Tidbits of the Digital Chicago Method Part 7 – Introducing the Survey's New Sun-Shadow Brushes

Jan 14, 2021

Written by Krisztián Vértes

The Epigraphic Survey's basic brush stroke sizes as set up for their standard 1200 dpi digital inking environment

Designed to provide continuity with their traditional Rapidograph ink art, the Survey's digital brushstrokes haven't seen any significant update since 2013. Nonetheless, minor corrections were applied to the basic set, mostly adding extra pixels to dotted lines and texture brushes, creating a more prominent appearance for strokes rendered by rapid repetitive brush movement. Painted lines, surface modeling, damage, and plaster textures are now inked with 7-pixel brush-width. In contrast, damage texture is indicated by a custom bristle paintbrush produced for a faithful damage replication that has the same non-uniform appearance as our traditional ink-pen. Further changes include a refined dashed line to better indicate architectural features and the complete overhaul of how brushes are saved, including their color, size, and tool settings. These improvements help the artist focus more on the actual drawing process, even when working digitally.

However, innovation can never stop as long as there can be a better, more comfortable way provided for the artist to facilitate digital inking! In this new tutorial of the Survey's "Tidbits…" series, digitalEPIGRAPHY would like to focus on one of the focal points in rendering raised and sunken relief, namely sun-shadow transitions. Drawing aesthetically pleasing linewidth transitions applying a dynamically changing brush stroke can be quite difficult. However, with the alternated use of drawing freehand with Photoshop's brilliant Brushstroke Smoothing Tool and laying down paths with the Curvature Pen Tool, one can have the necessary "superpower" to reach near perfection. 

Drawing freehand, adding a sun-shadow transition to a curved outline with the assistance of brushstroke smoothing for stability

While both of these aids help tremendously, perfecting these techniques remain challenging. Alternating between repeatedly laying down, moving, stroking paths, or turning assisted drawing on and off several times with each sun-shadow rendering can be off-putting for the artist seeking an elegant way to shift from traditional to digital art. One of the burdens of such methods is the constant switching between different brush sizes. If only we could have a brush that "knows" when to paint thicker or fade into a thinner variant, it could be a serious time-saver for the inking process. Of course, such an intelligent brush will never exist unless a programmer writes an algorithm specifically designed for digital epigraphy. In the meantime, we took a closer look at Photoshop's Brush Settings (Window/Brush Settings) and started playing with various attributes concentrating on one specific feature, called Shape Dynamics.

Shape Dynamics in Photoshop Brushes

To access the Shape Dynamics options, one has to open Brush Settings with one of the Survey's brushes selected and click on the actual name on the left (clicking the checkbox will only turn the option on but won't provide access to the controls). Once active, Shape Dynamics should display several choices on the panel's right side, grouped under three main categories called Size Jitter, Angle Jitter, and Roundness Jitter. There is a preview area on the bottom of the panel, so we can see the effect we're having on the brushstroke as changes are made.

Shape Dynamics allows the artist to dynamically control the size, angle, and roundness of the brush in real-time 

Below each of the three headings is a Control option tied directly to the title above it. The selections in their drop-down menus give us various ways to dynamically control the brush's size, angle, and roundness as we paint. Of course, most of these dynamic behaviors require the artist to interact with a pressure-sensitive tablet. For our purpose, we should have a closer look at the Size category.

The Size section provides exactly what we need for sun-shadow transitions by offering different ways to change the brush stroke's width as we paint dynamically. To see a list of all the various ways we can choose to control the brush size, simply click on the drop-down list to the Control option's right. Let's quickly describe each choice:

  • Fade - gradually reduces the size of the brush as the pen is dragged across the canvas.
  • Pen Pressure - the harder the pen is pressed onto the tablet, the thicker the stroke becomes.
  • Pen Tilt - with all the pressure-sensitive capacities of the Pen Pressure option included, it adds the ability to control the brush's size by tilting the pen as you paint. The further the pen is tilted, the larger the stroke becomes.
  • Stylus Wheel – with pens like Wacom’s Airbrush Pen, brush size can be controlled using a wheel found on these particular styli.

We should also have a few words about how Photoshop brushes work for you to better understand the specific settings we’re about to use. When you paint on paper using traditional media, your brush lays down a continuous layer of paint with your stroke getting thinner and less intense as the brush “empties.” When painting digitally, Photoshop “stamps” a series of brush tips along the brush's path as dragged on the canvas. The way it works with Shape Dynamics is that – for example – with Fade selected, Photoshop gradually reduces the stamp size with each consecutive iteration until the brush is no longer visible. 

Exactly how long it takes for the brush stroke to fade out completely is determined by the number of steps we set for it in the input box to the Control option's right. The default number of steps is 25, which means that Photoshop will gradually reduce the brush stroke's size from its original size to zero throughout 25 succeeding stamps. 

The exact nature of how a brushstroke “fades out” is determined by the number of steps and the minimum diameter

There is yet another option to fiddle with to specify our dynamic brush stroke's behavior, called Minimum Diameter. This slider sets the limit for how small the brush will get as it fades out. Naturally, when it is set to 0%, it fades out completely. However, when this number is higher than zero, once the fading reaches that percentage, it will remain at that size for as long as you continue dragging out the stroke. As expected, the minimum diameter's value can be adjusted either by adjusting its slider or by entering a specific value into the input box. When the number is increased to any percent but zero, the brush stroke's preview at the bottom of the panel will reflect this behavior, showing that it continues without dropping below its new minimum size.

The new sun-shadow brushes designed for digital inking

The Epigraphic Survey’s new sun-shadow brushes designed for 1200 dpi environment come in three sizes (Full, Medium, and Fine) to be suitable for a wide range of use cases

Let’s see how these options can be tweaked to provide the ideal variant for inking sun-shadow transitions in the Survey’s standard digital inking environment. First, we need to establish the starting line weight of the new dynamic brushes. To better reflect the many different shadow line weights appearing on our drawings (ranging from deeply carved Ramesside hieroglyphs to the most delicate internal details), we came up with three basic variants. These are called Sun-Shadow (full), Sun-Shadow (medium), and Sun-Shadow (fine). Full starts with a 20-pixel diameter (the equivalent of the Full-shadow brush). Similarly, medium has a 15 pixel width (between the Half-shadow and Light-shadow brushes), and finally, fine is 10 pixels wide at the start that is the equivalent to the Sun brush. 

The idea behind setting up these specific numbers is not to use the sun-shadow brushes to provide the exact transition with just a swoosh of one single brush stroke but rather to build up the relevant effect with a gentle sequence of repeated strokes. Therefore, one should never consider creating a 20-10 pixels sun-shadow transition by applying the Sun-Shadow (full) dynamic brush. This brush being 20 pixels wide at the start will prevent the endpoints from joining seamlessly with the rest of the line. Instead, the artist should always use a dynamic brush that starts lighter (aka thinner) than the actual shadow weight while gently building up the necessary line weight. 

With the basics established, we should get back to tweaking the fading-out effect by setting the steps and the minimum diameter. For obvious reasons, there can’t be a single dynamic brush design that always fades out precisely as a particular sun-shadow situation requires over an actual curve. Therefore, instead of designing a large number of slightly modified brushes (that would most certainly slow down the inking process), digitalEPIGRAPHY set up a brush length (the number of fade-out steps described above) that works in most situations. We determined the length in 200 steps and the minimum diameter (the limit for how small the brush can get) at 20%. It means that when the Sun-Shadow (Medium) brush is used, the artist starts with a 15-pixel brush-width that gently fades out within the length of 200 consecutive iterations and will remain three pixels wide until the stylus is lifted.

Utilizing Photoshop’s latest refinements, the new brushes come with their size, color, and smoothing behavior preset. If you'd like to download the Survey’s newly designed sun-shadow brushes and give them a try, you can do so by clicking on the following link. Nonetheless, we’d like to encourage you to design your dynamic brushes tailored to your projects using the above principles. To see the new brushes in action, please, watch the video tutorial below.

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