Disable ACES Output Transform by default in Corona Image Editor

[RecentSpacesSam]

We've noticed that when loading exr's into the Corona Image Editor they look different to when being loaded directly into Photoshop.

The cause of this is that the ACES OT is being applied to the image, even if that render had ACES OT applied in 3DS Max.

For us at least, the ideal scenario would be that the render looks the same wherever it is opened, without any additional effects/changes being applied unless the user changes them

[alexyork]

+1 ! :D

[piotrus3333]

What is the viewing transform in Photoshop?

[RecentSpacesSam]

We're currently working in Adobe 1998 in PS, but this is largely irrelevant to the above.

The issue is that any render that is loaded into the Corona Image Editor now, by default, looks different to the raw render that has been tonemapped in the VFB.

Disabling tonemapping in the CIE (or even just the ACES OT operator) brings the render back to looking how it does in Photoshop and the frame buffer in 3DS Max.

I should note that we are saving out EXR's from max rather than CXR's. Would this make a difference?

[piotrus3333]

what is the point of saving tonemapped exr renders?

adobe 1998 is indeed largely irrelevant - I was asking how are you displaying linear output from Corona in Photoshop assuming you save raw.

[maru]

@Piotrus3333 - the reported issue is that the ACES OT operator is applied to an image opened in CIE even if it wasn't used in 3ds Max. I don't think there is any need to dig deeper.

We will look into this as it sounds wrong.

Just to make sure:

The cause of this is that the ACES OT is being applied to the image, even if that render had ACES OT applied in 3DS Max.

This is a typo and it should be:
"The cause of this is that the ACES OT is being applied to the image, even if that render had no ACES OT applied in 3DS Max."

right?

[piotrus3333]

@Piotrus3333 - the reported issue is that the ACES OT operator is applied to an image opened in CIE even if it wasn't used in 3ds Max. I don't think there is any need to dig deeper.

We will look into this as it sounds wrong.

Just to make sure:

The cause of this is that the ACES OT is being applied to the image, even if that render had ACES OT applied in 3DS Max.

This is a typo and it should be:
"The cause of this is that the ACES OT is being applied to the image, even if that render had no ACES OT applied in 3DS Max."

right?

it rather looks like aces ot applied twice.
but sure, no more digging.

[RecentSpacesSam]

@maru Correct!

Apologies for the typo. To summarise:
Any image (regardless as to whether it was rendered with corona) looks different in the CIE with the default CIE settings, because the ACES OT operator is affecting the image


Separately:
Did some testing today and .cxr's do not have the same issue, presumably because they are being saved with no tone mapping applied but the metadata applies the correct operators in CIE?


Edit: this is all in 9.1

[TomG]

Right on the second point, it saves everything as default and applies tone mapping and lightmix in the CIE itself (loading those parameters from the VFB through extra metadata). You can save to CXR and rename to EXR to get a standard EXR file (which should be untouched by tone mapping as it wasn't applied), as the metadata just gets ignored then, btw. This would give the option of using the CIE on the CXR version, and renaming it or a copy of it to EXR to open in some other application like Photoshop or Fusion to do all the tone mapping there.

[RecentSpacesSam]

@TomG Thanks for confirming!

Reason I ask is that we've recently taking to network rendering our high res images as tiles, but unfortunately this breaks Bloom & Glare (through no fault of Corona) so CXR's seem to be the workaround that we need :)

[TomG]

Happy it helps! CXR is "two worlds for the price of one" in my opinion lol.

[NazarVitkovskyi]

On Wrike: (Internal ID=1095091693)

[rowmanns]

Hi,

Just informing you that unfortunately, we cannot do anything about this. We don't have any control over what data is saved into the exr, therefore when loaded into the CIE the default TM pipeline will be applied.

As stated above, we would advise using CXRs in this situation.

Cheers,

Rowan