In Part I
, I wrote about the capture of images for processing into HDR pictures.
I need to add something I left out, namely that the capture should be in RAW format and not JPEG.
And the reason is that HDR processing creates lots of artefacts. To minimise this we start with minimising artefacts in the first place at capture. JPEGs create additional artefacts of its own, thus aggravating the "problem" after HDR processing.
Of course it may not be any "problem" at all to your eye and your aesthetics, but it will certainly be if you intend to submit the HDR image for sale as stock photography.
So all the processing discussed here is aimed to attain a processed image quality that can meet the highest technical standards for stock photography.
I realised also that I need more than one blog entry to discuss fully the processing to attain these quality standards.
It is perhaps justifable too, for HDR images are all about processing. The camera capture was, merely, to aquire images that are optimal for HDR generation.
In this blog entry I will discuss processing generally as an introduction.
Firstly I will only discuss the use of Photomatix as the primary HDR generator. You can create HDR images with Photoshop, and even manually by hand, but I will not discussed that.
Photoshop's auto algorithm for HDR creation is also available in Photomatix, specifically called "Exposure Blending". This will not be discussed too.
Secondly there will also be two, or three, parts in the processing, namely the HDR generation, and then the post HDR processing.
In the former, I will discussed my experience of using Photmatix tone mapping algorithms, and also in two parts, ie Part IIA and IIB.
In Part IIC, in the post HDR generation processing, other third party software, like Lightroom, Photoshop and Noise Ninja will be used, and it is particularly focused on eliminating artefacts and noise. For apart from artefacts, high noise levels and severe chromatic aberrations are also other non acceptable characteristics of out-of-the-processor HDR images.
Lastly, in this introduction, I must add that there are plenty of room for experimentation, in the use of Photomatix or other software and workflow. You can ascertain this by googling HDR, or HDRI, in sites such as flickr or elsewhere.
What I will be discussing are only my experiences, and I am sure I have not seen it all yet.