To avoid the problems that PNG has with fire Transparency, I exported the images in EXR format, but when I compare them to the PNG counterpart, the colours in the EXR image are way to blown out.
Why and how can I correct for that?
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2$\begingroup$ Where are you viewing and comparing the images? It could be that the software doesn't handle the OpenEXR file properly. $\endgroup$– Robert GützkowCommented Apr 10, 2020 at 17:18
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$\begingroup$ I am viewing them in davinci Resolve $\endgroup$– Phönix 64Commented Apr 10, 2020 at 18:06
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1 Answer
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Explanation first:
PNGs can't handle pixels that are emissive and transparent at the same time because PNG does not support associated alpha transparency.
You are on the right track using EXR, what you need to understand is that EXRs are exported as linear information (meaning no "gamma curves" are applied to make them display nicely on a monitor). The images on EXR format are not constricted by the limits of Display Referred, with none of the color transforms set by the color management. (visit this link for a deeper explanation). Think of EXR images as exact copies of the render layer with all of the brightness and color, which might exceed the limits of what the monitor can display.
An attempt to answer:
EXR have to undergo some color transform before they can be displayed nicely on the screen. If you import them onto other software (like photoshop) they need to be interpreted as linear before they can be displayed,and probably scaled so that they fit within the values used by the display device. If you do the compositing in blender, the EXRs should have no problem. Please add information on how you are viewing them and what you want to do with the image.
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$\begingroup$ I am viewing the EXR images in Davinci Resolve because at the end I want to make an animation with these images. $\endgroup$ Commented Apr 10, 2020 at 18:07
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2$\begingroup$ Looks to me that the values of the EXR exceed the limits of display referred, so in Resolve, just scale the data with the "gain" control in the color section. Or you might want to try using the filmic LUTs in resolve: github.com/sobotka/filmic-resolve $\endgroup$– susuCommented Apr 10, 2020 at 20:30
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$\begingroup$ Great answer. The free edition of Resolve could be coaxed to transform EXR data properly, but at a quantisation cost. Resolve Studio would permit DCTLs, which would be higher quality. Best advice is a sixteen bit integer Filmic Log TIFF with an appropriate contrast LUT applied. Here’s a helper for those interested: docs.google.com/spreadsheets/d/… and of course the branch susu linked to has a turnkey solution. $\endgroup$– troy_sCommented Apr 10, 2020 at 21:17
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$\begingroup$ Thank you all, I finally understand the EXR format and my problem is solved :) $\endgroup$ Commented Apr 11, 2020 at 1:01
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$\begingroup$ @JachymMichal Thank you, but I have one more question. Today I tried the answer from but the EXR image locks weird after I implemented the filmic LUT's: imgur.com/a/a8xzww5 $\endgroup$ Commented Apr 11, 2020 at 16:59