Abstract: An apparatus for metering required proportions of different fluid ingredients to make a required mixture (e.g. a colored paint) includes a rack of storage containers for the ingredients, each provided with a valve-controlled outlet and a receiving container mounted on a weighing device which is presentable to a chosen sequence of storage containers in turn to receive the required contribution from each. Metering of the necessary ingredient additions is effected automatically by a valve actuator carried by the support for the weighing device. Data processing control to optimize operation is described.