OTOY Forums

Hello everyone.

I've HRD Image placed to environment and I try to understand next.
What gamma I need to set to HDR image?

It must be 1 or 2.2? What is correct value?

When I set gamma to 1, indirect lightning is very soft.
When I set gamma to 2.2 is very bright and clamped.

???

I feel like i've had the same issue too. Not sure if it's not enough dynamic range in my HDRs or if i'm setting gamma incorrectly or what.

For HDR and other linear formats as Exr32 bits and Exr16half float, you must use gamma 1.

Hi guys,
the correct Gamma for HDR images is 1.
If the shadows are soft, than the HDR has not too much exposition.
But you can correct it in Photoshop:
1. open the HDR in Photoshop 2. add an Exposure layer and lower the expsure value until the sun is still partially visible, in this case -10. 3. create an Ellipse in the position of the sun. 4. double click in the Ellipse layer and set the color as white with +10 exposure 5. remove the exposure layer and save the modified HDR.
Now you should have crisp shadow and perfect colours with Gamma 1.
ciao beppe

thanks, i'll try that with my images. If it's an interior render, i assume I would do the same technique, but just drawing a shape over the main light source/s (window, light, etc)?

Also, is there a way in photoshop to tell how much of a range there is in an HDR image I have? Like, contrast ratio numbers or anything?

Well, unfortunately, not all HDRI are created equally. Many out there suck ass. If you can not crank the Image > Adjustments > Exposure down to at least high negative teens (like -16 to -18) and still see a faint Sun (or studio lights etc), I would personally toss it.. or maybe just use it for bg or reflection mapping etc.

That is a nice tip bepeg4d.. I will have to check this out on a couple sub-par HDRs I have laying around...

itsallgood, did you ever look into HDR Light Studio? (I believe it was you I suggested that to way back) With all the product stuff you do, I would think this would be huge for you...

FrankPooleFloating wrote:Well, unfortunately, not all HDRI are created equally. Many out there suck ass. If you can not crank the Image > Adjustments > Exposure down to at least high negative teens (like -16 to -18) and still see a faint Sun (or studio lights etc), I would personally toss it.. or maybe just use it for bg or reflection mapping etc.

That is a nice tip bepeg4d.. I will have to check this out on a couple sub-par HDRs I have laying around...

itsallgood, did you ever look into HDR Light Studio? (I believe it was you I suggested that to way back) With all the product stuff you do, I would think this would be huge for you...

Thanks for mentioning the tip about about the amount of exposure range you look for in your images. That's kindof what I have been wondering

Yeah, I do own HDR Light studio. Sometimes I use it, sometimes I don't..just depends on the project. Sometimes I do like to use spherical HDRs for projects, so that's why I had some questions in this thread about issues I've run into whenever trying to use them.

Hello ! Instead of creating a new thread I might just post my relative similar question here when using HDRI+Daylight in C4D V3.
Previous v2 some users stated it's not necessary to use HDRI with Daylight and portal lights isn't needed as well to lit the scene. However for the past weeks I'm trying to get a decent lit scene with the use of DayLight+HDRI without portals however no matter what the lighting in my scenes just feels too of. I've also tried opening more rooms for my lights to enter the scene but still it's very dark and used xpresso to bind the rotation of the daylight sun the sun from my HDR but it doesn't work. Here's some screenshots from a scene I'm currently working on.

*Note: I'm not an archviz guy but starting to get into it

EDIT:
Tried switching to PMC and it's okay but it's too slow for the LV.
Maybe it's because I'm runnning on just a single 980Ti...

calus wrote:For HDR and other linear formats as Exr32 bits and Exr16half float, you must use gamma 1.

Thanks. My question was about correct gamma and right now I know which value best.
2.2 burn image and make it with very bright reflections and specular.

Well, all my render, underexposed I always use tonemapping which evens highlights and make image very natural and soft highlights.

Another question about greyscale image format. Specular, reflection and etc.

Did I understand coorect that all BW images must be 8bit Greyscale?
In octane image node I need to set gamma 1?