Double checked: the texture is loaded, and the HDRI light (environment is on. No idea how to check tone mapping.

No idea how to check gamma setting on the texture.

I saw that while base color was set to the proper texture, all the other settings that include an image file were set to the white texture. I changed them all to blonde, but it still looks white in render. For all other colors (in this case using Fraser Hair), base color is the image for the hair color (black, red, brown, etc.) while the other settings like Glossy Layered Weight use the white texture. Those all look OK in render: black looks black, brown looks brown, red looks red. But blonde looks white.

I am adding the hair, then applying the iray material. No settings are changed from default. There are no lights except the environment map HDRI source.