Using STL is one option, but I would recommend in stead that you create a reference mosaic dataset. I the reference Mosaic Dataset do to the functions then add any required colormap or color ramp. Prior to setting a color ramp you may want to include a stretch to bring say 32bit float value to a range 0-255. Also after applying a colormap it is advisable to add the colormap to RGB Function. The resulting service will provide an RGB rendered map back to the client. As with other service consider the most appropriate default compression to transmit the data back to the client. If using the ArcGIS web APIs then one can instead create a collection of such functions as part of the service and the client applications can select the required functions and define additional parameters as well. For performance also consider how best to transmit the imagery to the client application. If the resulting image is discrete then use LZW (or PNG) while if the data is continuous and does not have NoData areas then JPEG will provide much better compression.
