AC25 surfaces preview bug?

[Paul King]

For some reason when I create a new surface, even if I duplicate the 'Exposure to light' parameters exactly of another surface, the resulting preview is always either glaring white, or pitch black

Below is a standard built in Archicad colour - preview is fine.

This is a colour I made by duplicating another colour (also with an ok preview)

Why is this?

How do I fix already defined new surfaces exhibiting this issue? 

(I tried the workaround of duplicating and re-defining another colour not exhibiting the issue - but  the result in the duplicate is always glaring white or pitch black preview - and same appears in the surface painter pallet, and neither bear any resemblance to the colour as displayed in 3D view )

Is this a known bug?

[Barry Kelly]

I don't know why it appears so different, but your shininess is 75 instead of 50 and the specular colour is slightly different.

Barry.

[Paul King]

Thanks Barry - sorry you are right (pasted the wrong version) - but even tweaking these makes no difference.

[Paul King]

Thought I had a workaround, but turns out not to work.  Sadly the forum software wont let me simply delete this post.