# Vignetting mask

**URL:** <https://discourse.radiance-online.org/t/vignetting-mask/6138>\
**Category:** hdri\
**Created:** [January 19, 2023, 4:42am UTC](https://discourse.radiance-online.org/t/vignetting-mask/6138 "2023-01-19T04:42:30Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Guanzhou\_Ji](https://discourse.radiance-online.org/letter_avatar_proxy/v4/letter/g/ce7236/32.png) [@Guanzhou\_Ji](https://discourse.radiance-online.org/u/Guanzhou_Ji)\
**Post date:** [January 19, 2023, 4:42am UTC](https://discourse.radiance-online.org/t/vignetting-mask/6138/1 "2023-01-19T04:42:31Z")

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Dear community,

I created a vignetting mask (mask.png) for my own fisheye lens.

 ![mask](https://discourse.radiance-online.org/uploads/default/original/2X/c/c94cacab1a7bf2beb34e0b2f3f207c42bec24e58.jpeg)

To correct vignetting effect for my captured fisheye hdr, I simply changed the filename from (mask.png) into (mask.hdr).

Then I applied the ‘mask.hdr’ into ‘image\_in.hdr’, and the error is bad picture size; the image dimensions for both hdr are the same.

 ![Screenshot 2023-01-18 232320](https://discourse.radiance-online.org/uploads/default/original/2X/a/a20c4c4062f11012f37bfc848f3aef98d3922675.png)

I assume something wrong when I created ‘mask.hdr’ file?

Thanks!

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**Author:** ![Greg\_Ward](https://discourse.radiance-online.org/user_avatar/discourse.radiance-online.org/greg_ward/32/471_2.png) [@Greg\_Ward](https://discourse.radiance-online.org/u/Greg_Ward)\
**Post date:** [January 19, 2023, 4:59am UTC](https://discourse.radiance-online.org/t/vignetting-mask/6138/2 "2023-01-19T04:59:46Z")

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Changing the file suffix from “.png” to “.hdr” doesn’t change the file format or contents. You need to use Photoshop or similar to convert the file, as PNG is not supported by any of the Radiance converters. (I’ve looked into it, and the PNG library is a nightmare.) There are converters for TIFF, TGA, BMP, and PPM.

Cheers,  
-Greg