Introducing curvr 2007/11/08
All inspirational credit, including the name, go to Aaron Straup Cope (filtr).
Curvr is a command-line tool that automates the most common operations I do in photoshop when I take pictures. I'm quite lazy and I hope that having this tool will make me take more pictures. This is the same line of reasoning that led me to an N73 and that is working out quite well.
I could just run Aaron's filtr script, which does a sort of Lomo-y thing, but that's not so much my style*. Instead, curvr perserves a little more reality and has a couple of key benefits. (* My style being slightly high-contrast but otherwise realistic.)
- Sets white- and black-points just like you can do in Photoshop's Levels dialog.
- Tweaks the color curve to make mid-tones just a touch darker and force more contrast.
The tweak of the color curve has a couple of nice side effects. Since it doesn't touch colors near the white- or black-points, things look pretty realistic. And for some reason, tweaking the mid-tones the way it does has the side effect of reducing haziness pretty effectively. Plus, skies pick up a really nice deep blue color.
My photography professor in college told us to use the red channel of the image to build black & white from color, rather than letting Photoshop convert it to greyscale. This advice carries through to the color mapping functions in curvr -- when replacing colors, the red channel is used as the key into the color map. It works surprisingly well.
Now the how-to-get-it bit. On a Mac you'll need MacPorts and a Terminal. On Linux you'll probably be able to pick a lot of this up from your package manager (update the Makefile accordingly).
$ sudo port install libpng jpeg
Now you can unpack and install GraphicsMagick. The GraphicsMagick source can be obtained at ftp://ftp.graphicsmagick.org/pub/GraphicsMagick/. I use version 1.1.10.
./configure && make && sudo make install
Finally, curvr is just a simple