1 · Upload and crop
Upload or drag in a gel image, or start with the synthetic example. In Image / canvas, choose Crop and drag the region to keep. The project retains the original image.
FIGPAD LAB TOOLS
Gel image annotation
Crop a gel image, label its ladder and lanes, and highlight bands.
Images are processed in your browser, without server uploads.
Bring your gel image
Drop a PNG, JPG or WebP, up to 24 MB
How it works
How to Annotate Gel Images with FigPad
2 · Set lanes and marker
Create lanes in Gel / lanes. Select a rectangle, drag inside to move it, and use its edge handles to resize. Choose your actual marker product and lane, then verify the known band sizes.
3 · Align and annotate
Align every scale handle to a real marker band. Use the separate frame, arrow, and text tools beside the canvas, and edit styles in Annotations. Check all scale marks before exporting.
4 · Save and export
Export PNG or SVG at the top of the page. Save an editable JSON project to retain the image, lanes, and annotations, then reopen it later. Save before reloading or closing the page.
Gel Annotation FAQ
Which images are supported?
Use JPG, PNG, or WebP up to 24 MB, 32 megapixels, and 16000 pixels per side. Prefer clear original gel photographs over compressed screenshots.
How do I resize a lane?
In Gel / lanes, select the lane rectangle. Drag its left/right handles to change width, top/bottom handles to change height, or its interior to move. You can also enter exact coordinates and dimensions.
Are marker presets already calibrated?
No. Presets supply known sizes from manufacturer documentation. Match your actual reagent and align every mark to its real band. Red handles remain unaligned; initial positions are not calibration.
Does this infer molecular weights? Does it use credits?
This is a manual annotation tool. It does not detect bands or infer unknown molecular weights. Sign in to use it; annotating and saving projects are free, and exporting a PNG or SVG uses 1 credit per image, with re-exports of the same image free for 24 hours. Images are processed in your browser and never uploaded.
Do image adjustments affect exports?
Yes. Brightness, contrast, grayscale, and inversion apply to the whole image in both preview and export. The project retains the original. Disclose adjustments as required by your publication.
How can I continue after reloading?
There is no automatic saving. Download an editable JSON project before leaving and restore it with Open project. Keep the JSON for further editing; PNG and SVG are presentation exports.
Original images are retained; display adjustments apply to exports. No automatic result inference. Save your project before reloading.