Tom Friedman: Monsters and Stuff, Gagosian Gallery, London

There are a group of contemporary artists who are hunter-gatherers. They collect ordinary "stuff" and transform it into something magical. Tom Friedman is at the forefront of this school which also includes other Americans, Sarah Sze and the late Jason Rhoades, and British artist Tony Cragg. Friedman is the master of alchemy, not only collecting and arranging as Sze and Rhoades largely do but often using new materials. Unlike traditional alchemists Friedman is not turning base metal into gold but pencil shavings into expensive art works. Paper cups, dental floss, dust, pencil sharpenings, and hair of all varieties are here.

In the past, an artist was usually confined to traditional materials of paint or clay, bronze or marble. The Friedman equivalent is Ogre (2008) a piece in which the artist has evoked a monster out of bits of white paper, but this is not just a simple cutout or collage, here the paper has been pierced, twisted, torn and rolled into shapes that reassemble themselves into a discernible form in front of your eyes.

Early in the 20th century, vanguard Swiss artist Kurt Schwitters collected papers from the streets and turned them into fragile collages. Picasso incorporated toy cars and bicycle handlebars in his sculptures. Friedman takes these ideas and plays with them. Collages are made from shredded paper to create works that are beautiful but also contain playful trompe l'oeil elements – clutching fingers and hairy legs.

After recently observing an increasingly gloomy output by contemporary artists, it is a relief to see something that is colourful and humorous. Take Friedman's depiction of the Big Bang. It is a work on paper, the surface of which is covered in glitter. It is only on closer investigation that you notice the tufts of hair, the rips and peeling areas which reveal that the subject is not a happy one. Popping eyes remind you of the fake eyeballs that Friedman has made his own in the past. It is the closest that Friedman gets to saying to the viewer that one should not always believe what the eye is telling them.

To 25 July (020-7841 9960)