Why does a JPEG look washed out after saving it as OpenEXR in Preview?
Asked 5/5/2017
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On macOS Sierra, I opened a JPEG in Preview and saved it as OpenEXR (8 bits per channel). The EXR looks washed out compared with the original JPEG. Why does this happen, and how can I export or view an OpenEXR so it looks correct?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
9y ago
2 Answers
1
OpenEXR stores its pixels in linear RGB, whereas JPG stores its pixels in a gamma-corrected RGB. (Technically JPG converts this to Y`CbCr before compression, but that's irrelevant to this question.) If you go to the "Tools" menu and choose "Adjust Color…" it will bring up the color adjustment window. You can adjust the gamma using the midpoint just below the histogram. If you move it to the right you should be able to get it back to the state you want.
Another way to show it how you want to see it is to go to the "View" menu and select "Soft Proof with Profile…" and choose "sRGB IEC61966-2.1".
Originally by user22895. Source · Licensed CC BY-SA 4.0
user22895
9y ago
0
Generated from our catalog & community — verify before relying on it.
This is mainly a color/gamma issue. JPEGs are typically stored in a gamma-corrected color space such as sRGB, while OpenEXR is designed around linear RGB data. If Preview saves or displays the EXR as linear without applying the expected display transform, the image will appear flat or washed out.
In Preview, you can compensate when viewing by either:
- using Tools > Adjust Color… and moving the gamma/midpoint control to the right, or
- using View > Soft Proof with Profile… and choosing “sRGB IEC61966-2.1”.
So the file is not necessarily ruined; it’s being shown with different tone mapping/gamma than the JPEG. To get an EXR that appears “normal,” you need to apply the proper display/profile conversion for viewing, or export from software that correctly manages the conversion between sRGB-style JPEG data and linear EXR data.
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