Thanks, Keith. Coincidentally, the latest issue of Digital Photo magazine (issue 202, January 2016) features a number of articles about HDR and from a quick glance appears to cover the topic comprehensively. There is also a free download of a "special" plugin edition of the Photomatix software iwhich will work with Photoshop and Photoshop Elements. It is described as being an "Essentials" version, so I would expect it to be lacking some of the more advanced features which are only available by purchasing the full programme.
http://issuu.com/photoanswers/docs/dp_jan16_samplerI would also add that the HDR function in the latest version of Lightroom (6/CC) will work with just two captures, one under exposed and the other over exposed. According to Adobe there is no need for a third capture at the metered exposure. It produces a new image in DNG format with natural tones which can be processed just like any other Raw file.
https://helpx.adobe.com/lightroom/how-t ... w--2015-04