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ErikKeller

Is it possible to increase Exposure in a masked region to create a 32-bit HDRI?

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Hi,

I searched quite a bit, but couldn't find a way to partially modify the exposure in a 32-bit image to create a, none tone mapped, HDRI to be used as lighting in 3d software.

 

In a nutshell: I want to create a 32-bit HDRI and increase the exposure within masked areas to different values, pretty much like the Exposure control in Photoshop.

The exposure adjustment layer would require me to paint the influence mask after applying, but it does not seem to be able to increase the exposure value in a way necessary for  IB lighting.

 

Using the Develop Persona allows me to increase the exposure value for the whole image, but requires me to calculate color values in advance to, e.g. create a grey background with "lights".

 

Am I missing something or should this go into a feature request?

 

TIA,

Erik

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Hi Erik,

 

Welcome to the forum. 

 

You can select parts of the image, then go to Layer>Adjustment Layer>Exposure and this will only affect the selected area. 

 

Thanks,

Gabe. Exposure.thumb.gif.8f850cf0c659a24bb6cd5704b1969213.gif

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Thanks, I'll try this (again). Maybe I missed something the first time. It seemed to me, that the luminance couldn't be pushed more than it could be pushed in a non-32-bit image.

 

Thanks again,

Erik

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55 minutes ago, ErikKeller said:

Thanks, I'll try this (again). Maybe I missed something the first time. It seemed to me, that the luminance couldn't be pushed more than it could be pushed in a non-32-bit image.

 

Thanks again,

Erik

 

No, it can't. If the information isn't in there there's no way you can push it further.


Andrew
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Win10 x64 AMD Threadripper 1950x, 64GB, 512GB M.2 PCIe NVMe SSD + 2TB, dual GTX 1080ti
Dual Monitor Dell Ultra HD 4k P2715Q 27-Inch

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@verysame Actually, it can. I just tried. But there is a lot of trial and error involved.

 

You have to start out with either a non-tonemapped HDR or create a RGB/32 document and start from scratch.

 

The easiest way would be a control to increase the luminance within a masked region, obviously.

 

@GabrielM thanks again. I guess I messed up during the first experiments.

 

Thanks to all,

Erik

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@ErikKeller I must have misunderstood your question, I thought you were asking if it is possible to increase the exposure in a non-32 bit image in order to get an HDR image.

That said, watch out for the 32-bit screen redraw issue. You might get, depending on your workflow, some black splotches. A simple exposure adjustment should be fine though.


Andrew
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Win10 x64 AMD Threadripper 1950x, 64GB, 512GB M.2 PCIe NVMe SSD + 2TB, dual GTX 1080ti
Dual Monitor Dell Ultra HD 4k P2715Q 27-Inch

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On 5/12/2018 at 8:07 PM, verysame said:

@ErikKeller I must have misunderstood your question, I thought you were asking if it is possible to increase the exposure in a non-32 bit image in order to get an HDR image.

That said, watch out for the 32-bit screen redraw issue. You might get, depending on your workflow, some black splotches. A simple exposure adjustment should be fine though.

 

@verysame Ah, I see. No worries.

Regarding increasing exposure in a non-32-bit image. Even this is possible, it's just a lot of trial and error, though. If I find a "stable method", I probably post a video.

 

Thanks for the warning regarding the redraw issue.

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