Coloring Monochrome Images Digitally

By Tony Worobiec Back to

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One of the possible drawbacks of abandoning the darkroom is the danger that some of the more quirky techniques risk being lost, and the hand-coloring of black-and-white photographs is a good case in point. Before the advent of color film, if a photographer wanted to present his work in color, he was required to apply subtle dyes to a silver gelatin print. This technique has enjoyed a revival in recent years, but it is a time-consuming exercise requiring a fair measure of skill. In order to recreate the delicate colors one associates with this technique, the pigments need to be applied using thin washes; to achieve this digitally, an equal degree of restraint is required.

There are two ways of recreating this “hand-coloring” effect, firstly, by incrementally desaturating an image, or secondly, by desaturating the image completely and then reconstructing the hues using various Photoshop techniques. With either method, it is important that the color remains subdued.

In common with most imitative techniques, it helps to understand how they are achieved in the darkroom before trying to create them digitally. Unquestionably, the most popular method for hand coloring involves using Marshall’s Oils. Similar to traditional oil- paints, these translucent pigments are designed specifically for this purpose, and are applied directly onto the print using wads of cotton wool. The intensity of the color is determined by how thickly these pigments are used, but the emphasis is to keep the outcome subtle. The results are extremely appealing, harnessing the advantages of both color and monochrome. It is also possible to be selective about which areas are colored.

Working from a Raw File

To begin one method of “hand-coloring” a digital photograph, call up a Raw image, and leave it in full color (Figure 1a). This becomes the background layer. Make two duplicate layers, which become Layer 1 and Layer 2. Activate Layer 1, and desaturate it using the Channel Mixer (Image > Adjustments > Channel Mixer), making sure that the Monochrome box is ticked. Then rename this layer “black-and-white” (Figure 1b). It is a matter of choice, but I do prefer to increase the contrast of this layer at this stage. Activate Layer 2, which is retained in color, apply a Gaussian Blur filter using a radius of 18 pixels, and then rename it “blur.” Finally, blend the two layers using the Opacity slider or by applying Overlay from the Blending mode. One of the great advantages of hand-tinting is that you can apply or remove colors at will. A simple method for adding further colors is to make an Adjustment layer and apply a Photo filter (Figure 1c). This gives the impression that the black-and-white image has been subtly toned prior to hand coloring. Go to Color in the dialog box, select, and then use the Density slider to determine the strength of the added hue. I do not normally use Photo Filter, as it applies a universal color over the entire image, but if used subtly, it can increase the sense of oils being applied over a black-and-white print.

Emulating perception

The eye is capable of being far more selective than the camera. When photographing the image in Figure 3, I was drawn to the red illumination, largely unaware of all the other surrounding colors. To recreate what had initially caught my attention, it was necessary to remove all color with the exception of the reds. The major task was to make an accurate selection, which is the key to most digital hand-coloring.

First, I made a Background copy, then using the Magic Wand tool set to a Tolerance of 50, I picked out all the larger areas of red. Remember, to add to a selection, hold down Shift, and then click on the areas you still wish to include in the selection (see Figure 1). Alternatively set the Magic Wand tool to Add. As some of the areas to be selected are diffused (particularly the area surrounding the neon lighting), it is necessary to feather the selection, in this example by 40. Once all the red areas have been successfully selected, I inversed the selection (Select > Inverse), and the background desaturated. Saving the selection at this stage helps, as further local adjustments can still be made later on.

Isolating the red from the rest of the image, introduces a strong graphical element (Figure 4). Other smaller areas of red are dispersed throughout the original image (particularly inside the window), but including these would have compromised the simplicity of the design. Adding just a hint of sepia helped to introduce a slightly warmer feel to the background. If the red appears too bright, it can easily be re- selected and slightly desaturated.

 

Reconstructing a black-and-white image

While to some this might appear a laborious task, there is great value in being able to desaturate an image and then reconstruct the colors precisely as you would wish to see them. There are of course various Photoshop facilities for changing colors within an image, but the results lack the hand-crafted quality that distinguishes a hand-tinted image from a color photograph. If you wish to recreate the subtle hues that characterize early 20th century postcards, it is best to start with a monochrome image (Figure 5).

It is surprising how easily a monochrome image can be transformed with just the smallest suggestion of color. In the image in Figure 5, I decided to only work on the flag. I first selected the flag’s blue field using the Polygonal Lasso, and deselected the stars using the Magic Wand tool set to Subtract from Selection. I then made an adjustment layer and dialed in a mixture of blue and cyan using the Color Balance menu. I then selected the stripes (once again using the Polygonal Lasso tool), created another adjustment layer, selected Color Balance, and applied a mixture of red and yellow. Finally I selected the entire flag and then inversed it; with the Highlights selected, I added a small amount of red and yellow in the Color Balance menu to give the impression of a sepia background.

Full palette

Having applied color to just a small area, try using a full palette of colors throughout an entire image in the manner of those early hand-tinted postcards. Once again it is important to start with a desaturated image in RGB mode. It helps by giving the entire image a gentle tint, using either blue or sepia depending on the mood you wish to suggest.

Good selections are the key to successful hand-tinting, so be prepared to use the full gamut of selection tools. Get into the habit of saving selections, as it may be necessary to make changes further down the line. In order to recreate that sense that the color has been applied by hand, feather all selections, but by not more than by 5 pixels. It also helps to make duplicate layers at each stage so that mistakes can be easily deleted.

The Airbrush tool most closely mimics how color was applied on traditional hand-colored images. Set a large brush size, (if I am doing a sky area, it is not uncommon to set it at 500 pixels or more), then set the blending mode to Overlay. Choose the required color from the Color Picker palette. The Opacity and Flow settings determine how quickly it is applied, but if you are not too experienced using this tool, reduce both, as it is far better to apply “washes,” and build up the colors gradually. When using the Airbrush set on Overlay, the highlights and shadow detail are unaffected by the applied color, something which is virtually impossible to achieve in the darkroom.

Once the sky has been accurately selected, large sweeping brush-strokes can be applied without affecting the diner.

Having inverted the selection, I applied adjustment layers and shifted colors using the Color Balance dialog (Figure 7c). The building was split-toned using copper and blue. The neon lighting also was selected and colored individually using Hue/Saturation. While the applied colors of the final image (Figure 8 ) could never reasonably be considered “realistic,” they nevertheless capture the character of the hand- colored postcards that were so popular in the middle of the last century.

Hand-coloring step-by-step

Because of the simple clear-cut lines, the image of the old car in Figure 9 screams out to be hand-colored. Starting with a desaturated image is almost like starting with a blank canvas. It is possible to introduce as much color as you wish, and once again, selection is the key. Always start with the larger areas, and then proceed onto the smaller ones. In this example, there is a natural division between the sky and the other areas; I therefore selected the sky using the Polygon Lasso tool feathered by 2 pixels. I saved the selection, made an adjustment layer, and then colored the sky using the Hue/Saturation dialog (Figure 9b).

An adjustment layer is a mask that has been saved as an alpha channel in the Channels palette. The selections can be made by using Color Range, Quick Mask, or any of the standard selection tools. The advantage of using adjustment layers is that you can experiment to see what happens. If at any stage you are unhappy with the result, it is possible to remove it without degrading the Background layer.

I thought it would be useful to go through this example step-by-step, as a final exercise, so readers can see in detail the techniques and decisions that go into making a selectively colored digital image.


About the Author

Tony Worobiec
Contributor
Tony Worobiec studied fine art at Newcastle University and until recently was head of a large design faculty in Dorset, England. His photography has won awards in the UK and internationally, and has been exhibited in London’s Barbican Gallery and England’s National Museum of Photography. His work has appeared in many photography magazines, and he writes regularly on black-and-white darkroom techniques. He has had five books published, including Beyond Monochrome, Toning and Handtinting, and, most recently, Abandoned America: Ghosts in the Wilderness.