# Categories

Study 0 min.

## Who are the darktable users in 2020 ?

Study 22 min.
The core basics of design are to know for whom you design, that is who are the users of your solution, what they expect and what they need. It is also necessary to assess if the actual user of your product is the one you designed it for in the first place, that is, who is missing from your user base, to avoid the survivor bias . This is unfortunately overlooked in FLOSS and it is often not well regarded to collect user data.

## Interpolating (hue) angles

Study 9 min.
In image processing, retouchers may want to apply a saturation boost on specific hues only. Typically, uniform saturation corrections follow a basic linear transfer function $sat_{out} = gain \cdot sat_{in}$, where $gain$ is a real positive constant. To target specific hues, we simply rewrite $sat_{out}(hue) = gain(hue) \cdot sat_{in}$ where $gain$ is then a function. The most common way to declare $gain$ is to provide users with 8 discrete saturation nodes for 8 evenly-spaced hues, and interpolate smoothly between nodes.

## Websites suck.

Opinion 6 min.
I have spent the past month working on an AI-based search engine. When you go on darktable sub-Reddit, you will find the question “why do lighttable’s thumbnails look different from darkroom preview” asked every next week. The question is answered many times on this sub-Reddit, on various forums, and I even put the answer on the main Readme file, displayed on the Github main page of the software. To no avail.

## You need to reinvent the wheel all the time

Opinion 7 min.
There is this mantra that I have been hearing too much in my life : “don’t reinvent the wheel”. People mean that as a metaphor trying to discourage you from redoing something that is already done, and by that they actually want you to use whatever software application or library instead of coding your own, as if it was automatically a time and resource saver. It’s not. First of all, despite its apparent common sense, this statement is incredibly ignorant : the wheel has been reinvented many times, typically for the sake of performance.

## Design by committee will not save FLOSS

Opinion 6 min.
The opensource ecosystem is keen on its mantras. One of them is that being an opensource dev/maintainer is a thankless unpaid job. And while that may sound like a selfless act of benevolence, there is another way of reading it : a selfish way of avoiding professional responsibility, while still exerting some amount of power and decision. Which is the egg and which is the chicken then ? It may not matter, but the quasi-hagiographic founding myths of opensource need to stop.

## Open source and professional photography : lies and wishes

Opinion 8 min.
There is one thing you will find on the home page of pretty much any open source (call it libre or free if you will, those lines are blurred) image editing software : the promise that it is, somehow, suitable for professionals. Marketing has abused that word for decades, it is only natural that it should affect non-commercial and non-profit projects as well, just to try to buy some cheap credibility.

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