# How to Fill an Area with Colour in Photasium

> Fill an area with colour in the browser without uploading or creating an account. Open Fill in Photasium, set the tolerance, and click.

Fill

A sky, a backdrop, or a selected rectangle can take a solid colour in one click. In Photasium that happens in the tab: the file never goes to a server.

## Flooding a colour

Fill paints every connected pixel that matches the one you clicked, within the tolerance. [Brush](https://photasium.com/guides/how-to-paint-and-erase-on-a-photo.md) is the stroke you drag.

Picker (I) samples a colour from the photo into the foreground well. Option-click sets the background. Fill uses those two wells: click for foreground, Option-click for background.

## A block of colour

A post can use a flat sky or a colour behind type. If the sky is even enough, Fill takes it in one click. Raise tolerance if the flood stops short of the edges.

Fill on a [new raster layer](https://photasium.com/guides/how-to-use-layers.md) if you want to hide the colour later without touching the photo underneath.

A listing often wants a clean backdrop. Click the table or wall with Fill if that colour is connected. Sample the replacement colour with the Picker first, or Option-click Fill to use the background well.

A name or a number on a screenshot can sit inside a Marquee (M). Delete clears those pixels. Option-Delete fills the selection with the foreground, and ⌘⌫ fills it with the background.

[Canvas Size](https://photasium.com/guides/how-to-resize-a-photo.md) can add a margin around a print. Fill that new area with a colour sampled from the photo, or with the background well, so the border matches the page.

## Filling in Photasium

1. **Open a photo.** Open the [editor](https://photasium.com/editor), then File → Open, or drop an image on the canvas.

2. **Choose Fill.** Click Fill in the toolbar, or press G.

3. **Set the tolerance.** Tolerance is in the options bar, from 0 to 255. A higher value takes in more nearby colour. Start low if the flood jumps into the subject.

4. **Click to fill.** Click a pixel to flood connected colour with the foreground. Option-click uses the background. Picker (I) samples from the photo. If the active layer is type, Fill adds a new raster layer. Clicking type asks you to rasterize first. A locked layer will not accept fill.

Fill always stays on connected pixels. Wand (W) selects matching colour, with its own tolerance, and Contiguous off selects every match on the layer. Marquee (M) draws a rectangle or an ellipse. Shift constrains the shape. Option draws from the centre. New, Add, and Remove sit in the options bar. With Wand, Shift-click adds and Option-click subtracts.

If a selection is active, Fill only runs inside it. Deselect clears the marching ants. Delete clears the selected pixels. Undo restores the previous fill.

## Colour on the layer

The fill sits on the raster layer, nothing was uploaded, and undo restores the previous pixels. If the flood went too far, drop the tolerance and try again, or undo and draw a selection first.

Download PNG, JPEG, or WebP if you need a file to send. Come back later and the document is still listed under the editor, until this browser’s storage is cleared. Fill sits with the other [photo editing tools](https://photasium.com/#fill): [paint a stroke](https://photasium.com/guides/how-to-paint-and-erase-on-a-photo.md), [keep it on its own layer](https://photasium.com/guides/how-to-use-layers.md), [export a listing](https://photasium.com/guides/how-to-export-png-jpeg-or-webp.md).

[Open photo editor](https://photasium.com/editor)