Archaeology Photo Scale
Add a scale bar or colour card to a finds or excavation photo, sized from something of known length in the picture.
or browse filesdrop an image here or paste
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Add a scale bar or colour card to a finds or excavation photo, sized from something of known length in the picture.
or browse filesdrop an image here or paste
Drag the ends of the blue line onto something of known length in the photo - a ruler, a tape, a measured find - and type that length.
Scale typeAn archaeological photo without a scale - a find on the bench, a section, a trench - cannot be measured later, and a scale that is too small or half out of focus is almost as bad. This tool adds a clean scale to a photo you already have. Drop the photo in, drag the blue line along something of known length in the picture, type that length, and a scale bar appears at exactly that scale. Choose the Scale type - a plain bar, an IFRAO-style colour card with colour and grey patches, a grey scale, or a bar with a north arrow - and a Length from 1 cm for small finds to 1 m for a trench. Drag the scale to where it belongs, add a site code or context number as a Label, and download the full-resolution photo with the scale in it.
The scale is only as good as the reference. The best one is a ruler, a tape or a photo scale lying in the same plane as the object - then this tool turns a small, tilted or partly hidden scale into a clear bar beside the find. A measured dimension works too: the length of a find you recorded with callipers, a known brick or tile size, a grid square on a planning frame. Drag each end of the line exactly onto the two points and use the magnifier for precision; the image details card shows the resulting pixels per centimetre. Every bar length keeps the same proportions, so a 1 m bar is ten 10 cm segments rather than a long thin strip. For a scale to print and lay in the shot, use the Archaeology Scale Generator.
The download is the original photo at full resolution with the scale drawn in - the calibration line and handles are for the screen only and never appear in the file. PNG keeps every pixel and the sharp edges of the bar; JPG matches most camera files and keeps the size down; WebP is smaller still. The format follows the photo you opened. Copy puts the result on the clipboard for a report or a database record, and on a phone the share button opens the system share sheet.
Site photos can be sensitive: an unpublished find, the location of a site that attracts looters, a context number that ties a picture to a dig. A service that added the scale on a server would see all of it. This one does not - the photo is decoded, measured and drawn on your own device, the download is written from memory, and nothing is sent anywhere. Once the page is open it also works without a connection.
Not quite. A physical scale photographed next to the object is the standard, because it shares the object's plane, focus and lighting. A scale added here is exactly as accurate as the reference you calibrate against, and only for things at the same distance from the camera - in a photo taken at an angle, parts nearer or further away are at a different scale. Use it when the photo already contains something measured, or to add a legible bar beside a small or tilted one.
The IFRAO standard scale, from the International Federation of Rock Art Organisations, is a card with a scale bar, colour patches and a grey scale, photographed with rock art so the picture can be colour-corrected later. The Colour card type draws the same layout. Patches added after the shot show the intended colours, not how the scene was lit, so for colour correction photograph a real card; the drawn card serves as a scale and a reference key.
No. The photo, the calibration and the label stay on your device; the scale is drawn in the browser and the file is saved from there.