kodak polymax rc II coming out grey

I have printed several photos on kodak polymax II RC paper and the whites (and boarders) are a light greyish colour. I do not know if you need certain developer or fixer for this paper, currently i am using ilford paper developer, ilford stop bath and ilford rapid fixer. The ilford paper i have used in the past have come out correctly.
So my question is, do i need specific chemicals from kodak? or could this problem be due to the paper being old ( i think this paper is somewhat old, was on special in the camera shop).
If anyone has any experience with this paper, any help would be appreciated.

thankyou.

More than likely it is fog caused by age. You may be able to reduce the effects, or even eliminate them entirely, by adding some benzotriazole to the developer. If not, you have some old paper for making lumen or carbon prints!

Where can i obtain this benzotriazole? Is it a common chemical i could buy at the camera shop?

thanks.

I've run out of polymax II, but it was the best paper for lumen prints ever. See my web site.

hi, what is a lumen print?

Also, what developer/fixer did you use for this paper? Thanks.