One of the most exciting things I think modern photography has is the ability to make special effects thanks to the computer. I have always been fascinated by mixing colour with blank & white elements. So, after giving a fast reading to the Darktable 3.2 manual, I found a way to create the effect I want: blank and white but one colour.
Who doesn't remember that dark scene of the Schindler's List film where a girl in a red jacket is walking. Then a few minutes later, you identify her corpse from a pile of bodies. Well, I will show how to make this happen, but with a more joyful image.
The picture above was taken by me with my Canon 90D in the last Christmas Parade 2020 in my local city. The left picture is the original JPEG from the camera, the middle one is the product of the RAW processed with Darktable and the right one is the same photo with the additional effect of a monochrome photo while keeping red-orange colours. There it is what I did.
(So, this could be a very good week or very bad. My old desktop started to behave very annoyingly, freezing every ten minutes is not the ideal scenario. Happily, I had a spare CPU I was using for Windows applications only, so I decided to take it. Because I have some spare AMD Radeon R9 290 GPUs, I decide to install one of them.
Again, I have been getting into photography so again, processing RAW files with the CPU is not a good idea. Not even if your desktop has twelve cores. So I had had to figure out a way to make it work.
As I had described in the article where I made my discrete NVIDIA work with Darktable, this software needs the IMAGE support. So, the situation is the following:
Here it is what I did to make it work.
As I have written before, after more than five years it was time to retire from hard work my trust old laptop. I decided to get an HP Omen. I must say the hardware is quite amazing and to get the best of it I installed Mageia 7 (current version when writing the articles).
Recently I have been getting into photography (I will write about that later) and of course, getting the software to develop RAW files is a must. I think Darktable is the best for it; however, this kind of software is really heavy, even this super powerful laptop with 12 cores at 3+ GHz got dizzy. Fortunately for us, Darktable supports GPU processing which offloads the CPU and displays the images almost right away.
Configuration to make this possible is kind of tricky. I will put here my notes hoping it will help other fellows Linux photographers. My notes are on Mageia but I am confident that anyone could apply them to their own Linux distribution.
It took me weeks to figure it out.