What causes this?

[kingjin]

All settings are the same, just change the third object color (left is 255white, the right is the 212 gray), rendering in the standard engine, why the background color is not the same? Why the first objects and second not the same light? Why the third object is not 212 gray, while still white? What have I done wrong, anyone's advice welcome, thank you!

[Roy Hirshkowitz]

What type of background is it?  For example, is it nXt's sky?

[kingjin]

Yes, it is nXt's sky.

[Roy Hirshkowitz]

All of the colors, including the nXt sky, are subject to exposure control (tone mapping).  Changing any one of these components in a simple scene such as yours, can alter all of them, since it can drastically change the metering of the entire scene.  You can use alpha channel compositing to control the background colors, if you want to.  For the object colors, you can lock the tone operator when you like it-- OR-- you can adjust the Brightness manually.

[kingjin]

Thank you, I would like to ask how the lock the tone operator?

[Roy Hirshkowitz]

After rendering (at least one partial rendering is required) the Lisp command:

(nxtlocktoneop 1) will lock the current exposure settings and prevent scene metering.

(nxtlocktoneop 0) will release the lock

This command is not persistent-- it only lasts for the current session.

[kingjin]

Roy Hirshkowitz, thank you very much, I know the reason. About automatic exposure or with the default settings of the software, according to thecharacteristics of back to adjust the corresponding settings. Thanks again.

[kingjin]

The type of background colors and images is also is such.