Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Image Box Studios on 2015-03-20, 07:15:58
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Hi to everyone....May be i am asking a stupid question here but i don't understand. Actually i save render output in exr 32 bit format every time. i call the 32 bit exr image into Photoshop and do some post work. and i want to save the image in jpeg format from 32 bit exr but with 32 bit exr mode , i am not getting the option .jpeg because of 32 bit exr mode. and if i changed the 32 bit exr into 16 bit exr ,the option jpeg now available...now the problem is when i changed 32 bit to 16 bit ,the image depth has been changed. and my image lost some details on foliage/trees and on reflected surfaces/objects....is there any way to save .jpeg format directly from 32 exr.
Thank you in advance.
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No, jpeg format supports 8bits only.
32 or 16 bit depth needed for image editing only. For viewing stick to 8 bits.
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I always converting the 32bit exr to 16bits tiff and after to jpg. Ofcourse, you will lose so much details, but the clients normaly never see the diffrenties. For any case I send the 16bit tif and the 8bit jpg for my clients. There is no occasion to not to do that...
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If you convert 32 bit into 16 or 8 bit channels you have to use the "gamma\exposure" method and leave those as defaults. In that case your image doesn't get color corrected. When working with layers in photoshop just press the "don't merge" option and your tone mapping will stay the same.
Don't know why it's like that (I work with CS6) so it might be different with the newer versions.
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Not flattening the image when converting from 32bpc to 16 or 8 bits may result in differences for blending modes (add/subtract etc). Actually, there's almost no point in working with 32bits in PS except when you absolutely need to tone down exposure or extreme level corrections. My advice would be to convert to 16 bits right away and then do your corrections, it'll still give you a greater control than 8 bits and you don't run into the pitfalls of different output from the 32 bits when using blending modes with your layers.
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Not flattening the image when converting from 32bpc to 16 or 8 bits may result in differences for blending modes (add/subtract etc). Actually, there's almost no point in working with 32bits in PS except when you absolutely need to tone down exposure or extreme level corrections. My advice would be to convert to 16 bits right away and then do your corrections, it'll still give you a greater control than 8 bits and you don't run into the pitfalls of different output from the 32 bits when using blending modes with your layers.
My thought exactly, thanks for writing it down :)
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I always converting the 32bit exr to 16bits tiff and after to jpg. Ofcourse, you will lose so much details, but the clients normaly never see the diffrenties. For any case I send the 16bit tif and the 8bit jpg for my clients. There is no occasion to not to do that...
Hi...yeah i know but if every time we convert 32bit to 16 bit then why we save the output in 32 bit exr,why not in 16 bit?
Anyway thank you.
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If you convert 32 bit into 16 or 8 bit channels you have to use the "gamma\exposure" method and leave those as defaults. In that case your image doesn't get color corrected. When working with layers in photoshop just press the "don't merge" option and your tone mapping will stay the same.
Don't know why it's like that (I work with CS6) so it might be different with the newer versions.
Hi fellazb....i follow this method every time but don't merge option change the image depth too.
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Not flattening the image when converting from 32bpc to 16 or 8 bits may result in differences for blending modes (add/subtract etc). Actually, there's almost no point in working with 32bits in PS except when you absolutely need to tone down exposure or extreme level corrections. My advice would be to convert to 16 bits right away and then do your corrections, it'll still give you a greater control than 8 bits and you don't run into the pitfalls of different output from the 32 bits when using blending modes with your layers.
My thought exactly, thanks for writing it down :)
Hi...thank you...so your advice is , convert 32 to 16 bit before any post work and always use don't merge option when converting 32 bit to 16 bit. but i have a question, actually i use Arion fx for post in cs5 and arion fx works well with 32 bit. i mean to say that i use 32 bit exr with Arion fx and do some post in arion fx and after that i convert 32 bit to 16 bit. so what do you think, should i use 32 bit or 16 bit with Arion fx.
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Althoug ArionFX works on 16 bits it is designed for 32 bits and you should always use 32 bit for it to work properly. So convert to 16 bits afterwards, yes. By the way, ArionFX will output a low dynamic image, it will still be in 32 bits but it is clamped after any action in ArionFX.
The important part is to avoid layer blending other than 'normal' if you want to switch to 16 or 8 bits without visible differences. Or, to be fully flexible, convert to 16 bits before you do your corrections.
The reason is that the math behind the blending modes produces different results and there's no way to make it look identical without flattening the image.
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+ Everything that Pokoy said.
Actually, maybe we should write some guide because almost every week someone asks the same question over and over and it makes me wonder..do most people actually understand the whole .exr/32bit output reasons ? Or they just keep using what they saw and probably keep making redundant choice or mistakes somewhere down the path.
I wrote few bits here and there but it's too scattered on the forum.
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+ Everything that Pokoy said.
Actually, maybe we should write some guide because almost every week someone asks the same question over and over and it makes me wonder..do most people actually understand the whole .exr/32bit output reasons ? Or they just keep using what they saw and probably keep making redundant choice or mistakes somewhere down the path.
I wrote few bits here and there but it's too scattered on the forum.
I can write something about OpenEXR + ArionFX workflow on this weekend.
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+ Everything that Pokoy said.
Actually, maybe we should write some guide because almost every week someone asks the same question over and over and it makes me wonder..do most people actually understand the whole .exr/32bit output reasons ? Or they just keep using what they saw and probably keep making redundant choice or mistakes somewhere down the path.
I wrote few bits here and there but it's too scattered on the forum.
I can write something about OpenEXR + ArionFX workflow on this weekend.
Thank you Pokoy.
Thank you very much Nekrobul, Please write some tips. we will wait for your article on 32 bit exr+Arion fx workflow.
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I wonder is there a reason to save in full float ever? No matter how hard i tried to find a difference between HF and FF, i couldn't find one, except file size. Even when there's sun directly visible.
Also i was surprized that there's a big difference at what exposure file is saved in 32bit. I always thought it is no matter.
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I wonder is there a reason to save in full float ever? No matter how hard i tried to find a difference between HF and FF, i couldn't find one, except file size. Even when there's sun directly visible.
Also i was surprized that there's a big difference at what exposure file is saved in 32bit. I always thought it is no matter.
Wait, we're not talking about HF/FF exrs but the bit depth in Photoshop. Let's not confuse us ;)
(I also always save with HF and never saw any drawbacks.)
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Just testd HF\FF absolutley no difference (atleast noticible)
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Regarding 32 vs 16 bit floating-point difference worth it for 3D:
Short answer: No.
Long answer:
30 f-stops (25 - 2), with an additional 10 f-stops with reduced precision at the low end (denormals).
http://www.openexr.com/about.html
If it wasn't for Ondra writting that half-float might clamp up sun, which is analytical light thus it might create the intensity but almost everything else probably can't. Even then, 30 stops is a lot,
compare to 16 which most high-end aftermarket HDRi like CG-Source have.
Deadclown's reponse intrigued me, I didn't even think it mattered that much outside of color post-production. Will test on Z-depth myself
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There are situations where you need 32 bit for zdepth and or World position passes. Since those have tiny value differences it's crucial to have the full precision (sometimes even depending on the scale and world units of your shot/scene).
The average color passes don't need 32 bit (diffuse, reflection, lighting, ...), for "technical" passes however it's sometimes better to chose higher precision.
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Answering on Juraj's edit ;)
You won't probably see a difference if you don't know how to force it. In "normal" zdepth compositing workflows there is practically no problem. There maaay be a minor difference in dof but that's not what I meant.
I, for example, use world position data to displace cards in 3d space and do some kind of 3d compositing inside Fusion (you can either render out a wpp or generate the position data using a camera matrix and a high precision zdepth pass).
If you have a small scene (some centimeres in size) and still have a system unit of centimetes, value differences in world position data can be extremely small. In such cases you see the typical low-precision artifacts in displacements.
It can also occur on larger scenes where values exceed the 16 bit float maximum (had this a number of times) and your world position data becomes clamped and thus useless.
Those cases may rather be rare and pretty predictable but I depends on the workflow and stuff you work on.
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Interesting, completely out of my world but good to know :- ) VFX compositing is very much magic to me.
But reassuring that Photoshop simpletons can keep on conserving harddisk space.
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Thanks for explanation, now i can forget about full float whatsoever :]
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Thanks from me as well :)
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I personally save as 32-bit EXR/Tiff just to have those originals in case of a high dynamic range render (exterior+interior, etc). Load up the file in PS, do any exposure corrections or highlight/shadow recovery I need and then use 16BPC for final compositing. The end result is saved at 8BPC JPEG or PNG.
That's how I do it personally.
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Thank you everyone for their supportive comments on this topic.