About Nine Degrees Below

Pine branch over Onondaga Lake at twilight
Twilight, my favorite part of the day, is when "sunlight scattering in the upper atmosphere" partially illuminates the earth's surface. Twilight ends in the evening and begins again in the morning when the Sun reaches 18 degrees below the horizon, at which point "scattered light from the Sun is less than that from starlight". My website's name, Nine Degrees Below, refers to the midpoint of morning and evening twilight, when the sun is nine degrees below the horizon.

Who am I and what's on this website?

My name is Elle Stone. I'm a digital photographer, Linux fanatic, and reforming pixel peeper. I'm also a writer, wife, and dog owner (or maybe she owns me, it's hard to say).

Nine Degrees Below is my personal website where I indulge my interest in photography and the open source digital darkroom. Here and there you'll find some of my own photographs. But mostly you'll find articles about color management and the open source digital darkroom.

Why use Linux and free/libre software?

With the release of Vista in 2007, Windows morphed into a DRM-laden entertainment center platform. I don't own any DRM content and my computer is for production, not entertainment, so I switched to Linux. Initially I was leary of using free/libre software for color management and image editing, but in point of fact even in 2007 free/libre raw rendering and color management software was better than the proprietary counterparts.

After getting my first digital SLR camera, the first thing I did was download and test every Windows raw processing program I could find. At that time I knew very little about open source software. To my amazement, the open source command line raw processor dcraw suited my needs far better than any of the proprietary raw processors that I tried. So I started testing and using more and more open source imaging programs, and eventually switched to Linux as my operating system. (As an aside, dcraw doesn't include the more recently developed open source interpolation algorithms. So today I use a range of open source raw processors, including my own floating point version of dcraw, which includes AMaZE, DCB, LMMSE, AFD, and VCD interpolation algorithms.)

After switching to Linux , I was very happy to discover how much better the open source Argyllcms is at calibrating and profiling my monitor (same colorimeter, same monitor), compared to the proprietary software I had used previously. As one example, the proprietary software I had previously used (and most shamefully on their part because this was purely a function of the software, not the actual hardware) did not provide a way to measure the monitor black or white point. Consequently and unbeknownst to me, even after calibration my monitor black point was set much too high. So all my "before Linux" images had completely crushed shadows on any monitor other than my own.

Back in 2007, free/libre image editing software still had a ways to go. Cinepaint was the only available software that offered high bit depth imaging with masks and layers, and Cinepaint had serious useability issues. Today Krita is a state-of-the-art high bit depth digital painting application. For photographers, high bit depth GIMP will be the final missing part of the free/libre digital darkroom.

Why a website devoted to color management and open source photography?

This website exists for three reasons: First, while perusing the internet for information on color management, I found a gap between the practical and theoretical aspects of color management. That gap is where all the creative things you can do with color management happen to reside. My articles on color management attempt to fill some of the void between theory and practice.

Second, the principles of color management and digital photography are the same regardless of which OS and which software you use. However, most articles on color management assume that the reader is using a proprietary OS (usually Windows) and proprietary software (usually PhotoShop). On this website the assumption is that you, the reader, are using Linux and open source software.

And third, Dave Coffin released the first version of dcraw in 1997. He's been updating it ever since as his wonderful and continuing contribution to the "intellectual gift-culture". Almost everything I know about digital photography, I learned from people who've shared their knowledge on the internet. This internet culture of shared knowledge is both humbling and inspiring. The articles on my website are my small effort to make a contribution in return.

As any teacher can tell you, a wonderful thing about sharing your knowledge is that the more you share, the more you learn, from insights you'd never have had if you hadn't tried to explain something to someone else, and also from having other people point out your errors (sometimes painful, but always welcome). If there is an article you'd like to talk about, send me an email! And if you see errors in something I've written (oh my gosh no!), a note dropped my way would be very appreciated.

Happy reading!
—Elle Stone, digital photographer, Linux fanatic, and reforming pixel-peeper