Disclosed is a method of providing adjustment data for a droplet deposition head (such as a printhead), or a data processing component therefor. The method makes use of test data, which has been collected by operating the droplet deposition head (or a test droplet deposition head of substantially the same construction, e.g from the same batch), using a set of test waveforms, at a number of frequencies within a test range, and by recording the volume and velocity of the thus-ejected droplets, with these recorded values (volr, velr) being represented within the test data. Each of the set of test waveforms includes a basic drive waveform and a number of adjusted drive waveforms, each of which corresponds to the basic drive waveform, but with a particular waveform parameter adjusted by a corresponding amount. This waveform parameter is a continuous variable, such as pulse width or pulse amplitude. The method further includes, determining adjustment values corresponding to a number of adjustment frequencies, each adjustment value corresponding to an amount of adjustment for the waveform parameter that, based on the test data, is expected to result in adjusted values for droplet volume and velocity of, respectively, vola and vela, which are substantially equal to targeted values for droplet volume and velocity, volT and velT. The method outputs adjustment data representing such adjustment values and their associated adjustment frequencies, for example in the form of values for a look-up-table. Also disclosed is a droplet deposition apparatus that includes a droplet deposition head with data storage having stored thereon a set of adjustment data. The head uses the adjustment data to actuate its actuator elements with a drive waveform that is based on a basic drive waveform, but with a particular waveform parameter being adjusted by an adjustment value, which is represented by the set of adjustment data and which is determined based on it being associated with the current operating frequency of the actuator element in question. The waveform parameter is again a continuous variable. The adjustment data enable the head to eject droplets at frequencies within an operating range for the head whose values for droplet volume and velocity are substantially equal to targeted values for droplet volume and velocity, volT and velT.