How to rescue a cutout that lost its transparency

Last updated 2026-09-04 · 7 min read

What is the short version?

A cutout that arrives as a solid rectangle has two possible explanations that look identical: the transparency was never written, or it is there and whatever opened the file ignored it. The fix is completely different for each.

1. Go to Vizard Agent with the cutout file.
2. Say it composites as a solid box, or that it has a halo.
3. Let it check whether the alpha exists before anything is redone.

What do you need before you start?

The actual file, not a picture of it. A screenshot of the problem tells Vizard Agent nothing useful here — the entire question is what is inside the container, and the only way to answer that is to decode the file and look at the planes it holds.

• The cutout. The file itself.
• What you see. A box, a halo, or hard edges.
• What made it. The tool or export, if you know.
• Where it is going. Some pipelines drop alpha on import.
• The original source, if you have it. A rebuild may be cheaper.

What do you type into Vizard Agent?

Describe the symptom rather than diagnosing it. "The transparency is missing" is a conclusion, and it is wrong about half the time — the more useful thing to say is what the picture actually does when you put it over a background.

Prompt

Variants worth knowing:

• "Check before regenerating." Saves a rebuild that fixes nothing.
• "There is a halo." A different fault; alpha exists but is soft.
• "Show me the matte." The fastest way to see the truth.

What does Vizard Agent actually do?

Here is the order Vizard Agent worked in on a real cutout that would not composite. Steps two to five are a diagnosis, and none of them change the file — they establish what is actually wrong first.

1. Checks the cutout's alpha and measures the subject's position.
2. Inspects the file's real streams and format, not its extension.
3. Extracts a frame over a checkerboard to see the matte.
4. Views the cutout over magenta to check the edges.
5. Separates the colour and alpha planes to see what is really there.
6. Views the colour plane on its own.
7. Extracts frames with output seeking and checks the alpha again.
8. Reads the background-removal log and scans the alpha across the clip.
9. Checks whether the decoder exposes the alpha plane at all.
10. Does a clean no-seek decode of specific frames.
11. Tests a ProRes conversion to recover the matte.
12. Re-runs the background removal and checks the output.
13. Tries the alpha-aware decoder rather than the default one.
14. Verifies the recovered alpha at three timestamps over green.
15. Tightens the alpha edge to remove the halo.
16. Views the tightened composite to confirm.

Step nine is the one that saves the day, and it is the least obvious. A file can carry a perfectly good alpha channel that the default decoder silently discards — so the picture is fine and the reader is wrong. Regenerating the cutout in that situation produces another perfect file that also composites as a rectangle.

Steps three and four are how that gets established quickly. Looking at a matte over a checkerboard, and then over a saturated colour, tells you in two frames what a log file will not.

What does the result look like?

A cutout that composites cleanly over whatever you put behind it, with the edge tightened by Vizard Agent so there is no halo of the old background clinging around the subject's hair and shoulders, and no hard cut-out line where the key was too aggressive.

Along with it you get the answer to which problem you had. That matters for next time — a decoder problem means your export settings were fine, and a missing-alpha problem means they were not.

When does this not work well?

Some formats cannot carry transparency at all, and a matte that was never written in the first place cannot be recovered from the colour pixels by Vizard Agent or anyone else. There is also a hard limit to what edge tightening achieves when the original key was poor.

• Formats without an alpha channel. Nothing to recover.
• A flattened export. The background is baked into the colour.
• Very soft or hairy edges. Tightening costs detail.
• Motion blur at the edges. The matte is genuinely ambiguous there.
• Heavy compression. Alpha compresses badly and shows it.

How do you fix a result that came back wrong?

Say what you can see now rather than what you think is wrong. Vizard Agent keeps the decoded matte, the plane separation and the edge settings from the first pass, so a halo or a hard edge becomes an adjustment to the existing alpha rather than a second background removal from scratch.

• "There is still a halo." The edge tightened further.
• "It is cutting into her hair." Loosened; detail restored.
• "It flickers." The matte checked frame by frame.
• "My editor still sees a box." Delivered in a format that tool decodes.

How does Vizard Agent compare to doing it yourself?

By hand the temptation is to regenerate the cutout, because that is the obvious move and it sometimes works. When the problem is on the decoding side, you can do that three times and get three identical rectangles.

Common questions

Why does it look solid if the alpha is there? Because the default decoder can drop it silently. Vizard Agent tests for that.

Can it recover alpha from a flat file? No. If the background is baked into the colour, Vizard Agent has to re-key it.

What formats carry transparency? Several, and not all editors read all of them. Vizard Agent will deliver one yours reads.

Can it just re-cut the subject out? Yes, and sometimes that is right — but Vizard Agent checks the first file first.

What is the halo? Old background clinging to the edge. Vizard Agent tightens the matte to remove it.

Will tightening lose hair detail? It can. Vizard Agent shows you the trade-off on real frames.

Can it check a whole clip? Yes. Vizard Agent scans the alpha across the duration, not just one frame.

Does the colour plane matter? Yes. Sometimes the colour is fine and only the alpha is broken.

What if my editor still won't read it? Say which editor and Vizard Agent delivers a format it decodes.

Can it deliver a green screen instead? Yes. Vizard Agent will, if that is easier for your pipeline.

Does compression affect this? Yes. Alpha compresses badly, and Vizard Agent will say when that is the cause.

Can it fix a flickering matte? Often. Vizard Agent checks it frame by frame rather than on stills.

How long does the check take? Minutes. Far less than having Vizard Agent rebuild the cutout.

Why check before regenerating? Because if the alpha was always there, a new file will have exactly the same problem and you will have paid for it twice.