You add a look you liked in the thumbnail, and the video gets worse. Not wrong-coloured exactly. Just flat, a bit grey, a bit dark, like someone let the air out of it.

If that is happening to every preset rather than one, the cause is probably not the preset.

What you are actually seeing

The tell is where the damage lands. Highlights survive, deep shadows survive, and everything in between gets dragged down and desaturated. Faces go waxy. A bright room reads as an overcast one. The picture looks like it lost a layer.

The same video frame before and after a colour grade is applied.

That specific signature, midtones crushed while the ends hold, is the fingerprint of a contrast or saturation adjustment applied to the wrong kind of numbers.

The cause: two different meanings of the same value

Grading recipes are written in what colourists call display-referred terms. When a recipe says "contrast 1.2" or "lift the blacks 5 percent", it means five percent of what you see on a screen. That is the grammar every published look, every LUT description and every tutorial uses.

Image pipelines frequently do not work in those numbers. Apple's Core Image, for one, applies filters in linear light by default, which is the physically correct space for things like blurs and exposure because light adds up linearly in the real world.

The two are not interchangeable. A midtone that sits at 50 percent on your display sits near 21 percent in linear light, because the transfer function between them is a curve, not a line. Run a recipe written for the first set of numbers against the second and every midtone adjustment lands far lower than intended. The result is exactly the symptom above: a picture that looks like it has been pulled toward the floor.

Nothing in that chain is broken. Each part is doing what it says. They simply disagree about what "50 percent" means.

Why turning the filter down does not fix it

The instinct is to pull the intensity slider back until the video stops looking bad. That does reduce the damage, because you are applying less of a wrong thing. It also means you never get the look you picked, at any setting. You are choosing between "wrong" and "barely there".

The same logic explains why the problem seems to affect every preset in a catalogue at once. A single ugly preset is a taste disagreement. An entire catalogue that reads as muddy is a pipeline telling you something.

How to tell which one you have

Three checks, in order of speed:

  1. Try several presets that should look nothing alike. A warm film look and a cool clinical one should disagree strongly. If both land in the same grey neighbourhood, that is the pipeline, not the presets.
  2. Watch the midtones specifically. Put something mid-grey in frame, or use a face. Highlights and blacks holding while the middle sinks is the signature.
  3. Check exposure separately. Raising exposure by a stop is a genuinely linear operation and usually behaves correctly even when the tone controls do not. If exposure feels right and contrast feels wrong, that gap is the clue.

What the fix actually is

The pipeline has to switch into display space for the stage that expects it, and switch back.

That is the whole repair: bracket the tone and colour-board stage so brightness, contrast, saturation and lift or gamma or gain run on the numbers their recipes were written against, then return to linear for everything that genuinely wants linear. Blur, exposure and white balance stay where they were, because those are physical operations and linear is correct for them.

We did exactly this in Zella on iPhone, and then re-derived the entire look catalogue against current colourist references rather than patching the old values. The phone catalogue is now 42 looks in the free tier, up from 25, plus three Founder grades. Eleven of the new ones are archetypes people actually ask for by name: Portra 400, Clean Cream, Y2K Digicam, Espresso, and the 2026 creator pack - Soft Glow, Bright Airy, Peachy, Terra Brown, Retro Halation, Tokyo Soft and Punchy. Nothing moved behind a paywall in the process. The free set only got larger.

There is also a test suite guarding it now, which matters more than the count. A preset that darkens mid-grey, tints the whites or washes the colour out fails the build instead of shipping. That is the kind of bug that is easy to reintroduce by hand-tuning one value.

The other dull: a vignette baked into the filter

There is a second way a filter makes you darker, and it is not about colour maths at all. Many preset looks ship with a vignette baked in - a soft darkening that grows toward the edges of the frame. On a landscape shot it reads as subtle. On a 9:16 selfie, where your face and shoulders reach most of the way to the edges, that same vignette lands as a dark ring on you.

Two tells give it away:

  • Turning the filter's intensity down dims the ring but never removes it, because the vignette is part of the filter - it scales with it.
  • Switching between filters does not help, because most of the catalogue carries some version of the same shading.

If your editor shows this, the honest fixes are: pick a look without a baked vignette, or grade manually and add any vignette yourself, deliberately, as its own effect. We rebuilt Zella's catalogue around exactly this rule after seeing the ring on real selfie footage: bright and neutral looks now carry zero vignette, only five deliberately dark looks shade the corners at all, and an automated test renders every look on a portrait frame and fails the build if any bright look's corners come out darker than its centre.

If it is not the colour space

Not every dull video is this bug. Worth ruling out:

  • A flat or log profile you have not graded. Footage shot flat is supposed to look dull until you grade it. That is the format working correctly.
  • Underexposure. No look adds light that was never captured. Fix the exposure first, then grade.
  • Double grading. A look on the clip and another on the export, or a preset stacked on a camera profile, compounds.
  • A phone screen at low brightness or in Low Power Mode. Judge colour on a screen you trust, at a normal brightness.

For the wider workflow, how to colour grade phone video to look cinematic covers picking and dialling a look, and how to add vignette and film grain covers the finishing pass that usually follows.

Frequently asked questions

Why do all my filters make the video look grey? Because the adjustment is almost certainly being applied in a different colour space from the one the recipe was written for. When it affects every preset equally, suspect the pipeline rather than the presets.

Is this the same as my footage being underexposed? No. Underexposure loses information at capture. This is a maths mismatch applied afterwards, and the giveaway is that the midtones sink while the highlights and blacks hold.

Will lowering the intensity fix it? It reduces the damage without fixing the cause, and it means you never actually get the look you chose.

Does this affect exports as well as preview? If the pipeline has the bug, yes, because both render through the same chain. That is different from a preview-only artifact like a torn cutout edge, which does not reach the file.

How many looks does Zella have on iPhone? 42 in the free tier, plus 3 Founder-exclusive grades for 45 in total. The Mac carries the same catalogue plus its extra "Pop" look: 43 base looks, 46 with the Founder grades.

Do I need to pay for the new looks? No. The four new archetypes are in the free tier.