What does 100 percent mean?

The neutral point — the colour is unchanged. Values below it darken the colour and values above it lighten it, with the same amount of change either side.

Is this a real exposure adjustment?

No. It moves the colour's lightness rather than simulating how light reaches a sensor, so highlights never clip and a colour pushed far enough simply becomes pale.

Are hue and saturation kept?

Yes, through both directions. That is what makes the tool usable for hover and pressed states, where the variant has to stay recognisably the same colour.

Does it report the resulting value?

Not as text — the result is a swatch the colour can be read from. There is no lightness figure, no contrast check and no export.

Is this the same as photographic exposure?

No. The slider runs from zero to two hundred with a neutral of one hundred, and the operation is a scaled lightness change — lightness is shifted by up to half in OKLCH — rather than a multiplication of the light reaching a sensor, so nothing clips the way a real exposure change would.

Exposure Adjuster

Color

brightness: 100%

Result

#3b82f6

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The exposure adjuster brightens or darkens a colour from a slider that runs from 0 to 200 percent and sits at 100, showing the result in a large swatch.

What is Exposure Adjuster?

The controls are a colour field, a slider labelled brightness with a range from zero to two hundred and a starting value of one hundred, and a result card holding one large swatch. One hundred is the neutral point: below it the colour is darkened, above it the colour is lightened, and the swatch follows the slider continuously.

The arithmetic is a scaled lightness change rather than a photographic exposure.
Leaving the neutral point by twenty points applies a lighten or a darken of (20/200) — a tenth of the operation's full strength — so the two halves of the slider produce symmetric amounts of change around the neutral.
That means the fifty-point mark is a quarter of the way to black and the hundred-and-fifty mark a quarter of the way to white, which makes the slider easy to reason about even though no formula is shown anywhere on the page.

What it does not model is light.

An exposure control in photography multiplies the light reaching a sensor, which clips highlights and preserves the character of the shadows; this tool moves a colour's lightness directly, so a colour pushed far up the range simply becomes paler and eventually reaches white.
Treating the slider as a lightness control rather than as a camera setting gives the results you would expect from the code.

Hue and saturation are preserved through both directions, which is what makes the tool useful in a palette rather than only on a single swatch. Producing the hover, pressed or disabled variant of a colour is the everyday case: a hundred and ten is a subtle lift, a hundred and thirty is a noticeably lighter version for a hover state, and ninety gives the pressed version while keeping the hue recognisable.

The page offers no measurement and no export. There is no lightness readout, no contrast check between the adjusted colour and anything it might sit on, no comparison against the original colour beyond seeing the swatch, and no palette view for adjusting a set together. It is also only a preview: the value has to be taken away by reading the swatch.

The two halves of the slider are useful in different places. Lighter variants — one hundred and ten through one hundred and thirty — cover hover states, disabled surfaces and chart backgrounds; the darker half covers pressed states, borders drawn on light surfaces and text set on pale fills. Because one control reaches both, a complete state set can be built from a single colour without switching tools, and the neutral point gives a reliable way back to the original value when an experiment has gone too far.

Limits: one colour, a 0 to 200 range around a neutral of 100, a lightness operation rather than a true exposure, and no readout, history or export. As an exposure adjuster it does the two jobs the name implies — brighten a color above the neutral point or darken a color hex value below it — and as a color lightness control with an exposure slider it is the simplest way to move a colour without touching its hue.

How to use Exposure Adjuster

Pick the colour in the field.
Set the slider below 100 to darken, above 100 to lighten; it runs 0 to 200.
Read the adjusted colour from the result swatch, which updates as the slider moves.

When to use Exposure Adjuster vs related tools

Use this when a colour needs a lighter or darker variant for a state, and the hue must stay put. Use the lighten or darken tools when the amount should be stated as a fraction, or the tint and shade generators when a whole ladder is wanted instead of one step. The lighten tool and darken tool make the same lightness change from a percentage set directly, and the CSS filter generator writes a brightness value into a filter declaration.

Privacy & Security

This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.