Hello Everyone,
I was testing the scenecapture2D with render target and a material on a plane;
Here is the result :
As you can see, it’s a bit yellow/orange/“Grand Canyon” color,
and… I have no idea why.
PS : First Time using material, “camera”, render etc.
I am a programmer looking outside the code 
Render targets were invented in the 70’s ( just kidding ).
There are a lot of options in the render target construction. I seem to recall the default render type isn’t helpful 
Maybe try this
I did some test with the SceneCapture parameters :
(Only showing this two screenshots because the other parameters did not do much difference OR way too much difference)
With the Final Color (also tested with the others Capture Source), and without the eye Adaptation (wich make the view like a Flash nade in CS… dont know why),
It’s better.
There is still the “warm” color but it’s lighter.
Even as a “kidding” mention, do you perhaps have another way doing this ?
At first I was hoping to “get the video flux” of a cine/camera and put it on a material, but the Internet is yelling to use SceneCapture 
EDIT : Not a solution !
So,
I managed to figured out something :
The plane (or the mat… Something 
) is affected by the Sky/Sun/Exterior Light.
I put the plane in a room with a bright white light and it was not “warm”/orange…
I will probably create another QA if I have another question about what I am doing (still blurry)
Thanks for your answer @ClockworkOcean 
(Still interested by the question " do you perhaps have another way doing this ? ")
Have a nice day Everyone 
You’re just dropping the texture on a plane after rendering it? Maybe put it in a material and set it to ‘unlit’. ( just use the emissive pin ).
I’m afraid it is quite a lot of fiddling about
I uncheck the “solution” in the forum;
The “solution” was not a good one. 
And, can’t be a solution.
It was bright (not warm) only because I build lighting when there was only light in a room.
SceneCapture linked to a Render Target;
A Material created based on the render target (right click : create Material)
And a instance material on the plane.
The “unlit” turn the material black.
The preview of the material is great :
Is it possible to, put a material on “not affected by the sky/sun light” ? 
Or make the material “absolute” / above every light/rendering effects
Yes, like I say, unlit
OK !
That was it !
It was black because nothing was connected on “Emissive Color” 
Thank you @ClockworkOcean !
Have a great day
