There is a Humbrol Conversion Chart (P1158) available from the site shop that lists all the Humbrol range and conversions for Vallejo Model Color (with this you can use a Vallejo chart for Model Air). P1158 also converts to Gunze Sangyo Aqueous Color, Mr Hobby, Lifecolor, Modelmaster, Revell, Tamiya and Xtracolor as well as BS FS RAL & RLM colours.