Abstract: There are disclosed coaters that repeatedly and intermittently apply a uniform, thin coating of liquid onto a support at a rate that does not exceed the maximum swell rate of the support. Thus, developer liquid can be applied to photographic paper supports without leaving behind liquid effluent.The coater features a delivery channel leading from a manifold chamber to a slit orifice, the channel being improved in that it contains a plurality of spaced-apart wall portions connecting the opposed flow surfaces of the delivery channel, that extend in a direction towards the slit orifice, and structure inside the orifice for coalescing the individual streams fed by these wall portions, into a continuous strip of liquid to be dispensed by the slit orifice.