HDR Photo Development On Linux

Let me start this post by declaring if told something cannot be done I will find a way.  I have over fourteen years of computer experience with various platforms encompassing Mac, Windows, and Linux.  When I am told Linux is not suitable for photo development I completely disagree.  When it’s put to me that rendering HDR photos in Linux is impossible well now I’ve been challenged.  While each OS has it’s pros and cons I am confident in stating that Linux is not only a viable solution to developing your HDR Photo’s it is also a cost effective one.  If I were to rank OS’s for photo development, digital art and stability I would would have to say that Mac still holds the title, costly but is still what I feel is the best in terms of ease of use and stability.  Linux is my second choice having an undeniable stability when rendering large graphic files.  The only thing it lacks is applications that are easy to use.  Windows, in my opinion brings up third, mostly due to it’s lack of stability.  This being said the price for Linux is perfect, it’s free.  Donations to the Linux community and various application projects should be given but for those on a tight budget wanting to have professional results without the overhead can easily get started in Linux.

[singlepic id=176 w=320 h=240 float=left]In this tutorial I will walk the process of taking six Nikon Raw Format (.NEF) photos through the HDR and Tone Mapping Process.  The best of the original six photos is shown left at a web viewable size.  The average original file size for all six images is 9.5MB per image.  For those not fully understanding this is a decent print size for most images.  Smaller size files are used for web and computing use.  If you want to generate High Quality HDR use your camera’s raw format if it has one.  If not then I encourage you to shot in TIFF format if available.  If that is not available you may want to consider your first expenditure to be an investment into a digital camera that offers RAW and or TIFF Format.  The reason is simple.  These formats capture more information than a standard JPG.  Thus the ability to have a higher contrast, purer tones, and the best flexibility in the development of your photos exist in these formats.

The hardware I’m using for this process is an HP Pavilion dv3 at it’s original state, no extra memory or system modifications.  I have upgraded my previous Ubuntu 10.4 installation to Ubuntu 11.04.  There are only four applications that need to be installed to get started.  You can use the software center to install all four applications.  The applications needed are UFRaw, Hugin, Qtpfsgui, and Gimp ( usually included by default and you may not need to install ).  UFRaw is an optional package I recommend it if you plan to develop photos without going through the tone mapping process and just want a good developed shot.  Gimp is always recommended to fine tune your results.

[singlepic id=207 w=320 h=240 float=right]The first step, after installing all applications according to their instructions, is to open Qtpfsgui.  You should be presented with a blank window as shown right.  This window is very straight forward in and of itself.  The buttons across the top from left to right are New HDR, used to create a new HDR image file based on one or multiple image files, Open HDR, used to open a previously saved HDR file, Save HDR as, Save your current HDR as a single file, Tone Map, tone map the HDR File, and Exit.  We will be using each and every one of these buttons and I will provide a more detailed description where appropriate.

[singlepic id=177 w=320 h=240 float=right]The first step in this process either to tone map a single image or HDR and tone map multiple images is through the New HDR Creation Wizard.  Clicking this button will bring up the window to the right.  It is important to note that the only file formats accepted here are JPEG, TIFF, and RAW formats.  The camera information is utilized in the creation of the HDR.  It is recommended that RAW be used if available, then TIFFs, and as a last resort you can use JPEG.  One reason JPEG is less desirable than the other two formats is compression.  JPEG will compress the data and cause some data loss even if a JPEG is saved at 100% quality.  It is a fact of the image format.  RAW is the a variety of extensions, for Nikon it’s typically NEF.  These RAW formats are custom designed for the camera by it’s manufacturer.  Thus providing you with the best quality and file for your use from your camera.

[singlepic id=188 w=320 h=240 float=right]Click on the Load Images button as shown right to bring your photos into the program.  To make life easier I move all images I want to HDR into their own folder.  This makes it easier to select multiple files using the shift key.  For those of you not familiar with the shift trick, click on the top file in the list, hold down shift and click on the last file,  this will select all files in between.  Once you have all your files for the HDR Process selected click on the open button to bring them into Qtpfsgui.  It is important to note that when taking shots at multiple exposures for your HDR image it is best to use a tripod to avoid alignment problems.  The slightest movement and or wind could make alignment difficult if not impossible.

[singlepic id=201 w=320 h=240 float=right]Be patient after clicking open for each image has to be read in and the equivalent EV value for the HDR is scanned and determined.  I’ve yet to see it read a positive EV Value and I don’t believe these EV values will ever match what is on your camera.  I personally have never had a need to adjust the results although I have played with them a bit but find the wizard to do the best job of determining what these values are.  There is no progress bar for this step and that is a tad frustrating just be patient and wait I have never had this application crash.  It will come up eventually just wait.  Once it does come up aligning your multiple images is critical, even if you use a tripod is possible for the images to not stack up perfectly.  This is where Hugin comes in.  Check the box to align the images and make certain hugin… is selected as shown.  When your ready click next an prepare to wait again.  This time there is a progress bar.

Tomorrow I’ll be back to continue this process.  This should provided a basic what is needed for the first post.  The reason the post is being split up is more to keep page load time at a decent level.