Workshop – processing and fixing a backlit picture – HDR with LuminanceHDR

99% of my pictures are processed with RawTherapee, LuminanceHDR or fusions of both with Enfuse. I rarely use Gimp or any other developping software.

Because of that, when I decide to work on a picture in HDR, I send it straight from RawTherapee to LuminanceHDR with the external editor icon ( left – below ) or Ctrl+e.

LuminanceHDR is set as external editor thru : RawTherapee -> preferences -> General -> external editor -> other command line -> /usr/bin/luminance-hdr  ( this is done in Xubuntu Linux, in Windows use path to program folder and exe )

The picture is send to LuminanceHDR, and opened in the preview window on the right side. When looking for the best method and settings, the first thing to do is to set the preview result size to 1024 x 683, i think this gives the best balance between program speed and a good idea of how the picture is going to look like when done.

Altough the choosen subject is a backlit picture, the below explained way of processing, setting parameters and values are also valid for any other picture you want to convert to HDR

Also notice that I work with 1 picture, in stead of a set of bracketed pictures. shooting a bracketed set of a flying airplane is I think impossible. For creating an HDR it is also not mandatory to have a bracketed set, but if you don’t have one and would like to create an HDR this way, you can always create a set using different exposure settings in RawTherapee.

In the next step I have choosen Mantiuk06 as operator and the standard settings for tone mapping and processing – then I hit the update preview button to see the result – notice the artifacts around the wings of the airplane, clouds are definitively present now, but the picture actualy looks awefull, not ?

same settings but added contrast equalization :

next are settings I often use to start with, it depends on the picture/subject to use other values – best is to try out things.

  • operator = mantiuk06, in my eyes the best possible HDR operator compared to the other ones, the below parameters and values are only usable with this operator.
  • contrast factor = I noticed that when using higher values, artifacts getting fewer – best is to start higher than 0.50 – I mostly use 0.80 – 0.90
  • saturation factor = getting more color in the picture – best is to go higher than 1 – I often use 1.5
  • detail factor = in an HDR you want detail !, default is 1, a lot of photographers advice not to go over 5 – but I found out that by using higher contrast factors, it is possible to use higher detail factors, I use sometimes up to factor 30 ! – best starting point is factor 10
  • contrast equalization = depends on picture, try one with and one without, then compare
  • result size in set to 1024 x 683 for preview only ( faster ), final result is processed at maximum resolution, you will see that the output is even better than the preview.
  • pre-gamma = default is 1, I find settings between 0.5-0.8 better looking HDR, I often use 0.7

to be continued …

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