How to mix a jpeg background image with a 3D scene generated using Filmic Blender?

Question

I want to compose 3D-model over image, and I use filmic to get more suitable result. But I want the background image to remain in the original colors. So I try to use this setting:

but it haven't setting "look" ("high contrast", "low contrast", ets..) here, so color changes..

How to solve this?

Of course, I can save my render and compose it with jpg-image in different place - no problem here, but my question is about how to make it in place. It will give ability to control colors in filmic color space and see the results immediately.

UPD: image is from image node:

UPD2:

you can't really convert a display referred image to the scene referred domain; the information has been permanently lost

Ok, but how to make the colors at the output looks close to the original?

UPD3:

This filmic version is from daily build.

Answer 1

Since Blender 3.3 :

We now have a Filmic sRGB color space for image nodes so it's now possible to superimpose a Filmic 3D render to an sRGB image.

Here's a render with sRGB everywhere:

And here it is with Filmic. Note how the background image is unaffected, yet the Suzanne heads clearly use Filmic (the blue one is here to demonstrate the desaturation of bright surfaces that Filmic applies):

Note:

This works for image nodes in both the compositor and the shader node editor, so you can get the composite render directly in the viewport.

Also, since 3.4 :

If you change the exposure, you can keep the background image (or any emission shader) unaffected by the exposure change with this simple node setup :

Answer 2

Some good information in the other answers, but I am not sure they specifically address your interchange needs.

So, to start, I would encourage every reader of this to use full or half EXR. That will preserve the image state, and all of the data.

If you can't use EXR, and need to store in a device referred / display referred format, you will require at least 10-12 bit depth at a minimum for a log encoded image. Given that DPX support in Blender is horrifically broken, I would encourage you to choose 16 bit TIFF, and save with "Filmic Log Encoding Base", and no contrast curve.

You are welcome to preview the work using the curve, but if you intend to save the image for further work and manipulation, and you are unable to utilise half float (16 bit) or full float (32 bit) EXRs, a pure Filmic log encoded 16 bit TIFF will preserve a majority of the data for further manipulation. Remember that one cannot save a log encoded image at 8 bits per channel and recover scene referred values adequately.

When loading the images within Blender, select "Filmic Log Encoding Base" for your TIFF images at 16 bits per channel. This will assert that the imagery is transferred back to the scene referred domain correctly. For EXRs, the default "Linear" is correct.

Hope this helps.

PS: Heed the advice and download Filmic from the official GitHub. If you see ACES in there, it is wrong.

Answer 3

I'll try to answer simply but even for me it's not. But what you try to do isn't possible. (see the edit 1 for the answer of your problem)

1st, prerequisites:
In our world light is linear, but we didn't see it linear, the eyes make it looks with more contrast (what we can call a transfer curve).
Your display (let's say a computer screen) have it's own transfer curve (for technical historical reason), so to see a picture close to what we see in real life (a linear light interpret non linear by the eyes) we need to bake a transfer curve "inverse" of the display one to bring the image a linear signal to the eyes.
At this stage it's a bit confusing, let's make it simple:

Real life: Linear light --> non linear interpretation by the eyes

sRGB image: non linear (transfer curve of sRGB) --> linear ("inverse" transfer curve by the screen) --> non linear interpretation by the eyes.

CG: Scene referred linear image (what Cycles calculate internally)--> non linear (ex: filmic+high contrast transfer curve) --> linear ("inverse" transfer curve by the screen) --> non linear interpretation by the eyes.

It's a bit simplified but what's important to understand here is that the eyes need to recieve a linear image, like in real life eyes recieve linear light but we don't see it linear.
One more important things is that each of the above have their own transfer curves (eyes, screen, filmic, sRGB, APN, smartphone... they are all different).

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If you set up a color space to filmic for an image in 8bits sRGB .jpg that you don't know how it was manipulated, you try to see informations that were lost in the compression + you're mixing transfer curves.

You must look filmic in two parts.
1st, the filmic itself, that is a LUT which compress values to be in 0/1 range in a logarithmic way (transfer curve). So, the end result is a nonlinear image.
2nd, the contrast looks which modify the transfer curve shape.
There is one more caracteristic with filmic, the desaturation of the high value colors.

I'll see if I've made mistakes or forgot something in what I've said, and will correct them if it's the case. Don't hesitate to tell me if I'm wrong or need more informations.

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Edit 1: Sorry I've understand a bit more your problem and have more infos.

When you try to compose your image with your final render you need to remember that filmic in the color management is aim for linear scene referred images and is applied at the very end of the chain, so your image that is composed with the linear render will have filmic conversion too. But your image is an 8bits sRGB .jpg and must be threat as a sRGB EOTF.

What you need to do is save your render with filmic and all compositing but without the background, and after that compose your render with the background image both in sRGB for image colorspace and color management view in sRGB, no more color transformation at this stage since you are in 8bits.

This is the problem when you work with both linear scene referred data and display non linear data.

Hope I've all understood this time.

Answer 4

You seem to have an older version of the Filmic LUTs. You can update those from the github page - https://github.com/sobotka/filmic-blender

That won't resolve the conflict however. The Filmic LUTs will linearise the render data, but the image is (probably) sRGB with a 2.2 gamma curve.

To match the render you should composite with a similarly linear image. If you made the photograph you can do that relatively easily. If not it will be difficult to match the wide dynamic range of the render(scene referred data) with the non linear, clamped 0 - 1 sRGB image (display referred data).

Do keep in mind though, when compositing with the linear data (image and render) you will be able to work with all the advantages of the Filmic LUTs, so your final image may still look a little different.