ART is written by the Italian programmer Alberto Griggio, who aimed to keep the best of RawTherapee (RT) whilst making it easier to use. One of the new features is local masking.
I recently discovered ART when I wanted to apply 2 grad filters to an image. (RT) only allows one application of the effect. There is the obvious workaround of applying one grad filter, save the image, reopen the saved image in RT and apply a second grad filter.
I was hoping that ART would allow more than one application of a grad filter but it does not. However for my immediate requirement the masking feature of ART (Not present in RT) solves the problem.
Above is the image with just some basic global adjustments. What I now want to do is to apply a grad to darken the sky. But the sky is reflected in the water so that will require some darkening too, probably a reflection of the first grad filter.
Enter the Mask
The required mask divides the image into 3 horizontal bands: sky, ground, and water by creating a blurred or feathered rectangular mask across the middle, i.e. the ground.
We would then expect any adjustment to affect the area that is not masked, but the author of ART seems to use the word in the opposite sense – no problem, just click the “invert” button. Whatever adjustment is then applied will affect the sky and the water in a similar way to 2 grad filters.
Whilst this is a very specific case of requiring 2 grads I am sure it is not uncommon; whenever a sky is reflected in a lake any adjustment to the sky must be reflected in an adjustment to the surface of the lake. Below is the result.
Having been an occasional user of Hugin for many years, I have described my recent experience of stitching High-dydnamic-range (HDR) and normal, (Low-dynamic-range) panoramas from a set of 9 images shot one evening at Salford Quays. The article should prove interesting and useful to anyone new to Hugin, or to those, like me, who use Hugin infrequently and never quite become “experts”.
As usual, Hugin did an excellent job of stitching, but I recommend outputting an HDR file in EXR format for tone-mapping in, for example, Luminance HDR.
I have updated the page on this subject in order to clarify the distinction between calibration and profiling (or characterisation), and to remove reference to commercial operating systems now obsolete.
To avoid confusion I have now included only a version of each test card with sRGB profiles assigned and saved as jpegs. These should be viewed in an application that is colour aware (i.e. one that recognises and uses the embedded profile).
Basic adjustment of monitors and projection systems
When I last updated my page on this subject (2012) I decided that it was best to offer the test cards as .png files and leave it to the user to assign a profile (presumably sRGB) and to view the result in an application such as Photoshop. For convenience, I have now added a version of each test card with sRGB profiles assigned and saved as jpegs. These should be viewed in an application that is colour aware (i.e. one that recognises and uses the embedded profile).
Comparison of Demosaicing Methods available in Free, Open Source Raw Processors
My previous article included a table listing the various demosaicing algorithms offered by the four raw processors considered and I wondered why we (as users) needed such a wide choice. The table is reproduced below.I decided to investigate those offered by RawTherapee by looking closely at the detail in an image of tree branches against the sky – the same part of the same raw file processed by each of the algorithms.
Comparison of four free raw file processors: RawTherapee, Darktable, Lightzone and Photivo
With the exception of Darktable, which is not yet available for Windows, all of the applications are available for Windows, Mac and Linux. All are free and open source downloads.
I am looking for a raw file processor that will allow me to develop raw images to produce files ready for projection (at 1400 x 1050 pixels) and files at full resolution for further development, as necessary, to make high quality prints. I don’t expect to print directly from the raw processing application though this might be an advantage.
I have used both RawTherapee and Darktable for over a year and have recently tried Lightzone and Photivo so I will restrict my comments to these four.
The usual way of implementing a dual-boot system is by software. During the boot sequence the user selects the required operating system from a list. This is fine until one or other of the installed operating systems requires upgrading to a later version. Can we be confident that the dual boot will still work after the upgrade? At the very least we would be advised to backup everything.
There is an alternative which avoids all such worries; instead of switching between operating systems in software, use a hardware switch. Imagine a simple toggle switch on the front of your machine: UP for Ubuntu, DOWN for Windows – select the OS then power up.