I'm trying to make a normal map generator in Blender and I need to add Levels-like node. I'm using this tutorial about generating normal map from four pictures (https://dreamlight.com/how-to-create-normal-maps-from-photographs/#Photoshop - Create the Normal Map Layers header) and I'm stuck in a step where I must put Levels to 128-255 range on a Top-Right layer. Is there any way to reinvent Levels node in Blender Shading Nodes (Shading card)?
You can get the same functionality with the Color Ramp node.
Add > Converter > Color Ramp
And because the Color Ramp node uses 0-1 value range, just multiply your value by
1 / 255.
You can technically also do this with RGB curves, they're just a different tool for doing the same thing.