Some older hardcover books were printed in black ink on acid free paper - or paper with more longevity. These would be an excellent choice for collage work. Newspaper or magazine paper is designed for a short shelf life. Laser photocopies are better because the black ink is long lasting, carbon based. Inkjet prints are water-soluble and will fade. Coating with acrylic medium over the top of the newspaper, magazine or photocopy collaged elements will ensure a longer life. Plastic lasts for a long, long time. And if you want total assurance - try image transfer, where you remove all the paper. Or for more peace of mind - you can avoid the collage elements altogether and hand draw your image in a suitable medium.
Golden brand Polymer Varnish with UVLS (UltraViolet Light Stabilizers) is an acrylic varnish formulated to provide additional protection and help delay inevitable fading elements with impermanent and fugitive colors.