maybe a better result by adding factor on this line :
li = lighti[2];

and also can play with these lines at begin og the phong section :

float spec = 32.0000;
float tran = 1.00000;

(same parameters than phong operators)

Very well. Many thanks, Master Code Guru. We are waiting for your return to wz4 development. Any estimations in that respect?

I'm ready :p

Very well, sir! As always, I'm at your service as to any sort of testing.

I comited fix on github, now phong specular color interact with color light
Are you ok with the fix ?

Looks good to me. The other thing is that it seems to place an unusual load upon my graphics card (nvidia gtx650Ti). I know that lighting is a chore for hardware, so that should be normal. Anyway, thanks a whole lot for the fix!

On the other hand, Blinn Phong shader remains the same. Will you change that also?

yes of course, I just forgot it, thanks.
done.

Works good! Many thanks!