Photography DarkTable.........................

Forget mucking around with ropey Instagram filters, says Adam Oxford. Once you’ve started developing digital negatives you’ll never look back.

Forget ropey Instagram filters, says Adam Oxford. Once you’ve started developing digital negatives you’ll never look back.

Every couple of years or so a familiar headline pops up in RSS readers all over the world. “Film photography is back”, the gadget magazines shout, and cite the popularity of Lomo cameras or the fact that Kodak is manufacturing 35mm again as proof of the fact.

Unlike the resurgence of vinyl records, however, the film renaissance never quite lasts. Do you still use that Diana camera you bought in 2010? Or did you spot that Kodak was laying people off again over Christmas?

Film’s inherent drawbacks compared to digital probably means a full-scale resurgence is unlikely. And yet at the same time, there’s also something unsatisfying about pulling the same clinical-looking pics from your smartphone every shot, or applying the same Instagram filters as everyone else.

There is a way to insert a bit more craftsmanship into your photography, without having to take on the expense and inconvenience of film, that is shooting and editing in RAW.

RAW format photos are exactly what the name suggest. They’re the unedited data pulled straight from the sensor of your camera, so you see exactly what you shot and nothing else. When a JPG comes off of a camera, it’s been colour balanced, sharpened and had blemishes like chromatic aberration algorithmically enhanced. RAW photos require you to do all that yourself. It means you need to carry out a bit of work to the picture before you can print or share it. Think of it as the digital equivalent of developing a negative, but without any of the lethal chemicals.

Just like winding on film, however, shooting photos in RAW format also seems to have fallen out of favour in recent years. This is partly because most people never could be bothered with it, so fewer cameras even offer it as an option. It’s also because the high-end SLRs favoured by the folk who used to use RAW are really, really good at converting images to JPG formats these days – as good as most of us are at editing RAW files.

Why bother with RAW?

There are three answers to that question. The first is that there’s almost always more image quality you can discover in a RAW image, especially if you shoot challenging subjects. For example, wildlife photographers often have to capture subjects moving through different lighting conditions in the undergrowth. If you’ve got a slightly under- or over-exposed shot in JPG format, the chances are that a lot of wanted detail will be lost. It may still be there in the RAW image.

The second reason is that, just like developing film, turning RAW images into JPGs yourself doesn’t just feel a bit more authentic. You’ll also develop a personal style for things like the way you treat colours and shadows that will make your photography stand out.

It’s increasingly easy to get RAW images off of phone cameras with apps like Mark Harman’s OpenCamera for Android ( http://bit.ly/LXF235camera). Because of their limited on-board storage, phone camera software tends to compress JPGs quite heavily. A 23MB RAW image from a Samsung Galaxy S7, for example, is reduced down to a 2MB JPG by default. By comparison, a RAW shot from a Fujifilm X-T2 is 50MB in size, and a good-quality JPG is still 10MB.

All this means that if you don’t mind filling up your phone’s flash drive, there’s a ton of extra detail you can eke out of your phone shots with a RAW editor.

Cards on the Darktable

There are a few RAW editors available for Linux. Corel’s AfterShotPro3 ( www.aftershotpro.com) is a commercial option that can hold its own against Adobe’s industry standard Lightroom, and it only costs £54 for a full licence. In the open source world, there are two standout tools that you should take a closer look at: RawTherapee and Darktable.

Of the two, RawTherapee is easier to use, but we’ve generally found that it’s worth spending the time to learn

Darktable if you want the best results (especially if you use a Fujifilm camera with an X-Trans sensor, which produces different RAW images to most cameras).

One benefit of working with RAW images is that the editors themselves are non-destructive. They never change the original image, but rather create a linked XML file that lists the changes made. Only when you export the image into a new file format – such as a JPG – are the edits applied in a way that can’t be undone (but you can go back to the original RAW still).

The latest stable release of Darktable is 2.4.0, and it contains features that are well worth having. It’s not available in many distro repositories yet, though, so to add it to Ubuntu (for example) you’ll want to add the developer’s PPA. Install it with the following: sudo add-apt-repository ppa:pmjdebruijn/darktable-release sudo apt update sudo apt install darktable

Hear me RAW!

Just about every piece of RAW editing software has a similar look to the one that will greet you the first time you open up Darktable, with one large central workspace and two sidebars. On the left, you’ll find controls for managing files and finding pictures in your library, while on the right are the image-editing tools.

Darktable, however, does look slightly more intimidating than most. It’s not just because it’s has more built-in tools than most – nearing 50 at the last count – it also plays Linux old-school. Just about everything you see in front of you is capable of being customised and configured. Each collapsible box in the sidebars has a title and a small row of icons in its header, which Darktable calls the Expander bar. Only one Expander can be open at a time by default, but you can have several tools open by shift-clicking the arrowhead.

Where most RAW editors will enable you to store a set of default settings to apply to an image on import, Darktable goes even further and makes it possible to store per-tool presets using the little burger menu on each tool box. You can even clone tools, to apply two sets of edits using the same tool if you want. You might do this if you’ve built up a set of those presets for colours, for example, and want to apply two or three but still have the option to tweak each effect.

In other words, Darktable can be customised to fit your own particular way of working, but that freedom comes at the expense of a lot of clutter and hard-to-hit icons on the screen that you’ll probably never use anyway. Don’t worry – after a few minutes you won’t notice the things you don’t use, and it is software that’s worth persisting with. It just might strike you as odd that there’s so much flexibility, but not an easy way to change the theme without hacking config files.

More importantly, Darktable is – again like other RAW editors – a combination of two applications. One is a workflow and file manager for quickly viewing, renaming and tagging images, and sorting them into the ones you want to edit and the ones you don’t. The other is the editor itself – Darktable borrows from classic photography speak, splitting these applications into the Lighttable and Darkroom. You can switch between the two with the tabs at the top right – there are other top-level features under Other, but they are more a novelty, such as a map of geotagged photos in your archive than hugely productive.

The first step, however, is getting images into the software. You can use Darktable to import directly from a camera, but you’ll also want to import your existing image library in there. It’s likely you have a Pictures folder somewhere, subdivided into other folders by date and theme, which contains RAW images. In the top right-hand corner of the Lighttable view, there’s an Import box. Click Folder, and point that at the top level of your picture archive and Darktable will import all your images into its database recursively, along with their location and metadata.

Once you’ve done that – and it can take a long time if you have a lot of images – getting pictures onto the Lighttable view bears a bit of explanation. The Collect image box controls what appears in the thumbnail grid. The first pulldown menu gives you options to view images with a particular tag, shot on a certain date or sorted into a folder or “filmroll”. Clicking folders gives you a classic file tree for navigating to a picture, and clicking a Filmroll gives you a list of the lowest level folders in that tree.

Neither is quite perfect: Filmroll can be a little unmanageable if you have hundreds of folders of photos acquired over the years, but using the Folder explorer shows not just images in the folder that you clicked, but all images in recursive folders, too. This functionality is handy if you can’t remember exactly where you stored a picture, but a little overwhelming sometimes.

One challenge with the navigator is getting back to the main list once you’ve selected a folder. You have to click the pulldown menu on the right and select “Clear this rule” (or add a second rule if you want to add photos to the view). It’s a bit clunky, but you get used to it.

Once you’ve picked a Folder or Filmroll, you can tag images with stars or colours by hovering over them and clicking icons or using keyboard shortcuts on the number pad (1 is equal to one star, 2 is two stars and so on). This is a quick way to filter out the non-keepers and focus on the images that need extra editing. The View menu at the top hides unmarked images.

The left-hand sidebar contains tools for adding tags, geotags and editing metadata. You can apply these edits to single images or select multiple thumbnails using the Shift and Ctrl keys. It’s worth pointing out that you can zoom or shrink the thumbnails using Ctrl and the mouse wheel.

Entering the Darkroom

Once you’ve got the images you want to work with, you can either select on and click Darkroom or just double-click an image. The sidebars will both change and the grid is replaced with the image you’ve selected. Thumbnails from the selected grid appear at the bottom of the screen in a filmstrip – you can quickly navigate to the next or previous images using the Backspace and Space keys.

Most of the tools on the left are self-explanatory, but the History and Snapshot tools are worth digging into. As mentioned above, RAW editing is non-destructive. What you’re creating is a script of effects applied in a sequence to the RAW photo. So you can rollback edits using the History pane that records all the steps you’ve taken so far. The Snapshots box can be even more useful: use it to save a set of edits so you can switch between different versions of an image and compare which is the better.

On the left, you’ll find the editing tools themselves, which are grouped together by function. The Basic tab contains simple exposure correction, crop and rotate and the white balance tools, as well as the very non-basic Demosiac control. This is the algorithm used for the first stage of processing, combining the red, green and blue pixel output from the camera sensors into a single image.

Other controls are grouped by Tone and Colour, Corrections – which covers sharpening tools and noise reduction – and Effects. The Effects group contains tools that are useful for general processing, but also for artistic purposes, such as vignetting.

Once you’ve changed the settings or clicked on the power button within a tool it becomes “Active”. You can turn it off (see what it looked like before the settings were applied) using the power icon next to the name.

All in all, there are over 40 tools and filters at your disposal, but you’ll probably only use a handful regularly – and Darktable has an option to favourite those in a separate tab that you’ll probably and here’s where Darktable can become a little overwhelming.

As well as standard options for selecting the white or black point of an image, or correcting exposure with a slider, there are more unusual options like the Zone System control. This tool treats the image by dividing it up into zones of lightness from black to white, using a system devised by

iconic US landscape photographer Ansel Adams ( www.

anseladams.com). By clicking and dragging the gradient bar, you can change the lightness values of each tone individually.

The Zone system is a great tool that’s easy to get used to and produces great results, but like most tools in a RAW editor, the same results can be achieved with something else (Levels, or the Tone Curve). Most of us settle on the four or five ways of editing and filters we’re most comfortable with, and rarely touch anything else. Darktable takes this into account with the Favourites tab ( see below left).

Define sharpness

One of those tools will definitely be the Sharpening control. RAW images always tend to be softer than JPGs because that’s how images come off of the camera’s sensor. There are no hard outlines in nature, and in-camera processing to produce a JPG involves applying some manufacturer-defined level of sharpening. With a RAW editor, you get to decide how sharp you want an image to be using three sliders: one for the number of adjacent pixels taken into account when applying the effect (radius); one for the strength of the effect (amount); and one that determines the level of softness at which the effect is applied. Moving all sliders to the right will create a harder, sharper image – just don’t oversharpen or every object will be surrounded by a glowing halo.

The other key control to master is exposure compensation, which remains the main reason to use RAW over in-camera processing on high-end cameras. If you’ve never tried it before, then you’ll be surprised how much detail you can find in dark areas by increasing the EV value, a fraction of a stop. The same is true for blown-out highlights and reducing the EV amount.

Other than that, there’s plenty of technical literature you can read about how common tools such as the Denoise filter, levels, tone curves and so on, but the best way to learn is to simply grab a photo, dive in and try stuff out and have fun.