Digital imaging basics - Digital darkroom

Developing in the digital lab

Some photos succeed so well that you won't need to post-process them. However, the untouched RAW data requires treatment anyway, since the built-in camera software, which normally handles white balance, sharpening, and other processes, is not used on them. With a little work, classical picture effects can be used on the computer, or completely new worlds. And as long as you're only working with copies and never with the original, you can try out any idea on a picture.

This kind of manual refinement isn't magic. Even without professional training, the digital darkroom lets you brighten shadows by hand, or neutralize colour depths. And beyond these corrections there is a wide range of options which allow you to simulate optical effects like gradient filters, or sepia tones and solarization. In the following sections, you will get to know a few techniques that enable you to have fun working with the most important tools.

Changing sizes

Even if you have determined the size of a photo in the camera menu, it can be changed quickly and easily. As there are so many different sized photo papers now available you can select a wide range of sizes to print at. You can attach a small version to an email or shrink it to monitor size to view it at a single glance. Nearly any image editing tool is capable of doing this.

If the photo becomes smaller, only a fraction of the original pixels can fit into the new dimensions. If the size is halved, for instance, the software must replace two pixels by combining their brightness and colour into a single pixel. However, the particular features of an image must be taken into account. instead of simply calculating an average value for the new pixel. For photos, the method called "bicubic" delivers the best results.

Increasing sharpness

"Unsharp mask" is the most popular filter to improve lines and details. Three controls adjust the effect to the motif.

Despite refined methods, you will sometimes have to sharpen some details sothat they come out right in smaller dimensions. The "Unsharp mask" filter is the best one to use, a classic in every programme. Three sliding bars allow you to focus on edges and outlines precisely, while surfaces are protected so that they don't look irregular or grainy.

The "Threshold" slider determines how high the tolerance should be before the sharpening is applied. If this is low, the sharpness filter will take action even for soft transitions, while a higher value limits it to already high contrasts.

The "Radius" determines how far from an edge the filter should have an effect. Too high a value here is normally the wrong decision, since you usually want to sharpen only narrowly along an outline.

The "Strength", finally, determines how intensive the correction should be.

Performing white balance at a later stage

With an analogue camera, it is difficult to adapt to lighting conditions. Colour filters combined with the right film are the only way to ensure that no undesired colour deviations occur in candlelight, sunlight, or under neon lighting. But even the default settings on the Epson R-D1s ensure the best possible balance. If the colouration should still turn a little bluish or reddish, then the problem is solved within seconds in a program.

With RAW data, all camera-internal processing, like white balance, is ignored. If you load this RAW data into the Epson RAW Plug-in for Photoshop, then all you have to do is move the "Temperature" slider to make the tone warmer or colder. If you can adjust a thermostat, you can get the hang of this.

Working with a grey card

Clever photographers work with a grey card. Thanks to this, the light meter has a baseline in any situation to determine the optimal exposure. If a corner of the grey card is seen in the photo, so much the better. In this you can set the "grey point" cursor and activate the pipette with a click of the mouse. Then you just click the tool on the grey card in order to swing the whole colour environment over to neutral values.

Elegant burning

It's simple to strengthen a vague image or to damp down harsh light to create a more romantic mood. You can simply move the "Contrast" slider in Epson Photo Raw to the left or right using your mouse. This gives you effects that could previously only be achieved by using photo papers of different hardness grades. The preview image shows immediately how the changes would look in the picture.

You can be even more refined using software like Adobe® Photoshop. This powerful tool works similarly to photo paper, with the digital gradation curve simulating the effects of light and the resulting bright/dark distribution in the photo. It can be bent like a rubber rope in order to darken an image, to lighten it, solarize it, or carefully increase contrast.

If you look at the tool more closely, you'll notice a black gradient as the origin of the curve which goes right into pure white - even if the curve is still a diagonal in the neutral state. If you use the mouse to mark the point in the middle, you can change the average brightness values. Stretch the curve upwards as shown, and then this range will be brightened preferentially. Bend the curve towards the bottom right to burn it.


The gradation curve is among the most flexible tools for image editing. Here, you see it brightening and darkening the middle brightness region.

And if you want to brighten lights and darken shadows, i.e. make the contrasts more intensive. This task is done using the S-curve shown. With a little experience, regions needing a little correction can be selected very precisely, and other curve forms can be developed. You probably already know the unusual lighting of pseudo-solarized pictures, which is extremely difficult to achieve. But a special curve form can be used to invert part of the tonal values into their inverses without having to use chemicals, paper, and so on. You simply set a point in the middle of the diagonal and pull the bright area into its inverse extreme, as shown in the monitor photo.

Contrasts can be intensified with an S-curve. The curve is good for effects too. On the right, it simulates a pseudo solarization by inverting the image parts above the median brightness. This has the effect that the photo combines both negative and positive.

After the hard work, you can enjoy the final outcome - beautifully retouched photographs with elegant black and white or sepia variants.

Stamp out little problems

The stamp tool helps make a photo radiate perfect beauty. If a photo of a tie has a little mark or the person in the photo had a small spot that appeared on the day of the portrait, it can be easily covered up. With a single click, you can pick up a small image segment, and then lay it over the embarrassing spot with another click.

Perfect skin can be moved to any point. One click selects it for the stamp, and another covers up.

For corrections in programs like Photoshop, you select the corresponding tool from the toolbar. Then, as shown, the mouse pointer will turn into a small stamp. In Photoshop, you also hold the Alt key down to pick up a small image segment. A click copies the area, then another click without the Alt key inserts it into any other location.

The stamp tool isn't just good for repairs. You can also use it to move noses and eyes in caricatures, or stamp a greeting card with flowers.

Fast colour changes

If clear contours and fine restraint are called for, you can easily convert the picture to black and white - for portraits or architecture shots. Using the right software, an image can be used to create an infinite number of variants in sepia, grey levels, or blue tones within seconds. A raw photo can be switched like a chameleon at the press of a button. After you have loaded it into the Epson Raw Plug-in, you can find the corresponding options in the "Film types" list. In the preview, you can immediately confirm whether you like the effect or not.

Light play with filters

If that's not enough, you can manipulate a black and white photo with an optical colour filter. For instance, the red filter can brighten faces or darken the sky in a landscape shot. A green filter, on the other hand, makes skin tone look better and brightens foliage. Even the intense colours of a slide film can be evoked using the "Glowing" selection.