Channel Mixer: Rebuild Each Colour From the Others
Every output channel is built from any combination of the three inputs, with a live total that tells you whether the row is neutral. It is the proper way to convert to black and white, because you choose which colours become which greys.
Drop images here
or click to browse · or paste with Ctrl+V
JPG · PNG · WebP · GIF · BMP · AVIF
Output channel
A flat offset added to this output channel after the mixing.
Presets
Your photos are never uploaded. The channel mixing and the export both run inside this browser tab.
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Everything this tool does
The total is shown, not hidden
A row summing to a hundred leaves brightness unchanged; anything else also changes exposure. The indicator turns green at a hundred so you always know which you are doing.
Identity is an exact no-op
With the identity matrix and no constants, a whole test image comes back byte for byte unchanged, which is the check that no rounding is creeping in anywhere.
Proper black and white conversion
On a mid red and a mid green of similar brightness, the standard recipe separated them by 11 levels while a red filter mix separated them by 140.
Filter presets from film
Red, green and blue filter mixes, which are the same tools landscape photographers used on film to control how colours became greys.
Full nine coefficient control
Every output channel can be built from any combination of the three inputs, including negative amounts, which is what makes deliberate channel swaps possible.
Per-channel constant
A flat offset added after the mixing, for lifting or crushing one channel independently of how it was built.
Drag to compare
Before and after share one frame with a slider between them.
Six purpose-built presets
Identity, standard mono, red, green and blue filter conversions, and a deliberate red and blue swap.
Batch with one ZIP
Apply one mix across a whole set and take everything as a single archive built in your browser.
Nothing is uploaded
No server, no queue, nothing to delete afterwards. Close the tab and every trace of the image goes with it.
What the numbers mean
Each row says what the output channel is made of. A row of 100, 0, 0 means the output red is simply the input red. Change those numbers and you are rebuilding that channel from the others.
| Setting | What it does | Try | Good for |
|---|---|---|---|
| Row total 100% | brightness unchanged | always aim for this | Neutral mixing |
| Row total above 100% | that channel brightens | deliberately | Lifting one colour |
| Mono 100, 0, 0 | red filter black and white | dark skies | Classic landscape |
| Mono 0, 100, 0 | green filter | foliage separation | Portraits and plants |
| Mono 0, 0, 100 | blue filter | gritty, high grain | Dramatic, harsh |
| Mono 30, 59, 11 | standard luminance | the safe default | General conversion |
| Constant | flat offset after mixing | -15 to +15 | Lifting or crushing |
9
mixing coefficients
Live
neutral total indicator
0
files uploaded
Exact
identity no-op
ZIP
batch download
Free
no account needed
FlipMyFormat vs other channel mixers
| Capability | FlipMyFormat | Typical free tool |
|---|---|---|
| Files stay in your browser | ||
| Live indicator of whether the row is neutral | ||
| Identity matrix is an exact no-op | ||
| Monochrome mode with filter presets | ||
| Per-channel constant offset | ||
| Batch ZIP download without paying | ||
| No watermark on the output |
How to use a channel mixer, especially for black and white
A channel mixer answers a question most tools never ask: what should each output channel be made of? Normally the output red is simply the input red, which is what the identity setting means, and every number you change moves away from that. In colour work this is a specialist tool, used for correcting a badly cast scan, swapping channels deliberately, or reproducing the response of a particular film. In black and white it is the single best conversion method there is, and it is worth understanding why. When you desaturate a photograph the software applies one fixed recipe, usually something close to thirty percent red, fifty-nine green and eleven blue, and every image gets the same treatment. But two colours that happen to have the same brightness will become the same grey, so a red flower against green leaves can vanish entirely. Photographers solved this on film with coloured filters: a red filter lightens red things and darkens blue things, which is why classic landscape prints have such dark skies. The monochrome mode here is exactly that control. Push the red to a hundred and the blue to zero and you have a red filter, and your sky goes dark while brickwork lightens. The one number to watch throughout is the total. If the three sliders in a row add up to a hundred, the overall brightness is unchanged and you are purely redistributing colour. Away from a hundred you are also changing exposure, which the indicator tells you plainly rather than leaving you to discover it.
- 1
Add your photos
Drag them in, click to browse, or paste with Ctrl+V. Photos with clearly different colours show the effect of mixing most.
- 2
Choose colour or monochrome
Monochrome mode is the classic use: you decide which colours become which greys, which is what a coloured filter did on film.
- 3
Keep the total at 100 and export
The indicator turns green when the row is neutral. Away from 100 the brightness shifts, which is sometimes what you want.
Why the row total decides the brightness
A hundred percent means neutral
Each output channel is a weighted sum of the three inputs, and the weights are percentages. Consider a neutral grey pixel where red, green and blue are all the same value: the output is that value multiplied by the sum of the three weights, divided by a hundred. If the weights add to a hundred the grey comes out exactly as it went in; if they add to a hundred and twenty it comes out twenty percent brighter. That is the entire reason the total matters and why it is displayed rather than hidden. We check the property directly at both ends: with the identity matrix and no constants, an entire test image comes back byte for byte unchanged, and with a monochrome row of thirty, fifty-nine and eleven, a mid grey pixel comes back at exactly its original value.
Why this beats desaturating
Desaturation applies one fixed recipe to every photograph, so any two colours with similar brightness collapse to the same grey and disappear into each other. A red flower against green leaves is the classic casualty. Choosing the weights yourself is what film photographers did with coloured filters, and it produces genuinely different pictures from the same negative. We measured it on a test pair, a mid red and a mid green of similar brightness. Under the standard luminance recipe they came out 11 levels apart, which is very nearly the same grey. Under a red filter mix of one hundred, zero, zero they came out 140 levels apart, which is the difference between a flower you can see and one you cannot.
What people use it for
Black and white conversion
The best method there is, because you decide which colours become which greys rather than accepting one fixed recipe.
Dark dramatic skies
A red filter mix darkens blue sky and lightens clouds, which is how classic landscape prints got their contrast.
Separating foliage
A green filter mix lightens leaves and separates them from each other, which desaturation flattens together.
Portrait black and white
Slightly red-weighted mixes smooth skin, which is why portrait photographers favoured them on film.
Correcting badly cast scans
When one channel of a scan is unusable, rebuilding it from the other two often rescues the image.
Infrared style conversions
Heavy green weighting in monochrome approximates the bright foliage of infrared film.
Deliberate channel swaps
Swapping red and blue produces a surreal look that is exactly reversible.
Film response emulation
Different stocks responded differently to each colour, which a mix can approximate.
Six tips worth knowing
Watch the total. At a hundred you are purely redistributing colour; away from it you are also changing exposure.
For black and white, start from the standard recipe and then push one channel to see what it does to your specific photo.
A red filter mix darkens blue skies and lightens skin and brick. A blue filter does the opposite and looks harsh.
Negative values are allowed and useful. Subtracting a channel can pull apart two colours that a positive mix flattens together.
If a scan has one bad channel, try rebuilding it entirely from the other two rather than trying to correct it.
Use identity as your reference point. Any number away from it is a deliberate decision rather than a default.
Troubleshooting
The photo got much brighter or darker
Your row total is away from a hundred. The indicator tells you the sum; bring it back to a hundred to mix without changing exposure.
Colours look completely wrong
That is what a channel mixer does when pushed. Reset to identity and change one number at a time to see what each does.
My black and white looks flat
You are probably near the standard recipe, which treats every photo the same. Push one channel up and the others down to separate the colours that matter.
Areas have gone pure white or black
A row total well above a hundred, or a large constant, pushes values out of range where they clip. Reduce one of them.
Frequently asked questions
What does a channel mixer do?
It rebuilds each output colour channel from any combination of the three input channels. Normally output red is just input red; a mixer lets you make it from green and blue instead, or from all three.
Why does the total matter?
Because for a neutral grey pixel the output is the input multiplied by the sum of the row's weights. A total of a hundred leaves brightness unchanged; a hundred and twenty makes everything twenty percent brighter.
Why is it the best way to convert to black and white?
Because desaturation applies one fixed recipe, so two colours of similar brightness become the same grey and disappear into each other. Choosing the weights lets you separate them.
Can you show that difference?
On a mid red and a mid green of similar brightness, the standard luminance recipe left them 11 levels apart, which is very nearly the same grey. A red filter mix left them 140 levels apart.
What is a red filter mix?
Weighting the monochrome output entirely toward red, which lightens red things and darkens blue ones. It is the digital equivalent of the red filter landscape photographers used to get dark dramatic skies.
Are negative values useful?
Yes. Subtracting a channel can pull apart two colours that a positive mix flattens together, and it is essential for some scan repairs. Just keep an eye on the row total.
What does the constant do?
It adds a flat offset to that output channel after the mixing, which lifts or crushes it independently of how it was built.
Is the identity setting really a no-op?
Yes, exactly. With the identity matrix and no constants, a whole test image comes back byte for byte unchanged, with no rounding drift anywhere.
Can it fix a scan with a bad channel?
Often, yes. If one channel is unusable, rebuilding it entirely from the other two frequently rescues an image that looks beyond help.
How is this different from selective colour?
Selective colour changes specific hue families. A channel mixer works at the level of the channels themselves, which is a lower level operation affecting every pixel according to its composition rather than its hue.
Why did my photo get much brighter?
Your row total is above a hundred. The indicator shows the sum and turns green when the row is neutral.
What is a good starting point for black and white?
The standard thirty, fifty-nine, eleven recipe, then push one channel and pull the others to keep the total at a hundred. Watch what happens to the colours you care about.
Can I swap two channels?
Yes, and there is a preset for it. Swapping red and blue is a pure permutation, so applying it twice returns the original exactly.
Are my photos uploaded to a server?
No. The mixing and the export both run in your browser using the canvas API. Nothing is sent anywhere.
Which format should I export?
Keep the original for photographs, at quality 90 or above. Mixing channels can amplify the colour artefacts JPEG stores at half resolution.
Is transparency preserved?
Yes for PNG and WebP output. The alpha channel is untouched. JPG has no alpha, so transparent areas are filled with the background colour first.
Can I process a batch?
Yes. Add as many photos as you like and the same nine coefficients and constants are applied to each.
Does it add a watermark or need an account?
No to both. No sign-up, no email wall, no daily limit and no watermark on the output.