I added a "retro magazine paper advertisement look" to the image of a product design I made. I wanted to get a 90s newspaper effect. I generated simple wrapped paper look with background print is barely seen from the backside, I added an edge torn, and also I made an RGB to CMYK convertion to create "halftone" effect for magazine printing. Halftone ise a toning by using scale of dots according to the CMYK channel intensities. It can still be seen on newspaper printings I suppose (haven't checked for some years :) ).
More about this product design:
Technical details and sources I used for halftone creation can be found on the wikipedia.
And also I used the rgb to CMYK convertion algorithm from the second link from 101computing.net.
Hope you like it.