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Difference in Colors when switching from 32-bits to 16bits in Photoshop

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Message 1 of 7
Anonymous
1007 Views, 6 Replies

Difference in Colors when switching from 32-bits to 16bits in Photoshop

I'm doing simple render in Arnold and exporting in a multiple EXR file in Maya 2018

I'm opening it in Photoshop and blend in "Linear Dodge(add) over the Diffuse_Direct the :Diffuse_Indirect+Specular_Indirect+Specular_Direct. (sRGB IEC61966-2.1 in 32 bits)
I got the same result as in the Arnorld render view, but as soon as I'm switching in 16 Bits my image get overblast and I don't understand why.
I want to switch in 16 bit order to have more edit over the layers.
In Arnold i'm using the Maya Color Space sRGB, my textures (normal+roughness) are in Raw and my Basecolors are in sRGB in rendering space and view transform

6 REPLIES 6
Message 2 of 7
Anonymous
in reply to: Anonymous

I’m using EXR I/O in photoshop to import all the layers.

Message 3 of 7
brian_Foley
in reply to: Anonymous

Hi @Darkalex09 Darkalex09

To understand what is happening go to the info pallette and click and hover over the color picker. You will see that:

32 bit is 0.0-1.0 float

16 bit is 0-32768 integer

8 bit is 0-255 Integer

2982-colorpicker.jpg

When you convert to 8 or 16 the info is converted to integer and the ‘linear dodge (add)’ calculation does not work correctly (overblast)

You can try this:

Open your EXR

Edit - Color Settings - Select Custom RGB in the working spaces section.

change the gamma to 1 with Adobe RGB or HDTV as primaries (probably want to save the profile so you can use it again)

This will change the gamma so ‘linear dodge (add)’ will behave the way it does in 32 bit.

Now you should be able to convert to 16 while maintaining the color. It is best to stay in 16 bit until you flatten the linear dodge add layers.

Here is a link to creating the profile

It’s ancient but it still works.

http://fnordware.blogspot.com/2008/05/making-linear-icc-profile.html

Make sure you switch back to sRGB when you are done.

I don’t use AE to often but I would assume you can change the profile there as well.

Hope this helps.

Message 4 of 7
Anonymous
in reply to: Anonymous

Thank I'm gonna try this but I'm not using After Effect, I'm using Photoshop

Message 5 of 7
brian_Foley
in reply to: Anonymous

It is for photoshop.

Message 6 of 7
Anonymous
in reply to: Anonymous

I did some quick tests and it seems to work, but I will do more tests tonight.
Thank you for that fast answer.

Message 7 of 7
Anonymous
in reply to: Anonymous

After a lot of tests, there is one more step to do:
-After going back to sRGB you need to convert your file and use "Convert to Color Profile" in Photoshop, otherwise when you'll save the file it will be still in "Linear" profile mode even if you changed back the Color Profile in Photoshop in sRGB. Hope it make sense.
PS: if you need to add another file (in sRGB) into your EXR layers, you need to convert the sRGB file into the correct colort profile (liner) vice and versa with the same option "convert to color Profile"

Anyway thanks for your answer, it had really helped me.

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