I made some custom HDR skies today. When I did my test renders the light intensity was waaaaaaay off. After some poking around, I found the problem. Photostop CC(2015) is reading and saving EXR files wrong somehow. Photoshop is clamping everything over +16.41 intensity down to +16.41. I’ll post some of my test results bellow so you can see what I’m talking about. My workaround right now is to save stuff as .hdr. I just wanted to give you guys a heads-up so you don’t clamp your images, save as .hdr from Photoshop.
I have tried every exr compression method, same result.
For this test I made a HDR of Corona Sun/Sky, 7070x3535px.
Actually I think this is related or the same as the issue I posted the other week.
Are you using Contrast > 1.0 in your Tone Mapping? Doesn’t matter if using CoronaCameraMod or just the VFB. Because if you are, it will clamp your image no matter if you save to EXR 16/32 whatever.
I always render 1-1 linear in framebuffer and use tone mapping as my last node. But as you can see from the color picker images above, this is not Corona related.
When I open a fresh .exr/.hdr the sun is +20 intensity. After a ctrl+s the .hdr is still +20 intensity and .exr is +16 intensity.
I even did a full format on one of my PCs and installed Photoshop, same result. It’s like Photoshop is corrupting everything above +16, because some programs read the new +16 value as 0.
I have uploaded a test for you guys. Open that .hdr, save it as .exr, close everything in Photosop and open the .exr again. The +20 value should be +16. Test.hdr (30.1 KB)
Yes, HDRs in Photoshop are handled differently than EXRs, up to a point where you simply can’t paint over a hot pixel in both positive and negative values, it’ll simply stay there and keep it’s value no matter how hard you try to paint over it. As for their support, I guess HDR images are not high on their list.
Have you tried with all of the available EXR save options - integer, full and half float?
I just made a post over at Adobe, man is that site a mess to navigate.
Could you guys please try to resave the test.hdr image I uploaded in my last post, and see what the results are ?
The image was made in Photoshop, so we don’t drag Corona into this.
It’s not only photoshop’s problem. I did quick test with Picturenaut and it clips dynamic range when saving to exr too. Maybe it saves to half float rather than full float?
