Zoosyst. Evol. 94 (2) 2018, 529-533 | DOI! 10.3897/zse.94.28624 > PENSUFT. Cnt BERLIN Shadings in digital taxonomic drawings Ch. Oliver Coleman! 1 Museum fiir Naturkunde, Invalidenstrafe 43, 10115 Berlin, Germany http://zoobank.org/3 CE03C4E-D8B8-4EB 1-AAOF-FO9FFE1LED04D Corresponding author: Ch. Oliver Coleman (oliver.coleman@mfn.berlin) Abstract Received 25 July 2018 Accepted 14 August 2018 Published 22 November 2018 This contribution describes how shadings can be applied to taxonomic line drawings cre- ated with vector graphics software. The line drawings created with the vector graphic software are saved in vector format and then also in bitmap graphics format. The bitmap version is opened in a bitmap graphics program and the areas for shading selected. A new Academic editor: Michael Ohl layer is then created and clouds of pixels are ‘sprayed’ onto these areas. The pixel clouds are saved and later placed onto the outlines in the vector graphic software as a new layer. The results combine the advantages of vector graphics, perfectly smooth lines and the Key Words Taxonomy digital illustration drawing shading Introduction Photography is often used in taxonomic descriptions and works especially well for larger animals. When using a Stack of pictures it is possible to combine them with software into one photo of excellent depth of field (for example with CombineZP: http://combinezp.software. in- former.com). But for small, translucent animals stacking does not work as well and many details remain invisible in the photo. Here, drawings are still the best choice for a taxonomic description. The use of computers for taxo- nomic drawings helped to speed up the documentation and at the same time improve the quality of these line drawings. Compared to the traditional use of ink pens the digital drawing method has advantages: e.g. corrections are easy, it 1s possible to create complex structures like setae in an elegant and rapid way and the arrangement of plates is quickly achieved (Coleman 2003, 2006, 2009). greyscales of bitmap graphics. Montesanto (2015, 2016) used bitmap graphic solutions for taxonomic drawings, e.g. GIMP, but the quality of bitmap line drawings as proposed in these papers is in- ferior compared to vector graphics and the scaling of detailed drawings during the arrangement of plates leads to different line weights. However, bitmap graphics have a great potential when greyscale information is needed, for example for shading. Shading is especially helpful for showing cuticular structures such as carinae, teeth or grooves. However, vector graphics are superior to bitmap graphics in several respects for pure line drawings. The idea of shading directly within vector graphic software was proposed by Bober and Riehl (2014), but was adopt- ed in only a few papers. In the present paper it is shown how to combine the best of these two technologies in the same drawing: the high-quality smooth lines created by vector graphics like Illustrator, and greyscale bitmap shading with Photoshop. Copyright Ch. Oliver Coleman. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 530 Material and methods Pencil drawings, made with a Leica DMLB microscope equipped with a camera lucida, were scanned with a DINA3 scanner (Plustek Optibook A300) as a template. Several scans of a large pencil drawing can be combined into one template within the vector graphics software pro- gram Adobe Illustrator CS2, which was used for this paper, subsequently using the “Place” command for combining parts of the scans. Alternatively photos can be used as a master (Coleman 2006). The bitmap program Adobe Pho- toshop CS2 was used to generate the pixel shadings. The method should work in an analogous way with other simi- lar software products. A Wacom Bamboo graphics tablet was used for creat- ing line drawings in Illustrator as well as for shading in Photoshop. Step-by-step instructions e The starting point for shading is ideally a plate with a habitus drawing on it, opened in Illustrator. On the ar- Export SynopiidenDLT-230kt_2014 WridAmphipodFamilies Color Model: ig Resolution Screen (72 ppi) ( Medium (150 ppi) f High (300 ppi} ( Other: | 150 ppi — Options Export As: [Photoshop Coe bd (* Flat Image ( Write Layers J¥ Preserve Text Bditability T | Maximum Editability |v Anti-alias . Embed |Ge Profile B Coleman, O.Ch.: Shadings in digital taxonomic drawings ranged plate the habitus drawing is already at the right size and the density of pixels in the shadings can be best controlled in the final format. From within Illustrator, export the plate into Photo- shop format (.psd). Select “Flat Image” in the Photo- shop Export Options (Figure 1A—B). Minimize IIlus- trator and then continue to work in Photoshop. Open the file with the line drawings in Photoshop (File-Open or double click on the file name with a psd-extension). Limit the areas which should be shaded using the “magic wand” tool (Figure 2A). If needed, select sev- eral areas at the same time by holding the “shift” key while clicking inside the designated areas. If every- thing works correctly, the inner margins of the outlines then appear fuzzy. If the box margin of the picture be- comes fuzzy instead, then the areas are not completely closed by a continuous line. The selection of areas has to be done on the layer that contains the outlines of the habitus (the first layer) (Figure 2B). Figure 1. A) Export plate from Illustrator into Photoshop format (.psd). B) Use “Flat Image” option. zse.pensoft.net Zoosyst. Evol. 94 (2) 2018, 529-533 40) Normal =] Opacity: [100% [> ] tock: a @ rit: [100% [>] = ayers (r) [Normal ea | ‘Opacity: Lock: Lf + @ Fa: [1009 [* ] ° J ested 53:1 Pas k ss | } | = go) | [Normal * ] Opacity: [ 10036 | + | tock: Oy + 1 [100% [* | CUle7 C8 B&R DE eM \» - a a {s] s|o sie ™ Eile Edit Image Layer Select Filter View Window Help \\[4F] | Brush: FAR | Mode: [Dissolve + ] Opacity: | Flow: EA | Master Diameter Set the diameter for the primary brush and scale the dual brush al > Figure 2. A) In Photoshop use “Magic Wand Tool” and the “shift” key to mark areas in the drawing for shading. B) Create a new layer, by clicking on second icon from the right in the icon bar at the lower end of the window. C) Select the newly created layer before applying the shading. D) Select “Brush”, modify “Master Diameter” and set “Flow” at about 3-4%. ¢ Create a new layer (by clicking on the second icon’ « There are two options: 1) “Mode: Normal” for grey- from the right in the icon bar, marked as “Create new layer”, below in the “Layers” window, see Figure 2B). It is essential to apply the shadings only to this newly created layer (Figure 2C)! Select the “Brush” (B) tool, and then in the Brush dia- log (settings bar, upper left corner, below File and Edit pulldown menu) “Airbrush Soft Round”. Adapt the Brush size by moving the “Master Diame- ter” lever (Figure 2D). scale or 2) “Mode: Dissolve” for stippling (creating a pixel cloud). Keep “Opacity” at 100%, the setting for “Flow” should only be at 3-4% (Figure 2D), in order to prevent too many pixels being sprayed. Foreground colour must be black. Spray pixel clouds with the mouse or the Wacom board. If everything was set up correctly the pixels will only appear inside the selected areas (Figure 3A). zse.pensoft.net 532 Coleman, O.Ch.: Shadings in digital taxonomic drawings LL i4)[ DB 4) Default Actions * #7 Layers M0} a[ [Normal = | Opacity: [ 100% |» ] 2“) ick Oo @ Fil: [100% [> ] Figure 3. A) In Photoshop select newly created layer and apply shading by spraying pixels onto selected areas. B) After airbrushing, make first layer, containing the outlines, invisible by clicking on eye icon in “Layers”. By this only the pixel clouds are retained. ¢ Ifsome areas appear too dark, change “Set foreground colour” to white by clicking on the double arrow close to the white and black squares in the Tools. Then spray white pixels on top of the black pixels. ¢ In order to get an idea about the right density of the shadings, print out the file from time to time. The den- sity of the pixel clouds in the printout may differ from what you see on the screen. ¢ When you are content with the result, make the layer that contains the outlines (the first layer) invisible by clicking on the eye symbol beside the first layer unse- lecting it (Figure 3B). ¢ Then save the Photoshop file, which now only contains the shadings, but not the outlines (Figure 3B). ¢ Expand the minimized Illustrator drawing, create a new layer and place the Photoshop file with the pixel shadings onto the habitus using the File-Place dialog. Carry out fine adjustments with the cursor keys (or simultaneously hold “shift” and use the cursor keys, for faster movements) (Figure 4A—B). zse.pensoft.net Discussion Coleman described in a series of papers (2003, 2006, 2009) how to use Illustrator for taxonomic drawings. These three papers show how to produce high quali- ty vector drawings both quickly and accurately. The only part that was missing in this series of publications is shading. Shadings in vector graphics work theoret- ically (Bober and Riehl 2014), but the results are not very convincing. During initial trials with Photoshop (Coleman 2003) a whole plate was exported into bit- map format prior to shading, leading to the loss of the vector information and thus rough lines. In the method proposed here, however, the vector graphics are un- changed and only the bitmap shadings are placed as an overlay on top of the vector graphics. In this way the advantages of vector graphics (perfect, smooth lines) and the greyscale and stippling capabilities of bitmap graphics are combined, leading to a final image of su- perior quality. Zoosyst. Evol. 94 (2) 2018, 529-533 533 B Figure 4. A) Place pixel cloud, saved without outlines from Photoshop into Illustrator using the File-Place command. B) Move the pixel cloud in the corresponding areas of the vector graphics in I]lustrator. Acknowledgements The author likes to thank the two reviewers for their very useful comments that helped to improve the manuscript. Thanks also to Dr. Jason Dunlop (Berlin) for improving the English language. References Bober S, Riehl T (2014) Adding depth to line artwork by digital stip- pling — a step-by-step guide to the method. Organisms Diversity & Evolution 14(3): 327-337. https://doi.org/10.1007/s13127-014- 0173-7 Coleman CO (2003) “Digital inking”: How to make perfect line draw- ings on computers. Organisms Diversity & Evolution, Electronic Supplement 14: 1-14. Coleman CO (2006) Substituting time-consuming pencil drawings in arthropod taxonomy using stacks of digital photographs. Zootaxa 1360: 61-68. Coleman CO (2009) Drawing setae the digital way. Zoosystematics and Evolution 85: 305-310. https://doi.org/10.1002/zoos.200900008 Montesanto G (2015) A fast GNU method to draw accurate scientif- ic illustrations for taxonomy. Zookeys 515: 191—206. https://doi. org/10.3897/zookeys.515.9459 Montesanto G (2016) Drawing setae: a GNU way for digital scientific illustrations. Nauplius 24: 1-6. https://doi.org/10.1590/2358- 2936e2016017 zse.pensoft.net