Photo filters and adjustments

The everyday adjustments, without opening an editor

Brightness, contrast, saturation, warmth, a vignette and a blur, plus a handful of one-click looks. Nothing here needs an account, an upload or a download of a 200 MB application — it runs in the page, on your own processor, on an image that never leaves your device.

It is fast because the browser does this in hardware. A twelve-megapixel photo adjusts in the time it takes the file to open, where uploading the same file would take several seconds before anything happened.

Warmth is the one that fixes real photographs

Most filter tools offer brightness, contrast and saturation because those are the three the browser provides directly. The control that actually rescues an ordinary bad photo is colour temperature — the indoor shot under a tungsten bulb that came out orange, or the shaded outdoor one that came out blue.

There is no CSS filter for it, and the two substitutes people reach for are both wrong. Hue-rotate turns the entire colour wheel, so greens go magenta and skin goes strange. Blending a warm wash over the picture brightens it — measured here, an orange wash at +70 took a mid-grey from a luminance of 128 to 142, which is a brightness slider wearing a different label.

What a white-point shift actually is, is a per-channel gain: red up and blue down to warm the picture, the reverse to cool it. Green is then solved for rather than left alone, because red and blue carry very different weights in perceived brightness — 0.299 against 0.114 — so moving them by equal and opposite amounts does not cancel out. Setting green so that a grey keeps its exact luminance holds the neutral axis to within 1% at any setting, which means the slider changes colour and nothing else.

The presets are starting points

Greyscale, sepia, invert, high contrast, faded, cool, warm and a hard mono. Each one sets the sliders rather than replacing them, so you can pick the look you want and then adjust it — which is usually necessary, because a preset cannot know how bright your original was.

Greyscale and invert are worth calling out as genuinely useful rather than decorative: greyscale is what a document scan often needs before printing, and inverting is the quickest way to read a photograph of a screen taken in dark mode.

The vignette

Darkening the corners draws the eye to the middle. It is a real compositional tool and it is very easy to overdo — at anything above about 40% it stops reading as light falloff and starts reading as an effect. It is applied as a radial gradient over the finished image, so it composites the same way whatever else you have adjusted.

Batch

Up to twenty images at once with the same settings, returned as a zip. That is the case worth having: a set of photos shot in the same room under the same bad light needs the same correction, and applying it one at a time is the tedious part.

What this is not

It is not a raw developer, it has no curves or levels, and it cannot select part of an image. Those are real tools for real editing and they belong in an application. This is for the adjustment you want to make in ten seconds without installing anything — which is the great majority of them.