Photo Editing

When it comes to post shoot processing of photos I have reservation in relation to the amount of post processing applied.

In my oppinion you have either photos that server as documentation for a point of view in point of time or you have images – an artistic work based on photos.

It is hard to draw a precise line between the 2 concepts, because some tools are not considered to disturb the documentation purity when applied a little or moderate, but when applied more intense it disturbes the validity of the documentation. E.g. if I take a photo in dark sorrounding (using high ISO, large aperture and slow exposure) I can get a photo that looks somewhat ligther that what was actual percived by those attending the scene. If I at home uses my post process to increase the ligth massively and get to an image that resembles daylight the validity of the documentation is disturbed.

Other tools is more obvious e.g cloning tool. I take a photo of a city landscape with beautifull buildings and ugly building cranes. At home I use the clone tool to remove the cranes. In my perspective we are no longer talking about a photo – with documentary validity – but about a work of art (an image).

I have chosen to use RAW, instead of JPEG, because the RAW file will provide 12 bit (my camera can deliver 14 bit) colorspace which gives a larger dynamic room for the picture. When exporting jo JPEG it will become 8 bit, but now I have a better oppertunity to control what part of the dynamic room that will be removed.

RAW files (*.NEF as I use Nikon) requires post processing in order to provide the finished product. Nikon did provide a tool, but it will only work on Mac-OS or Windows, not Unix, Linux or BSD. As all my computers run Linux I cannot use the Nikon tool, but must use what is available on the open source platform.

You are not left in the dark on a Linux desktop when i comes to RAW photo editing. Just to mention some: Darktable, UFRAW, Rawtherapee, DigiKam, LightZone, Shootwell are examples of available applications.

For my workflow I have choosen Darktable. Darktable is not alone a conversion and editing solution, it’s also an archive for the RAW photos.

Prio to chosing Darktable I performed some tests. My primary criterias was:
– ease of work
– speed of conversion
– quality of finished product

When I first tested Darktable I actually decided not to use it because it did not handle noise in a pleasant way, all the out put would have more noise that what I got from camera based JPEGs. But the situation has changed dramatically on later versions. Especially after the introduction of profile based noise reduction, where the application includes a profile for each camera and uses it for eliminating high ISO noise. When the right profile is applied, just activate and chose the right amount. Camera profile is selected automatically based on EXIF.

A nice feature in Darktable is that data is stored both in a SQLite database and in sidecar files. So if you crash the database you can recreate it by importing the photos and their sidecar files – rember to check the tick mark in settings.

When I arrive home from a photo shoot the first thing I’ll do is to get rid of the photos that is obviously not good and that I don’t think can be saved through editing. Then I apply post processing to the rest. Typically I will apply the following to a photo
– lense correction
– correct exposure
– noise reduction
– sharpness
– align horizon
– crop

For some photos I will work more on high- and low lights in order to dampen over exposed areas or to enhance under exposed area, while avoiding burn out in other areas.

What I do is mostly comparable with the works provided in the traditional dark room

For rare occasions I do not stop at this level. I have used the cloning and spot removal tool to wipe a disturbing building crane from the scene.

For creation of different sizes – for e.g. web publishing – I’ll go back the photo in Darktable. Do eventual new cropping and perform an export in the relevant resolution.

For years I used JPEGs as my primary format. When I need to edit these images I cannot use Darktable, but revert to other tools.

To perform a quick resize of pictures I’ll run them through ImageMagick – which is available on Linux, Windows and Mac-OS – with a script that applies the needed size, quality, naming etc. This is a very efficient way to handle a large number of pictures with little effort.

When the pictures arrives at the web platform (Coppermine or WordPress with NextGen Gallery) creation, rotation, annotation are handled by PHP GD Libary. The GD Libary can also be used locally with a local installation of PHP, by that you can build a function to fit almost whatever custom function your script needs.

When I just need to edit a single picture or if I should chose to manipulate an image further, I’ll go to the GIMP. The GIMP can be found to Linux, Windows and Mac-OS. It delivers approximately the same functions as e.g. Adobe Photoshop Elements and on top it has a build in scripting engine, that allows you to build workflows or automated functions.

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