Tuesday, January 13, 2015


The start of the first interpretative line drawing for the monograph. Photograph by John Scannella.

January 13, 2015

For the past several days a migraine headache has stopped me from making daily updates to this diary, but it has now receded. In the meantime, I've made all of the revisions to the monograph, where features could be seen in lateral view. The manuscript is 1,269 pages in length.
Late last week I reached an important milestone, namely the interpretive line drawings of each bone. Although photographs are a straightforward approach to illustration, they are unable to capture subtle features or the difference between a pristine surface and damage, and their value is diminished when they are defaced by labels and leader lines. Therefore, it is ideal to have accompanying line drawings in a formal description that map out all of the features that are not obvious in a photograph and show all that are discussed in the text.
This time around, I am making each line drawing by tracing the photographs that will make up the plates in the monograph. I crop each image in photoshop and adjust the size (maximum fit to an 8.5 x 11 page) and dpi (300) before reorienting them and converting them into pdf files in illustrator. Once printed, I then tape onto the paper a sheet of acetate, the sort used for overhead transparencies. I then put the sheets on a clipboard and start the drawing using various calibers of black pens (Prismacolor, black ink, caliber 0.8-0.01).
Since I have less than three weeks to make hundreds of drawings, I am using acetate to save time; when time is not an issue I usually use parchment paper and I trace the images on a light board first in pencil, and then I ink the line drawing afterward. During this visit I can’t afford to waste time on two steps.
The main challenge with this process is that it takes a long time for the ink to dry on the acetate, and the finest lines may bead up to produce a faint or irregular line. The faint lines mean I have to go over some areas twice, but the wet ink is the larger problem. Many of those problems can be fixed digitally, but my preference is to make clean, sharp drawings that require a minimum of additional work. In addition to that, the acetate sheets are packaged with thin sheets of parchment paper that separate them; I use a sheet of parchment as a guard so my hand does not rest directly on the acetate and smudge the ink. However, smudging was not completely prevented on my first image (the skull in left lateral view), which shows that I need to take more care and plan out where I start on each drawing. I am happy to report that I've since solved that problem.
For line drawings, I follow a few straightforward rules:
1) Every line and dot must have meaning; i.e., each one must correspond to a feature that is seen on the specimen.
2) In keeping with convention, weight the lines in accord with illumination from the upper left.
3) Unite the entire image with a medium weight tie line and vary the line weight with the illumination; put the thickest lines along the edges of structures that are closest to the viewer; progressively thinner lines must correspond to progressively distant structures; unite each fenestra with a medium weight tie line and vary the line weight according to the source of illumination; solid lines pertain to edges whether or not they are free or overlapping, or pertain to broken surfaces, unprepared matrix, glue, or plaster; use dots are used to mark boundaries of nonoverlapping topographical structures (e.g., the edge of a fading sulcus).
4) Pay more attention to the specimen than to the drawing; i.e., double and triple check between the specimen and the image that the line you are drawing actually matches reality.
The first image - cranium of the subadult in left lateral view - completed! In the right foreground are the bound hard copies of the Two Medicine tyrannosaurine monograph (back when it was a mere 627 pages) and the Jane monograph. They are stacked together to give an approximation of the 1,269 behemoth that the tyrannosaurine monograph has reached. By the way, they are printed with two pages on each sheet to conserve paper!

1 comment:

  1. That is a relief. Glad to know that your migraine headaches are less of a hindrance now. Something like those shouldn't get in the way of design, much less study, so the quickest you can be rid of them, the most welcome indeed. Thanks for sharing that! All the best to you!

    Agnes Lawson @ Pain Relief Experts