Why does my X3F look wrong in Lightroom?

Foveon's layered sensor is nothing like a Bayer array, and third-party converters handle it poorly. Sigma Photo Pro is free and does it properly.

What's special about the Foveon sensor?

It captures full colour at every pixel by stacking three layers, rather than interpolating from a filter mosaic. The per-pixel detail is unusually high.

How do I edit X3F elsewhere?

Process in Sigma Photo Pro and export a 16-bit TIFF, then edit that in whatever you prefer.

Host an X3F file and share it as a link

Put a Sigma Foveon raw file online at its own address — from the sensor that works unlike any other.

You can host:

Drop your X3F file here

Any other file works too — up to 25.0 MB, or 100.0 MB for a whole site

Free to use. Your X3F file is live at your-name.99helpers.site in about ten seconds.

What is a .x3f file?

X3F holds data from Sigma's Foveon sensor, which stacks three photodiode layers to capture red, green and blue at every pixel rather than interpolating from a colour filter array. The resulting detail is remarkable, and the files need Sigma's own software to get the best from them.

What people use X3F files for

Landscape and studio work on Sigma DP and SD cameras
Photography prizing per-pixel detail
Archives from Foveon-sensor bodies

What opens a X3F file

Sigma Photo Pro, free from Sigma
Lightroom, with limited Foveon support
RawTherapee, partially
No browser displays X3F

How to host a X3F file

1
Drop your X3F file in
Drag it onto the box at the top of this page, or click to choose it. Files up to 25 MB are supported, and nothing is uploaded until you publish.
2
Pick an address
Type a name and we'll tell you straight away whether it's free. That becomes the link: foveon-raw.99helpers.site
3
Publish and share
Create a free account — that step exists so the file is yours to update, replace or delete — and the link is live within seconds.

The same three steps work for any file — see how file hosting works on 99helpers.com.

What happens when someone opens the link

The file downloads. Sigma Photo Pro handles Foveon data properly; third-party converters generally do not do it justice.

Why host a X3F file instead of emailing it?

Foveon files have a devoted following who share originals to demonstrate what the sensor does. A link is easier than forum attachment limits.

Worth knowing before you publish

Use Sigma Photo Pro — third-party converters handle Foveon data poorly, and the difference is visible.
Export to TIFF from Sigma Photo Pro for editing elsewhere.
Host a JPEG alongside, since most people won't have Sigma's software.

X3F hosting questions

Why does my X3F look wrong in Lightroom?: Foveon's layered sensor is nothing like a Bayer array, and third-party converters handle it poorly. Sigma Photo Pro is free and does it properly.
What's special about the Foveon sensor?: It captures full colour at every pixel by stacking three layers, rather than interpolating from a filter mosaic. The per-pixel detail is unusually high.
How do I edit X3F elsewhere?: Process in Sigma Photo Pro and export a 16-bit TIFF, then edit that in whatever you prefer.

Put your X3F file online now

It takes about ten seconds, and you only make an account once the file is ready to go live.

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Hosting guides for related formats

Host a camera raw file Host a DNG raw photo Host a TIFF image Host a JPG photo Host a PNG image

X3F is one of over 211 formats you can host — see free file hosting for any file type for the full list, or read the hosting guides for other file types.