# Digital Darkroom with Darktable
by Seth Kenlon

Last month, Jason Baker wrote a great article on [alternatives to
Picasa](https://opensource.com/life/16/3/top-open-source-alternatives-picasa). As
it happens in open source itself, the collaboration that followed his
article (in this case, in the form of comments by lots and lots of
opensource.com readers) generated a whole new list of great open
source photo tools. One that kept popping up was
[Darktable](http://www.darktable.org), which I use myself on a
semi-regular basis, so I thought I'd write up a quick intro to this
fine open source, cross-platform application.

Darktable is designed to be a photography *workflow* application,
meaning that if you want it to act as the centre of your photo studio,
it can be exactly that; you can techer your camera to it, bypass the
need for an SD card tool, shoot straight into Darktable, and then
review your photos, do filter-based non-destructive edits, and
publish. It's as complete a solution as you need.

I don't have the access to studio space the way I did at my previous
job, so my use for Darktable now is soley as a digital darkroom.

## Darktable Basics

If you don't have Darktable installed, you can either grab it for
Linux or OS X from
[github.com/darktable-org/darktable/releases](https://github.com/darktable-org/darktable/releases)
or, if you're on Linux (and why wouldn't you be?) then you can
probably find the latest version in your distribution's software
repository.

When you first launch Darktable, it may seem a little daunting. Its
interface is unique, but once you get the hang of it, it's actually
pretty simple. There are a few different modes that Darktable can run
in. Most are named aptly:

* Lighttable: an array of images, as if you were looking at your film negatives on a, well, lighttable
* Darkroom: the photo editing interface with non-destructive filters you can use to enhance a photo the same way you would in a darkroom (or, to be fair, at some later stage)
* Tethering: for studio use, permitting you to shoot straight to disk
* Map: a world map showing geo-location for the current image or images
* Slideshow: a presentation mode, much like a slideshow

Each of these modes is accessible from the labels in the upper right corner of the Darktable window, but you'll start in the Lighttable mode.

![dt_lighttable.jpg]

Initially, you'll not have any photographs loaded, so the first step
is to import images, either on a per-file basis or by directory. To
import, click one of the buttons in the **import** panel, located in
the upper left corner of the Darktable window.

You can import RAW images, or compressed images. When you import
images, a virtual "film roll" is created and each photo is tagged as
being a member of that roll. This is useful if you want to view only
the photos taken during one specific shoot, or over your family
holiday, and so on. Two things to keep in mind about this:

1. the film roll designation is only a tag. Photos are not moved from
where they live on disk when you import them into Darktable, so it's
safe to use tags to organise them within Darktable.  2. you can tag a
photo or group of photos with pertty much whatever you want. The film
roll convention is a logical, film-like analogy that Darktable uses,
but you can tag photos with any word or phrase that you find useful,
and then filter your view of photos by tags.

Once you have imported a few photos, you'll see them on a
lighttable-style layout. The lighttable itself can operate in two
ways: it can just be an array of photos (**File Manager** mode) or it
can be a dynamic photo viewer with mouse-wheel zooming and
middle-mouse click navigation (think Blender-style efficiency). To
switch between modes, use the **file manager** pop-up menu at the
bottom of the lighttable panel.

The lighttable is truly just a photo viewer; there's not much to it,
aside from looking at all of your many choices, and possibly rating
them (1 to 5 stars) based on how you (or your client) feels about
them.

Most of your work will be done in the darkroom panel, so select a photo and click the **darkroom** label in the ctop right corner of the Darktable window.


## Digital Darkroom

In the darkroom view, there are four main areas of interest:

1. The left and right panels hald filter and property palettes. These are what you'll use to apply effects to your photograph.
2. The center screen displays your image.
3. The bottom thumbnail bar provides quick access to your lighttable.

If you feel you need more room to work, you can hide panels and switch
to fullscreen, and if you find yourself doing any action repetitively,
you can even assign keyboard shortcuts for quick access.

Your workflow will probably start with the panel on the right. Any
filter placed on a photograph appears in the right filter
stack. Available filters are available in the bottom right panel,
labelled **More Modules**.

Try adding a filter, or enable one of the default filters by making a
change to some value. I usually start with the **Levels** filter to
enhance the shadows and highlights of my image. This filter is tagged as a member of the **Tone Group**, so you can find it quickly by clicking the **Tone Group** button at the top of the filter panel on the right.

![dt_group.jpg]

In the **levels** palette, adjust the black, gray, and white levels of
your photo. You should see the results immediately. Of course, these
are all non-destructive edits, so you can change your settings at any
time. You can toggle a filter an and off using the on/off icon on the
left of the filter title. This is the quickest and easiest way to see
a before-and-after version of what you are doing with any individual
effect.

All the effects you would reasonably expect to need as a professional
photography are available, and each can be added as filters to your
stack. If a filter is in the stack, activate or deactivate them with
the on/off icon.

Let's step through a few simple modifications on a sample photograph
just to demonstrate one way of working. I've already applied a level
filter, so next I'll use the **colour correction** filter. This filter
is tagged as a member of the **colour group**, so click on that button
in the top right quadrant of the Darktable window to reveal the
**colour correction** filter.

Changing the color balance causes the filter to become active. You can
shift the white balance as well as the overall saturation.

![dt_colour.jpg]

There are "special effect"-style filters, too, such as bloom,
vignetting, and grain. These are found in the right-most group: the
**effect group**.

Filters can have presets. Darktable ships with some presets already
defined, but you can add your own, too. To access presets, use the
menu icon to the left of a filter's name. For instance, if I decide
that I want my photo to be black-and-white, I can either click the
**menu** icon next to the **colorize** filter and choose **bw**, or
just right-click the **colorize** filter title and choose from the
presets that appear.

![dt_preset.jpg]

Any setting you create in a filter can be saved as a preset for later use by selecting **add new preset** from the preset menu.


## Version Flipping

Inevitably, you're going to reach a point in your work when you have a
version of the photograph that you like, but you want to keep playing
with filters to see if you can make it *even better*. The good news is
that you can have your cake and eat it, too. There are two ways to do
this; one temporary and one persistent.


### Snapshotting

Taking a snapshot of a work in progress is a great way to preserve one
particular set of filters while you continue to work. It does not make
a literal copy of the photo; it instead preserves the set of active
filters that you, at the moment of the snapshot, have applied to the
base photo.

Snapshots are meant to be temporary.

To take a snapshot of your work, click the **Take Snapshot** button in
the top left corner of the Darktable window.

Once you've taken a snapshot, it's listed in the **Snapshots**
panel. As you continue to work, you can always compare snapshots to
your photo's current state by clicking on a snapshot. This displays a
split-screen view of the snapshot and your photo.

![dt_snapshot.jpg]


### Duplicating

A more permanent solution to have one photograph serve as the base
image for several final versions is to duplicate a photo. Like a
snapshot, a "duplicate" photo in Darktable is not a literal copy of
the base image; Darktable just saves the filters you've applied to a
photo and shows you another representation of the base image with
those filters applied to it, as if though it had made a copy. This
results in you having two versions of the same "physical" computer
file in Darktable (but **not** on your hard drive).

To make a duplicate of a photo, go back to the **lighttable** view and
select the photo you want to duplicate. From the **selected images**
panel on the right, click the **duplicate** button.

![dt_duplicate.jpg]

You can now select one of the two images and continue editing in the
**Darkroom**.


## Exporting

Eventually, you or your client will decide which photos to publish,
and you'll want to export your work from Darktable. Exporting a single
image or a selection of images is done from the **Lighttable** view.

First, select the image or images you want to to export.

Reveal the **Export Selected** panel on the right and set the
destination of where you want to save the files. Select the format and
quality, and then click the **Export** button. In my examples, I'm
using relatively small JPEG files so exports are quick, but if you're
editing RAW, you might be able to sneak in a quick coffee break.

![dt_export.jpg]

## Customisations

Darktable has a very respectable, albeit somewhat hidden, preference
panel. To access it, go to the **Lighttable** view and click the
**Gear** icon hiding up in the right corner of the lighttable panel.

![dt_gear.jpg]

Most of the Darktable defaults are reasonable, but if you're
accustomed to keyboard conventions or averse to something Darktable
implements (such as using the **Backspace** key, generally used to
*delete*, an the *back* button in the lighttable view), you can change
almost everything about the keyboard layout.

![dt_prefs.jpg]


## Darktable

All in all, Darktable probably leans heavily toward the "pro photo"
end of the spectrum compared to something like, say,
[Shotwell](https://wiki.gnome.org/Apps/Shotwell) or Picasa, but if
you're looking to improve your photo workflow then it may be a great
move for you. If you are a prufessional photographer, then Darktable
is quite possibly everything you need from a digital darkroom app.

Try it out! Next month, we'll take a look at DigiKam, and then
LightZone.