Image Gamma Editor
Set gamma by the number a spec, a monitor or a render pipeline actually named, 2.2, 0.45 or anything between, and watch the picture follow. Black and white stay put.
or browse filesdrop an image here or paste
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Set gamma by the number a spec, a monitor or a render pipeline actually named, 2.2, 0.45 or anything between, and watch the picture follow. Black and white stay put.
or browse filesdrop an image here or paste
Most photo controls ask you how much lighter you want it. Gamma asks for a number, and usually you already know which one: 2.2, because that is the sRGB and Rec.709 curve; 0.45, because that is the same curve run backwards; 1.8, because an old Mac profile said so; 2.4, because a broadcast spec did. This is the gamma editor for exactly that job. Drop a picture on the page, type the value into the field beside the slider, and the image follows while you type. Nothing is uploaded and nothing is guessed for you.
People come looking for a gamma changer, a gamma increaser, a gamma adjuster or a gamma corrector, and they are all the same control: one number, applied in both directions. The slider and the field are the same control too. Drag for a feel, type for a value, or press one of the named stops: 0.45, 1.00 and 2.20 sit under the slider, and the 1/γ button next to them swaps whatever is set for its reciprocal, so 2.20 becomes 0.455 and back again in one press. The scale runs from 0.25 to 4.00, which covers every gamma a display profile, a game, a render pipeline or an image spec is likely to name.
Drop a JPG, PNG or WebP onto the page, or paste one from the clipboard. Then either type a gamma, drag the slider, or press Auto and let the tool pick one. Hold the compare button in the corner of the image to see the original for as long as you hold it. The ⓘ button next to it opens the numbers: the gamma you set, the exponent it becomes, what mid grey 128 turns into, and the size of the file you will get. Any of those values copies to the clipboard when you click it.
Download as PNG for a lossless file, or as JPG or WebP for a smaller one; a JPG you loaded comes back as a JPG by default. The saved file carries the gamma in its name, so photo-gamma-2.20.png is still self-describing a week later.
This tool follows the convention every image editor uses, the one behind a Levels midtone slider and behind -gamma on the command line:
out = in ^ (1 / gamma)
So a gamma above 1.0 raises the midtones and the picture gets lighter, and a gamma below 1.0 pushes them down and it gets darker. Gamma 1.0 is the original, untouched. If you want to increase gamma, go right; to decrease it, go left. It is worth stating plainly because the wording is genuinely ambiguous in the wild: some documentation describes the exponent instead of the gamma, and then every direction reads backwards.
Two things never move, at any setting. Pure black stays pure black and pure white stays pure white, because 0 and 1 are fixed points of a power curve. That is the structural reason a gamma adjustment cannot blow out a sky or crush a highlight the way a brightness gain can: the curve bends the tones between the ends and leaves the ends alone.
Gamma comes in reciprocal pairs, and knowing which half you are applying is most of the confusion. A camera or an editor stores an ordinary JPG or PNG with its values already gamma encoded, roughly to the power 1/2.2. Your monitor decodes them by raising them back to the power 2.2. The two cancel, which is why a normal photo looks normal.
Setting 2.2 here applies the encode curve one more time: it is what you do to linear light data to make it displayable, and on an already encoded photo it lifts the midtones and brightens. Setting 0.45, which is 1/2.2, applies the decode curve and darkens. Be precise about what that means: this changes the numbers stored in the file, it does not retag the file or convert it to a linear color space, so a picture at gamma 0.45 is still an sRGB file, just a darker one. If a pipeline handed you an image that was mistakenly encoded twice, or one that was never encoded at all, applying the opposite half here is the fix, and the 1/γ button is there so you never have to work out the reciprocal by hand.
The pair also round trips. Apply 2.2, save, reload and apply 0.455 and the picture comes back within one level out of 255 on every pixel. Doing it in the other order does not: darkening first crushes shadow values toward zero, and lightening cannot bring back what the file no longer stores. Brighten first, darken second, if you have the choice.
These are four different transformations and they are not interchangeable.
A brightness control adds or scales, so every tone moves by the same amount and the bright end hits 255 and clips first. That is the brightness changer, and it is the right tool when you genuinely want a uniform shift. Exposure works in camera stops, a multiplication in linear light that mimics opening the aperture; the exposure tool does that, with separate highlight recovery. Lightening is this same power curve dressed in a friendly scale from -100 to +100 for people who want a photo to look better and do not care what the exponent is; that is the lighten tool, and if you are here because a photo is too dark rather than because a number is wrong, it is probably the page you want. Contrast rotates the tones around the middle instead of bending them, which is the contrast editor.
Gamma is the one you use when the number is the point: when a spec, a viewer, a game engine, a texture pipeline or a colleague's note named a value and you need that exact transformation applied and repeatable.
The textbook gamma one-liner runs the power on each colour channel separately. It is correct on grey, and on saturated colour it quietly desaturates: a strong red of (200, 50, 50) at gamma 2.2 comes out as (228, 122, 122), which has lost more than half its colour. That washed-out look is the usual complaint about gamma correction in image processing.
This tool works out the curve once per pixel from that pixel's brightest channel and applies the resulting gain to all three channels in linear light, so (200, 50, 50) comes out as (228, 58, 58): the same red, lighter. On a neutral pixel the two methods are identical byte for byte, and a gamma value is defined against a grey ramp, so a calibration wedge or a grey step chart processed here matches the textbook formula exactly. Only the colour behaviour is different, and it is different in the direction you want.
Auto measures the average perceptual brightness of the visible pixels and searches for the gamma that puts that average on mid grey, which is roughly where a normally exposed photo sits. It is a real search over the actual result, not a formula applied to the average, because a curve driven by each pixel's brightest channel lifts a colourful picture less than a grey one and a closed form lands short.
It only ever sets the value, so nothing is hidden: you see the gamma it chose, and you can type a different one. It always reads the original image rather than what is currently on screen, so pressing it twice gives the same answer. If a picture is so dark or so light that the whole scale cannot reach mid grey, it stops at 0.25 or 4.00 and says so instead of pretending.
Worth saying because the same words are used for two different jobs. If you are trying to turn up the gamma on a monitor, in a game, or on a TV, that is a display setting and no web page can change it. What this tool does is bake a gamma transformation into the picture, so the file itself is different afterwards and looks that way everywhere. Loading a gamma calibration image here and adjusting it will not calibrate anything; it will produce an adjusted copy of the chart. For finding out where an image actually sits, the histogram viewer shows how the tones are distributed and how much is stuck at either end.
The preview and the download run the identical table over the pixels, so what you see is what you save, at the full resolution of the file you loaded. At gamma 1.00 the image passes through untouched, byte for byte. Transparency is preserved and the alpha channel is never touched by the curve, so a PNG with a transparent background stays transparent. The compare view is a viewing aid and never ends up in a saved file.
All of it happens on your device through the canvas API, so no image is transmitted anywhere and the page keeps working offline once it has loaded. There is no signup, no watermark and no size limit beyond what your browser can hold. For neighbouring edits there is the color temperature editor for warmth and white balance, the color grading tool for shadow, midtone and highlight colour, and the hue shifter.
Open the picture here, then type a gamma into the field beside the slider or drag the slider to it. The preview updates as you type. Press one of the stops for 0.45, 1.00 or 2.20, or press Auto to have a value chosen from the image. Then download at the original resolution as PNG, JPG or WebP. No account, no upload, no watermark.
Brighter. This tool applies out = in ^ (1 / gamma), which is the convention in image editors, so gamma 2.2 lifts the midtones and gamma 0.45 pushes them down. Gamma 1.0 leaves the picture exactly as it was. Some documentation quotes the exponent rather than the gamma, and in that form the directions look reversed, which is where most of the confusion comes from.
It is a power curve applied to the tone values of an image, out = in ^ (1 / gamma). It exists because both human vision and display hardware respond non-linearly to light, so image files store values on a curved scale rather than a linear one. Gamma correction moves an image between those scales, or bends its midtones deliberately. Because the curve fixes 0 and 1, it changes the middle of the range far more than the ends.
If a spec, a profile or a piece of software named one, use that. Otherwise: 2.2 is the standard sRGB and Rec.709 curve and is the most common single answer, 0.45 is its inverse, 1.8 belongs to older Apple systems and 2.4 to broadcast video. For plain photo work, small moves are usually enough; something between 1.1 and 1.5 lifts a slightly dark picture without looking processed, and Auto is a reasonable starting point.
Yes, and that is the main practical reason to use gamma rather than brightness. A power curve keeps 0 at 0 and 255 at 255 at every setting, so the brightest pixels cannot move past white no matter how far you increase gamma. A brightness gain multiplies instead, so the bright end reaches white first and detail there is lost.
Because most implementations run the curve on the red, green and blue channels separately, which pulls saturated colours toward grey. This one derives a single gain per pixel from its brightest channel and applies it to all three, so hue and saturation survive the adjustment. Hold the compare button and you will see the colours stay the same colour, only lighter or darker.
No. This tool changes the image file, not your display. Monitor, TV and in-game gamma are settings in the display, the graphics driver or the game itself, and a web page cannot reach them. What it is good for is preparing an image so it reads correctly on a display you already know is dark or bright, or undoing a gamma transformation that was baked into a file by mistake.
Yes. JPG, PNG and WebP all load, transparency is preserved, and the alpha channel is never touched by the curve. A transparent background stays transparent in the download, and a PNG saved from here is lossless.
No. The image is decoded, adjusted and encoded in your browser, at preview and at full download resolution alike. Nothing is sent to any server, and the tool keeps working with the network disconnected once the page is open.