This is just a simple model, and in addition, the effect of this image is what I wanted; it was created using the Arnold renderer.

Hi, Kirgman
I want to use a few images to illustrate my problem:
1. The model has two different angles;
2. The white part of the "curvature map" cannot be adjusted to pure white;
3. If "invert" is checked, the black part almost disappears;
4, 5, 6. Using the nodes "correction," "gradient," and "remap," I cannot adjust the values of the white part to 1.
In summary, I want to achieve perfect "black" and "white." Is there any way to do this?

The curvature map cannot adjust the contrast, whether using gradient nodes or color correction nodes. Moreover, the curvature map shows a significant difference from the original image after inverting.