Pick a colour from any image or PDF — no upload.

PDF brand guidelines are the canonical example of a document that specifies colours beautifully and gives you no practical way to use them. Fifty pages about tone of voice, a gorgeous colour chip on page 12, and no hex code anywhere near it.

Check for a declared value first. Before sampling anything, search the document for #, "HEX", "RGB", "CMYK" or "Pantone". Most guidelines list values in a table, and if the PDF has selectable text you can copy the exact authored string. A declared value always beats a reconstructed one.

If you must sample, zoom first. PDF viewers render at screen resolution, so a small swatch is heavily antialiased and its edges are unreliable. Zoom to 200% or more, then sample the middle of the largest flat chip. Brand guidelines usually include large colour blocks specifically for this — use those, never the small inline examples.

Beware CMYK. Print-oriented PDFs often specify colours in CMYK. What your screen shows is a conversion, and CMYK-to-RGB conversion is not lossless or unique — different converters give different results. If the guideline is print-first, sampling gives you an approximation. Ask for the digital value.

Images have their own failure modes, and all of them produce a value that's nearly right — which is worse than obviously wrong, because it looks subtly off next to the real asset and nobody can say why.

JPEG artefacts. JPEG stores colour at reduced resolution and introduces ringing near sharp edges. Screenshots sent through messaging apps are almost always re-compressed JPEG. The test: sample the same region twice, a few pixels apart. If the values differ, you're in an artefact zone — move toward the centre until two samples agree. PNG is lossless and doesn't have this problem, so ask for PNG when you can.

Transparency. A semi-transparent pixel composites against whatever is behind it. Open the image on a white background and sample a translucent region and you get the colour blended with white. Test by viewing the same image against a dark background — if the value changes, that area isn't opaque.

Text and thin strokes. Subpixel antialiasing lights individual red, green and blue subpixels to fake horizontal resolution. Sampling a letterform edge gives you a value tinged orange or cyan that exists nowhere in the design. Sample only from solid areas.

SVG is different, and better. An SVG is XML — open it in a text editor and the fill values are literal strings. That's the authored value with no rendering in between, and it's the most reliable source there is.

Most "pick a colour from an image" tools work by having you upload the file. The image goes to a server, or at minimum into the page, and the tool reads pixels from it with a canvas.

That's an unnecessary data transfer for a task this small, and it also constrains what you can sample — you need the source to be an exportable image file, which rules out a PDF in your native viewer, a live web page, a native application, or a paused video.

This picker works differently. It uses the browser's built-in EyeDropper API, where the browser process reads the pixel directly off your screen at the OS level. Whatever is visible — a PDF in Preview, an image in your file manager's preview pane, a Figma board, a paused video — is sampleable, because the browser doesn't care which application painted it.

And the page receives exactly one thing: the colour string you clicked. No file, no image data, no screenshot. There's nothing to upload because there's nothing to upload from — the file never enters the page at all.