ZYKLON-B, a suite of screenprints produced in 2011, was inspired by Carvalho's recent visit to the Jewish Museum in Berlin, and it addresses the events of the Holocaust in a sequence of prints based on amateur photographs he saw in the Museum. Re-scaled and printed many times their original size, the images are blurred, ambiguous, ominous and hard to read. Showing various acts of violence against Jews and buildings such as the SS HQ in Berlin, the images make up a disjointed but telling narrative. The portfolio is subtitled 'Let the sun see you crying' (adapted from the title of the song by British 60s band Gerry and the Pacemakers, 'Don't Let the Sun Catch You Crying') and the prints are printed in black on bright yellow. The choice of yellow is itself ambiguous - yellow with its associations of sunshine can be positive and cheerful, but it is also symbolises disease and decay and is used as a warning sign for hazardous substances. The cover of the portfolio has been carefully considered: made of grey cardboard, with black binding and black stencilled lettering, it carries associations of packing cases, freight, concrete bunkers. It is held closed by a band of thin black elastic which is knotted in such a way as to suggest barbed wire.