducing new pixel math.
How Low-quality Stamp Fixer Works
The sharpen pass boosts each pixel relative to its four orthogonal neighbors using a 'plus' convolution kernel, amplifying contrast at edges so faint or slightly blurred stamp lines read more clearly.
If an upscale percentage above 100 is requested, the already-sharpened image is then resized larger with nearest-neighbor sampling, which enlarges without introducing new blur.
When To Use Low-quality Stamp Fixer
Use it on a stamp photo or scan that came out slightly soft or was captured at low resolution, before using it in a document or design.
It's also useful as a final cleanup pass after other stamp edits, if resizing or recoloring left edges looking a bit soft.
Often used alongside Stamp Resizer, Black and White Stamp Creator and Rubber Stamp to Digital Stamp Converter.
Features
Advantages
- Runs entirely client-side; the uploaded stamp is never sent to a server.
- Composes two already-tested pixel operations instead of introducing new, unverified math.
- Sharpening happens before upscaling, which avoids amplifying upscale blockiness.
Limitations
- Cannot recover detail that was never captured in the original photo or scan; it's a real contrast/edge enhancement, not AI super-resolution.
- Aggressive sharpening on a noisy or JPEG-artifacted source can introduce visible haloing around edges.
Examples
Best Practices & Notes
Best Practices
- Start with a moderate sharpen amount (80-120) and increase gradually while watching for haloing artifacts.
- Only upscale as much as you actually need; heavier upscaling makes nearest-neighbor blockiness more visible.
Developer Notes
This lib file composes two already-shipped, independently tested pure functions — sharpenPng and upscalePng — rather than writing new convolution or resampling math; sharpening always runs before the optional upscale step so the kernel samples the original pixel density.
Low-quality Stamp Fixer Use Cases
- Cleaning up a slightly blurry phone photo of a physical stamp
- Enlarging a small scanned stamp for use in a bigger document layout
- Sharpening edges that softened after other pixel-editing steps
Common Mistakes
- Expecting the tool to add detail that simply wasn't captured in the original image.
- Over-sharpening a noisy scan, which amplifies grain and JPEG artifacts along with real edges.
Tips
- If the result looks too harsh, lower the sharpen amount rather than the upscale percentage.
- For a very small source image, consider rescanning at a higher resolution instead of relying solely on upscaling.