Add film grain in Photopea (free, in the browser)

Open the photo at photopea.com, place a grain plate, set it to Overlay and lower the opacity. No account and no Photoshop needed.

Photopea is a free photo editor that runs in the browser and works almost exactly like Photoshop. Adding film grain there takes about a minute, and you do not need an account.

Step by step

1. Download a grain plate. For most photos start with ISO 400 medium grain.
2. Go to photopea.com and open your photo with File → Open.
3. Choose File → Open & Place and pick the grain JPG. It lands as a new layer. Press Enter to confirm the placement.
4. In the Layers panel, change the blend mode from Normal to Overlay. The grey disappears and only the grain stays.
5. Set the layer Opacity to 30–60%.
6. Save with File → Export as → JPG.

If the grain looks too big or too small

Select the grain layer, press Ctrl+T (Cmd+T on a Mac) and drag a corner. Bigger grain looks like a faster film. If your photo is much larger than 3000 px, scale the plate up rather than repeating it.

Colour or mono?

Mono plates add texture without changing colours. Colour grain adds a light red, green and blue speckle, like a scanned colour negative. If skin starts to look noisy, switch the blend mode to Soft Light.