How to permanently redact handwritten signatures
- Step 1Open the image with the signature — Drop a raster image (PNG, JPG, GIF, WebP, or BMP) onto the tool. If your signature is in a PDF, first export the page to an image — the picker uses the browser's
<img>decoder and will not render a.pdffile. The Signature Burner is a single-file tool: drop one document at a time. - Step 2Wait for the preview to render — The picker draws your image into a preview canvas capped at 640px wide (scaled down only — never up). The caption under it shows the true source dimensions, e.g.
source 2480×3508, so you know the full resolution the burn will run at. - Step 3Drag a rectangle over the signature — Press and drag across the signature, initials, or note. A translucent red box tracks the drag. The live readout shows the region in source pixels:
Region: 612×140 @ (1180, 2890). The rectangle is captured asx,y(top-left corner) andw,h(width, height). - Step 4Fine-tune with the numeric inputs (optional) — Below the preview are four number fields — X, Y, Width, Height — pre-filled from your drag. Type exact values to nudge the box pixel-by-pixel, e.g. widen
wby 20px to be sure you have caught a descender on the signature. Editing a field re-paints the red overlay so you can confirm coverage. - Step 5Burn the region — Run the tool. The processor fills your rectangle with solid
#000on the canvas and re-encodes the entire image as PNG. The burn only applies when bothwandhare greater than zero — a zero-area box is a no-op (the image is just re-encoded as PNG with nothing redacted). - Step 6Download and verify — Download the result — it is named
<original>-burned.<ext>, keeping your input's extension even though the bytes are now PNG. Open it in a fresh viewer, zoom into the black box, and try select/copy to confirm there is no recoverable layer. For a second region, run the tool again on the downloaded file.
Burn-region options (the only controls this tool has)
The Signature Burner exposes exactly four numeric options, all in source-image pixels. There are no color, blur, pixelate, multi-region, or PDF-page controls — drawing on the preview just sets these four numbers, which you can also type by hand.
| Option | Meaning | Default | Set by |
|---|---|---|---|
x | Left edge of the burn rectangle, in source-image pixels | 0 | Drag start, or typed in the X field |
y | Top edge of the burn rectangle, in source-image pixels | 0 | Drag start, or typed in the Y field |
w | Rectangle width in pixels. Burn applies only when w > 0 | 0 | Drag distance, or typed in the Width field |
h | Rectangle height in pixels. Burn applies only when h > 0 | 0 | Drag distance, or typed in the Height field |
What goes in vs. what comes out
Behaviour verified against the burn step: the image is decoded, the rectangle is filled with #000, and the canvas is re-encoded as PNG every time — regardless of the input format.
| Aspect | Behaviour |
|---|---|
| Accepted input | Any raster the browser <img> decoder reads: PNG, JPG, GIF, WebP, BMP. Animated GIF burns the first frame only. |
| PDF input | Not supported — fails to decode as an image. Export the PDF page to an image first, or use /pdf-tools/pdf-pii-redactor for the text layer. |
| Output format | Always PNG. The canvas is re-encoded with toBlob(..., 'image/png'), so a JPG in becomes PNG bytes out. |
| Output filename | <name>-burned.<original-ext> — the extension is unchanged, so a .jpg file holds PNG bytes. Rename to .png if a downstream tool is strict about extensions. |
| Redaction color | Solid black #000, opaque, no transparency or pattern. Not configurable. |
| Regions per run | One rectangle. Run again on the output for a second region. |
| Resolution | Burn runs at full source resolution; the 640px preview is for drawing only. |
Where it runs and what it costs
Signature Burner is browser-only (Canvas) and gated at the Pro tier. File-size caps are the per-tier security-family limits; the tool processes one file per run.
| Tier | Can run? | Max file size | Files per run |
|---|---|---|---|
| Free | No — this tool requires Pro | — | — |
| Pro | Yes | 100 MB | 1 |
| Pro-media | Yes | 500 MB | 1 (tool is single-file) |
| Developer | Yes | 2 GB | 1 (tool is single-file) |
Cookbook
Real redaction workflows for discovery and production teams. Coordinates and dimensions are illustrative but use the tool's actual x/y/w/h model and its real image-in / PNG-out behaviour.
Burn a signature off a scanned signature page
The classic discovery task: a notarized signature block on the last page of a scanned PDF that has already been split into per-page PNGs. You draw over the signature; the burn fills it solid black at full scan resolution.
Input: contract-page-12.png (2480×3508, 300dpi scan) Drag over the signature block → Region readout: 980×220 @ (1140, 3010) Options captured: x=1140 y=3010 w=980 h=220 Burn → solid #000 fills that rectangle, whole image re-encoded as PNG. Output: contract-page-12-burned.png • signature pixels overwritten — nothing under the box • every other pixel redrawn unchanged
Redact two signatures on the same page (run twice)
The tool burns one rectangle per run. For a page with both an employee and a witness signature, burn the first, download, then drop the burned file back in and burn the second. Each pass re-encodes to PNG; redacting an already-PNG file is lossless for the untouched pixels.
Pass 1: input: affidavit.jpg region: w=640 h=160 @ (300, 1850) # employee sig output: affidavit-burned.jpg (PNG bytes inside .jpg) Pass 2: input: affidavit-burned.jpg (the pass-1 output) region: w=580 h=150 @ (300, 2240) # witness sig output: affidavit-burned-burned.jpg Rename final file → affidavit-redacted.png
Fine-tune coverage with the numeric inputs
A fast drag often clips the tail of a flamboyant signature. Instead of redrawing, type into the Width/Height fields to extend the box. The red overlay repaints so you can confirm the descender is covered before burning.
After drag: x=1180 y=2890 w=600 h=120
Observed: the 'g' descender pokes out the bottom edge
Edit fields: h=120 → h=150 (extend down 30px)
w=600 → w=640 (catch the loop on the right)
New overlay confirms full coverage → burn.PDF page → image → burn (the correct PDF workflow)
Because the burner cannot decode a PDF directly, flatten the page to an image first. This destroys the searchable text layer in the process, which for a signature page is usually what you want anyway.
1. Export PDF page to image (any PDF viewer: 'Export as PNG')
deposition-exhibit-A.pdf → exhibit-A-p1.png
2. Drop exhibit-A-p1.png into Signature Burner
3. Burn the signature region
4. Output: exhibit-A-p1-burned.png
Note: this raster page has NO selectable text. If you need
to redact text in a born-digital PDF AND keep other text
searchable, use /pdf-tools/pdf-pii-redactor instead.Confirm the redaction is unrecoverable
The reason to use a burner instead of a viewer's black box: verify there is genuinely nothing underneath. Open the output cold and probe it.
Verification checklist on <file>-burned.png:
• Zoom 800% into the black box → uniform #000, no ghost ink
• Try select/copy over the box → nothing selectable (it's pixels)
• Inspect the file: it's a single flat PNG raster, no layers,
no annotation objects, no /XObject form to delete
• Compare byte size to original — re-encoded, not appendedEdge cases and what actually happens
You drop a PDF onto the tool
Fails to loadThe region picker and the burn step both decode the input with the browser's <img> element, which cannot render a PDF. You will get a 'Failed to load image' error and no preview. Export the PDF page to PNG/JPG first, or for text-layer redaction in a born-digital PDF use /pdf-tools/pdf-pii-redactor.
Output is PNG even though you dropped a JPG
By designThe canvas is always re-encoded with toBlob(..., 'image/png'), so every output is PNG bytes regardless of input format. Re-encoding is what guarantees the burned pixels are baked in. The catch: the file is named <name>-burned.jpg, keeping the original extension, so the bytes are PNG inside a .jpg name. Rename to .png if a strict downstream tool complains.
Zero-area rectangle (you clicked but didn't drag)
No-opThe burn only fills when both w > 0 and h > 0. A click with no drag leaves w/h at 0, so nothing is redacted — but the image is still re-encoded to PNG and downloaded. If your output looks identical, check the region readout shows a non-zero w×h before burning.
Animated GIF with a signature on a later frame
First frame onlyThe <img> decoder hands the canvas the first frame, so only frame one is drawn and burned; the output is a single static PNG. If the signature is on a later frame, extract that frame to a still image first. This is rarely an issue for documents but matters for screen-recording GIFs.
Free-tier user tries to run it
Tier requiredSignature Burner is gated at the Pro tier (minTier pro). Free accounts cannot run it. Pro allows up to 100 MB per file; Pro-media 500 MB; Developer 2 GB. The tool is single-file regardless of tier — there is no batch mode.
Preview looks small but your scan is huge
ExpectedThe preview is capped at 640px wide and only ever scaled down. The burn does NOT use preview coordinates — every drag is converted to source-image pixels (the caption shows the true source W×H). So a box drawn on the 640px preview lands exactly on the right region of a 4000px scan.
Signature spills outside the rectangle after burning
Re-runBurn covers only the rectangle you set. If a loop or descender pokes out, the visible ink is still in the output. Drop the burned file back in and burn a second box over the remainder, or widen w/h before the first burn. There is no eraser or undo within a single run.
Black box added in a PDF viewer instead of this tool
Reversible — avoidA rectangle drawn as an annotation in a PDF viewer is a separate layer; deleting the annotation or running pdftotext exposes the ink. That is the exact failure this tool exists to prevent. Burning re-encodes a flat raster with no separable layer, annotation object, or form XObject to remove.
CMYK or exotic-profile JPG
Depends on browserThe tool relies on the browser's native image decoder. Standard RGB PNG/JPG always work; a CMYK JPEG or an unusual ICC profile may fail to decode in some browsers, surfacing as 'Failed to load image'. Re-save it as a standard sRGB PNG/JPG and retry.
Re-encoding changes the file's byte size
ExpectedBecause output is always a fresh PNG, a JPG input (lossy, small) often comes out larger as a lossless PNG. The untouched pixels are visually identical; the size difference is just PNG vs JPG encoding, not a sign of data loss or hidden data.
Frequently asked questions
Is the redaction actually irreversible?
Yes. The tool fills your rectangle with solid #000 on a canvas and re-encodes the whole image as a new PNG. The output contains only the pixels the canvas painted — the original ink under the box was never written into the result. There is no annotation, layer, or form object to delete, and no recoverable byte stream. This is the difference between burning and the black-box annotation a PDF viewer adds on top.
Can I redact a signature directly in a PDF?
Not in this tool — it decodes input with the browser's <img> element, which cannot render a PDF, so dropping a .pdf throws 'Failed to load image'. Two correct paths: export the PDF page to a PNG/JPG and burn that, or for redacting text in a born-digital PDF while keeping the rest searchable, use /pdf-tools/pdf-pii-redactor. To strip hidden PDF metadata, see /pdf-tools/pdf-metadata-scrubber.
Why is my output a PNG when I uploaded a JPG?
The canvas is always re-encoded as PNG (toBlob(..., 'image/png')) — that re-encode is what bakes the black box permanently into the pixels. So a JPG in becomes PNG out. The downloaded file keeps the original extension in its name (<name>-burned.jpg), so it is PNG bytes inside a .jpg filename; rename it to .png if a strict downstream tool needs a matching extension.
Can I burn more than one region at once?
No — the tool takes a single rectangle (x, y, w, h) per run. For multiple signatures on a page, burn the first, download the result, drop it back in, and burn the next. Each pass re-encodes to PNG, and the untouched pixels stay visually identical, so chaining passes is safe.
Does the file get uploaded anywhere?
No. Signature Burner is browser-only — it runs entirely on the HTML Canvas in your tab. The document never reaches a server, which is what makes it appropriate for privileged, sealed, or pre-discovery material. An audit-log entry is emitted locally to record that a redaction was performed.
Can I change the redaction color or use a pixelate/blur instead?
No. The fill is solid opaque black (#000) and is not configurable — there is no color picker, blur, or pixelate option in this tool. For pixelating faces in images, see /video-tools/face-pixelate. For signatures, solid black is the standard discovery/FOIA convention and is what this tool produces.
I drew the box on a small preview — will it line up on my full-res scan?
Yes. The preview is capped at 640px wide for drawing convenience, but every coordinate is converted to source-image pixels before the burn. The readout under the preview shows both your region (612×140 @ (1180, 2890)) and the true source size (source 2480×3508), so a box drawn on the preview lands exactly on the right region at full resolution.
What image formats can I drop in?
Anything the browser's image decoder reads: PNG, JPG, GIF, WebP, and BMP. Animated GIFs burn the first frame only. PDFs are not supported — convert the page to an image first. CMYK JPEGs or files with unusual color profiles may fail to decode in some browsers; re-save as standard sRGB PNG/JPG if you hit 'Failed to load image'.
Why does nothing get redacted when I run it?
The burn only applies when both width and height are greater than zero. If you clicked without dragging, w and h stay at 0 and the rectangle is a no-op — the image is just re-encoded to PNG with nothing covered. Check the region readout shows a non-zero w×h before burning, or type values into the Width/Height fields.
What tier do I need and how big can the file be?
The tool requires the Pro tier (Free cannot run it). File-size caps follow the security family: Pro 100 MB, Pro-media 500 MB, Developer 2 GB per file. It is single-file regardless of tier — drop one image per run; there is no batch mode.
Is burning admissible / sufficient for legal redaction?
Pixel-level burning produces a flat raster with no recoverable layer, which is exactly what redaction standards for discovery and FOIA require — far stronger than a deletable black-box annotation. That said, requirements vary by jurisdiction and matter; confirm your specific production protocol with your legal team. Also remember to redact PDF metadata separately with /pdf-tools/pdf-metadata-scrubber and check images for hidden EXIF with /image-tools/exif-scrubber.
How do I verify there is really nothing under the black box?
Open the -burned.png output cold in a fresh viewer. Zoom to 800% into the box — it should be uniform #000 with no ghost ink. Try to select/copy over it — nothing is selectable because it is pixels, not text or an annotation. The file is a single flat PNG with no layers or annotation objects to delete. For a deeper integrity check across files, see /security-tools/multi-hash-fingerprinter or /security-tools/entropy-analyzer.
Privacy first
Every JAD Security operation runs entirely in your browser. Files, passwords, and PGP private keys never leave your device — verified by zero outbound network requests during processing.