A method of providing adjustment data for a droplet deposition head , or for a data processing component for a droplet deposition head , the droplet deposition head comprising: a plurality of fluid chambers , each provided with a respective actuator element ; wherein the method comprises the steps of: receiving test data, which has been collected: by operating the droplet deposition head or a test droplet deposition head having substantially the same construction as said droplet deposition head , using each of a set of test waveforms, at each of a plurality of test frequencies distributed over a test range; and by recording the volume and velocity of the thus-ejected droplets, these recorded values, vol r and vel r , being represented within the test data; wherein the set of test waveforms includes a basic drive waveform and a number of adjusted drive waveforms (201-204), each of which corresponds to the basic drive waveform with the same waveform parameter adjusted by a respective amount, said waveform parameter being a continuous variable; for each of a plurality of adjustment frequencies distributed over at least a portion of said test range, determining a corresponding adjustment value, which corresponds to an amount of adjustment for said waveform parameter that, based on the test data, is expected to result in adjusted values for droplet volume and velocity of, respectively, vol a and vel a , which are substantially equal to targeted values for droplet volume and velocity, vol T and vel T ; and outputting a set of adjustment data representing a plurality of adjustment values, and a plurality of associated adjustment frequencies, including said determined adjustment values and their associated adjustment frequencies. receiving test data, which has been collected: by operating the droplet deposition head or a test droplet deposition head having substantially the same construction as said droplet deposition head , using each of a set of test waveforms, at each of a plurality of test frequencies distributed over a test range; and by recording the volume and velocity of the thus-ejected droplets, these recorded values, vol r and vel r , being represented within the test data; wherein the set of test waveforms includes a basic drive waveform and a number of adjusted drive waveforms (201-204), each of which corresponds to the basic drive waveform with the same waveform parameter adjusted by a respective amount, said waveform parameter being a continuous variable; by operating the droplet deposition head or a test droplet deposition head having substantially the same construction as said droplet deposition head , using each of a set of test waveforms, at each of a plurality of test frequencies distributed over a test range; and by recording the volume and velocity of the thus-ejected droplets, these recorded values, vol r and vel r , being represented within the test data; wherein the set of test waveforms includes a basic drive waveform and a number of adjusted drive waveforms (201-204), each of which corresponds to the basic drive waveform with the same waveform parameter adjusted by a respective amount, said waveform parameter being a continuous variable; for each of a plurality of adjustment frequencies distributed over at least a portion of said test range, determining a corresponding adjustment value, which corresponds to an amount of adjustment for said waveform parameter that, based on the test data, is expected to result in adjusted values for droplet volume and velocity of, respectively, vol a and vel a , which are substantially equal to targeted values for droplet volume and velocity, vol T and vel T ; and outputting a set of adjustment data representing a plurality of adjustment values, and a plurality of associated adjustment frequencies, including said determined adjustment values and their associated adjustment frequencies. <EOS>