Documenting painted decorative surfaces – Digitally resurrecting a traditional color pencil drawing technique using Photoshop

Mar 25, 2019

The following article is going to be a somewhat unusual tutorial as it is aimed to give the reader a sneak-peek into the process of developing a new documentation method. Eventually, all the articles appearing in this series will be tied together within a single case study of a color enhanced drawing sequence based on the Ramesside square pillar, MHB 125, at the Small Amun Temple in Medinet Habu. In this first installment, digitalEPIGRAPHY would like to show you how to take a traditional drawing medium, such as color pencil, and turn it into a digital Photoshop toolset appropriated for documenting larger surface areas, while opening a whole new range of possibilities. The sample drawing used in the forthcoming tutorial is a color pencil representation augmented over MHB 95, a Thutmoside raised relief square pillar face with minimal paint preservation. As the preservation of painted details on all these pillar faces is very poor, the Epigraphic Survey decided to complement the photographic and line drawing documentation with a series of color pencil studies. Started in 2011, the idea was to create a graphical representation of all the pigment traces that can be recovered from the surface. The drawings, created by using Derwent Artist color pencils on matte acetate paper (mylar), were scanned and color corrected afterwards, in preparation of being published in the Survey’s forthcoming publication, Medinet Habu Volume X.

MHB 95 shows faint traces of the original painted design peeking through a thin layer of plaster cover.

While delivering satisfactory results, using a traditional medium to create these drawings also delineated several difficulties. To avoid distortion, the original bleached enlargement holding the Rapidograph line drawing was used for specifying the context of the color pencil texture. As expected, restoring the precise alignment between enlargement and mylar after digitization was challenging. Furthermore, the matte acetate had its own color and texture that played an important role in establishing the relevant pencil hues, an aspect which needed to be preserved. Subsequently, color calibration, distortion correction and layer modification needed to be done for each of these drawings during postproduction. Another difficulty arose from the very nature of the Chicago method: after the inked drawings were bleached, the photograph wasn’t an integral part of the process anymore. Therefore, when creating the color enhanced drawings, the artist had to approximate the painted details based on looking at the wall while trying to find the exact placement on a reduced line drawing. 

Shaping the digital Derwent Artist set

As the Survey started implementing digital techniques into their documentation process, it became clear that turning towards computer technology would be tremendously helpful in eliminating the above complications and extending the color studies over much larger surfaces. After experimenting with several software solutions, both on the iPad and the Mac, only the usual contenders remained still standing: Procreate, Affinity Designer and Adobe Photoshop. Our initial aim was to work with a native iPad App, for that reason Procreate would have been an ideal choice with its versatility and lightweight UI, while Affinity Designer would have provided more complex toolsets. However, the high-resolution digital background created for MHB 125 would have had to be altered significantly to be used with either Procreate or Designer. Such a large and detailed color background would have to be downscaled significantly or divided up into much smaller sections, even for Apple’s powerful new Pro tablet. As these options would have meant too many compromises, we decided to keep the file at its original 1200 dpi resolution and turn towards Adobe Photoshop to create our digital Derwent Artist pencils. 

Drawing color samples on mylar for each hue that was applied on the enhanced color pencil drawing, MHB 95.

Because each painted hue on MHB 95 was represented as a mixture of 2 or 3 individual color pencil textures, many different aspects of the original needed to be taken into account when designing the appropriate digital pencils. First, sample areas of each color pencil hue were drawn on mylar using the same texturing technique developed for MHB 95. The Derwent Artist pencils applied for the Medinet Habu color enhanced drawings were the following: Golden Brown (5900), Mineral Green (4500), Storm Grey (6910), Scarlet Lake (1200), Kingfisher Blue (3800), Bright Red (1410), Crimson Lake (2000), Ivory Black (6700), Prussian Blue (3500) and Chinese White (7200). One color pencil was provided by a different company: Dark Brown (946) made by Berol Prismacolor. As we stated above, to be able to offer the necessary range of color transitions when imitating the actual pigment preservation of the wall, we always had to apply a certain combination of these color pencils. The most common combinations (indicated by their numbers) within a specific color range were as follows: yellow (5900+946), red (1200+1410+946), purple (2000+946), green (3800+4500+946), blue (3800+3500+946), black (6700), white (7200), Thutmoside background (3800+6910) and Ptolemaic background (5900+6910). Once the samples were created for each pencil hue, the mylar sample was scanned at 1200 dpi RGB, following the exact procedure applied on the MHB 95 color enhanced drawing back in 2011.

The digitized Derwent color pencil samples ready for Photoshop (left) and details shown at 100% (right).

As we enlarge the digitized pencil sample to its maximum zoom level, we can see the fine color transitions within each hue, the certain amount of transparency occurring when strokes are applied over and over on the same area, the specific texture that is provided by particular Derwent pencils used for this project and the varied width of each pencil stroke based on how sharp the pencil was at the moment of drawing these rectangles. There was no digital pencil we could find that would satisfyingly replicate all these attributes, therefore the digital pencils for the Medinet Habu project needed to be designed from the ground up. As you can judge based on the slideshow below, we spent a significant amount of time tweaking the settings for the digital Derwent color brush before we reached the point when it started to look and behave similarly to its traditional counterpart. Shape Dynamics and Scattering needed to be altered to get the desired pressure sensitivity and variability for the pencil stroke, while we had to find the right texture for the brush as well. Among other changes, when putting on the final touches, we also applied a specific brush setting digitalEPIGRAPHY has already raved about, called Dual Brush.

The digital Derwent Artist Brush

Getting the right color for the digital brushes

Color Picker showing different results in Photoshop based on the actual pixel selected.

With the digital pencil brush shaping up, it was time to turn towards color calibration. As can be seen on the above photo, the Color Picker in Photoshop (and as a matter of fact in all digital drawing software) is pixel based, which means that one can’t just have the exact hue provided for a digital pencil by clicking on a scanned pencil stroke. The Color Picker will provide a slightly different hue each time you hit the scanned image based on the actual pixel selected and none of those hues will assign the right color to your brush, no matter how hard you try. Additionally, we must keep in mind that the scanned pencil strokes were originally laid out on matte acetate which means that these semi-transparent digital pencil strokes would provide strikingly different results without the original matte acetate background. An obvious solution to eliminate this issue was to scan a section of our mylar and create a 1200dpi pattern based on the scan. Once created, a layer (set to Multiply to let the layer below show through) can be set up above any digitized or digitally created line drawing. When this layer is filled with this pattern, it provides a semi-transparent digital mylar for the digital Derwent brush. Again, this analogy came from the traditional method used for MHB 95, where the line drawing was attached directly underneath the mylar while creating the color pencil drawing. Regarding the Color Picker problem, finding the right color was relatively straightforward: we just had to play with and tweak the hues for long enough using the color palette Photoshop provides... As soon as both digital mylar and the right color took effect, the newly designed Photoshop pencil brush became indistinguishable from the original.

The scanned color pencil sample extended with newly designed digital pencil brush strokes.

However, there were a few more things to take care of. Each digital Derwent color pencil had to be saved with their attributes, including brush size, tool settings and color. Eventually we recreated the exact same individual color pencils we used in the past in a digital “pencil holder” in Photoshop. Along with the relevant brushes, their hues were also saved in a Photoshop Swatch set and stored for future reference. Finally, a special Color Mixer Brush was created to tone down the sharpness of the color pencil strokes whenever necessary, creating the total illusion of working with traditional mediums. The new brushes were tested out over a sample section of the MHB 95 line drawing, which was then compared with the original. 

One could ask at the end: why would we go to such great lengths to digitally replicate a medium that is readily available and already proved to deliver the desired results in the past?! Transforming a traditional tool to be used in a digital environment provides not merely a cleaner environment for publication (eliminating the need for scanning and color calibration) but opens a whole new set of possibilities as well. What we created for this tutorial is just the first step in extending a consistent color scheme over much larger surfaces, eventually over entire temple walls. In our next installment we’ll show you how to create Photoshop patterns based on the newly designed digital Derwent color brushes and will start building up the entire ecosystem that will be necessary to extend our work beyond what was possible in the past. You can download our Derwent digital pencils (including the Color Mixer Brush) from here, the Matte Acetate background pattern from here and the Derwent color swatches from here for your own pleasure, but you should keep in mind that they only work in Photoshop on a 1200 dpi RGB canvas. If you wish to practice on a “real” line drawing, you can download the MHB 95 digital sample used for this tutorial from here.

For its final appearance, our digital pencil test drawing received a slight Levels adjustment.

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