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5.0.0  INK-ON-DRAFTING FILM DRAWINGS

5.1.0  Final sheet lay-out
5.2.0  Inking techniques
5.3.0  Line weights
5.4.0  Drawing on the reverse side of drafting film
5.5.0  Materials symbols for plan poché
5.6.0  Plan process
5.7.0  Elevation process
5.8.0  Section process
5.9.0  Detail process
5.10.0  Axonometric process
5.11.0  Delineating iron and steel structures
5.12.0  Dimension lines
5.13.0  Lettering

5.1.0  FINAL SHEET LAY-OUT

5.1.1  Before inking begins, all elements of the drawings should be composed in order to avoid squeezing notes and dimensions between the images and borders.  Whether the principal image will appear on the sheet vertically or horizontally, composition usually begins by placing it somewhat above the center, since the drawing title and graphic scale will appear below the image.  The Historic American Buildings Survey uses its own preprinted drafting film which must be used for HABS projects, Charles E. Peterson Prize entries, and other documentation produced to HABS standards.  Sheets must be oriented with title blocks on either the right side or the bottom. 

Next, a standard format for dimension lines (distance from the images and from each other) must be determined.  Be sure to consider the placement of section cut indicators and notes in plan. 

Finally, drawing titles, graphic scales, north arrows, plan keys and bodies of text must be positioned on the sheets.  Ideally, text which approaches a paragraph or more in length should first be composed on a word processor, then printed out at the appropriate size for tracing. 
 

5.2.0  INKING TECHNIQUES

5.2.1  One of the hallmarks of an excellent ink drawing is consistency of line weight, that is, individual lines drawn at the same thickness and density over their entire length, and lines which match each other throughout the set. 

Pens should be held lightly, as close to perpendicular to the drafting film as possible.  The drafting film must not be scored; removing ink from scratched drafting film is virtually impossible.  Frequently wiping the nibs on a paper towel will help ensure an even flow of ink.  Lines that fade out or vary in thickness must be redrawn.

As a rapidograph is pulled across drafting film, its ink flow is fairly constant.  So a slowly drawn line will be thicker than one drawn quickly, and at the end of a line, ink still flowing from the pen will tend to form a circular blob.  Therefore, the best method of drawing a clean line--especially .35 (2 x 0) or thicker--is to draw past its designated length, then use an erasing shield to reduce it to its proper length.

5.2.2  Ink is most easily removed from drafting film with a slightly dampened white vinyl eraser.  Care must be taken not to remove the tooth of the drafting surface, and for this reason electric erasers should never be used.  After erasing, wiping the surface with a tissue or chamois is recommended.

5.2.3  Stippling is the technique used to produce textures and the illusion of three-dimensionality.  Depending on the effect desired, pens between .19 mm and .30 mm (4 x 0 and 2 x 0) are used.  Stippling must never be done rapidly!  Each dot must be placed so that it appears round, otherwise numerous tiny streaks will result.  Stippling is usually done on the reverse side of the drafting film; this allows for corrections in density or technique without erasing other features of the drawing.

5.2.4  When using a compass with an ink pen attachment, the compass needle should be set in several layers of drafting tape placed over the center of the circle, but never onto the drafting film itself.  The center may be marked with an ink dot, which is then visible through the tape.  The pen must be aligned perpendicular to the drawing surface.

5.2.5  Inking triangles and templates, or templates with raising bumps, should be used for all ink on drafting film work.  Whenever possible, these tools should be held against a parallel bar, and the bar should be braked or weighed down.

Figure 5.1:  Range of line weights used on a plan drawn at 1/4" = 1'-0".
Note that brick and stone poché stop at the inside surface of plaster finish.

5.3.0  LINE WEIGHTS

5.3.1  The following line weights are used on drawings at 1/4" = 1'-0".

.13 mm  (6 x 0)
Fine ornamentation and detailing; limited texturing and small plant depiction on landscape and site plans; otherwise their size is to be avoided due to poor reproduciblity.

.19 mm  (4 x 0)
Most stippling.  Door swings, stair direction arrows, brick coursing, wood siding, window and door details, window and door frames in plan, floor boards, miter joints, mortise and tenon joints, most ornamentation and detailing; features in the background that would usually be drawn with a larger pen.  Dashed lines indicating features above a cut line, such as roof lines, mantels, beams; in elevation, outlines of windows and doors partly hidden behind other building elements.

25 mm  (3 x 0)
Most drafting lines.  For landscape and site plans: to be used as primary tree indicator in conjunction with .19 mm, .30 mm and .35 mm pens to depict relative heights, densities and species.  Roads on location maps traced from USGS maps.

.30 mm  (2 x 0)
Outlines of openings, door and window frames.

.35 mm  (0)
Edges within perimeter of drawing to show depth in elevation.  Outlines of structures on site plans.

.50 mm  (1)
Wall outlines in plan, major building outline in elevation, section cuts.

.60 mm  (2)
Building outlines for those parts of structure that project forward from picture plane.  This is one technique for showing relative depths.

.70 mm  (2-1/2)
Ground line on sections and elevations. 

Figure 5.2:  Range of line weights used on an elevation drawn at 1/4" = 1'-0", reduced to approximately 1/8" = 1'-0".  Melrose, Natchez National Historical Park, Mississippi.

5.3.2  Drawings at larger and smaller scales will use the above range of line weights, with different maximum and minimum weights.  Also, delineators should learn to produce bold, complex shapes (such as door and window frames in plan) by starting some lines  with a fine pen, then carefully building up to the desired thickness.  See Figures 5.1, 5.2, 5.3 for recommendations.

5.3.3  HABS sheets are transmitted to the Library of Congress without trimming at the trim lines.  Therefore, no extraneous images or "squiggles" should appear anywhere on the sheets.  All pencil marks should also be erased.

Figure 5.3:  Plan inked at 1/2" = 1'-0" shows significantly more detail than one drawn at 1/4" = 1'-0", and requires a greater range of line weights.  Monticello, Charlottesville, Virginia.

5.4.0  DRAWING ON THE REVERSE SIDE
         OF DRAFTING FILM

5.4.1  Stippling, brick courses, floor boards and poché patterns are usually drawn on the back sides of drafting film.  In addition, to depict parts of structures in the distant background (especially in section), other elements may be drawn on the back.
 

5.5.0  MATERIALS SYMBOLS FOR PLAN POCHÉ

5.5.1  Materials symbols are used in plan drawings to depict building materials.  The patterns depicted in Figure 5.4 are identical to those in Architectural Graphic Standards.

5.5.2  Poché patterns are drawn with the same precision as the rest of the image.  The diagonal lines representing brick in plan, for example, should be at 45º to the run of the wall and spaced exactly.  A change in the date of construction, as in the bricking up of an opening, will require a 90º change in the direction of the pattern. 

The poché must also be drawn to match the true thickness of the material.  The lines will be drawn short of the wall edge to depict the finish material.  This is most easily accomplished by drawing through the wall edge (on the back!), then erasing.

Wood frame walls in plan have no poché.
 

5.6.0  PLAN PROCESS

5.6.1  If a structure has more than one level, all plans must be checked against each other for discrepancies between walls, columns and stairs.  Inking a plan proceeds by drawing: 

1) the major walls, columns and other structural elements;

2) doors with swings, other openings, stairs, hearths, historic kitchen appliances and bathroom features;

3) elements above the cut line (indicated by dashed lines) such as mantels, skylights, reflected ceilings, roof lines;

4) elements drawn on the reverse side of the drafting film such as floor boards, floor tiles, spaces and elements seen below floor but above the cut line for the story below, material poché, stippling;

5) dimensions, section cut indicators, stair direction arrows, match lines;

6) drawing title(s), graphic scales;

7) notes, room labels, north arrow.

5.7.0  ELEVATION PROCESS

5.7.1  Each elevation should match all plans, with special attention paid to the placement of openings.  In addition, each section should meet adjacent elevations cleanly at the corners, with special attention paid to matching cornices, quoins, and siding.  If possible, one delineator should be responsible for all repetitive elements (windows, ornamentation) in order to preserve consistency in rendering the character of the structure.  Order of inking:

1) outline of major wall and roof lines;

2) outlines of projections such as chimneys, side porches;

3) forward edges of roof, columns, porches, steps and other elements that project forward from drawing plane; 

4) doors and windows;

5) remaining details, dashed-in indications of elements removed for graphic clarity, as well as partially or totally hidden elements such as basements;

6) ground line;

7) elements on reverse of sheet:  building elements in far background; brick coursing, wood siding, roof materials, masonry and other stippling.

8) If necessary, carefully build up line weights on projecting wings, porches, etc. to increase perception of depth.  For buildings, only wall and roof outlines, as well as porch columns and opening, need be emphasized in this manner.

9) Dimensions, drawing title, notes.

5.8.0  SECTION PROCESS

5.8.1  Section cuts must be checked against plans and elevations--both forward and behind.  The delineator must be sure that jogged sections are properly aligned and can be easily understood.  Drawing proceeds as follows:

1) Draw major cut lines to locate walls, floors, ceilings and stairs;

2) locate roof line;

3) locate slices through roof where section jogs;

4) draw any other elements which are cut, such as rafters and stair rails;

5) complete walls, interior openings beyond the cut, grade line;

6) complete interior elevations (hearths, crown molding, and other architectural details.  Consult with project leader before rendering painted or stenciled ornamentation.) 

7) Draw any elevations attached to the section.

5.9.0  DETAIL PROCESS

5.9.1  Because details are drawn at large scales, it is tempting to use heavier line weights.  However, it is preferable to use the same range as for 1/4" = 1'-0" drawings, then use stippling for texture and shadows when appropriate.
 

5.10.0  AXONOMETRIC PROCESS 

5.10.1  In addition to being dimensionally accurate, axonometric drawings must clearly differentiate among elements in different planes, various materials, and various levels of importance.  A sense of depth can be imparted through the selective use of wood graining; the stippling of stone and masonry for texture; the use of the heaviest line weights at the picture plane and progressively lighter lines as the image recedes.  Following the convention of sunlight falling from the upper left, these techniques can be employed to suggest shading in order to enhance the depth of the image. 
 

5.11.0  DELINEATING IRON AND STEEL STRUCTURES

5.11.1  Historic architectural structures sometimes contain iron or steel building materials and structural systems, often similar to the subjects of documentation by the Historic American Engineering Record. Figures 5.9, 5.10 and 5.11 are examples of bridge drawings, showing a typical elevation, isometric and connection detail.

5.11.2  In the elevation (Figure 5.9), note that showing rivets adds texture to the drawing.  Also, varying line weights on the diagonal bracing adds depth and helps differentiate among structural members.

5.11.3  An isometric (Figure 5.10) best illustrates the construction of a truss-like structure.  The various line weights emphasize the three-dimensionality of beams and truss members.  At this scale, bolt threads are rendered schematically, but not freehand.  Nuts, bolt heads and other parts are drawn as exactly as possible.  Decking and other contextual items are drawn on the reverse side of the drafting film.

5.11.4  In the connection detail (Figure 5.11), shading supplements the dashed lines that show how parts fit together, and adds depth and boldness to this type of drawing.  The steel poché should be used at cut lines.
 

5.12.0  DIMENSION LINES

5.12.1  In determining the comprehensiveness of dimension lines, recorders must anticipate a variety of potential end uses of the drawings (restoration, maintenance, and publication); the complexity of the images; size of the images on the sheets; and type (plan, elevation etc.).  In conjunction with the field notes, HABS ink drawings can convey the same amount of dimensional information as construction drawings.  Alone, their purpose is to present over-all and major element dimensions, as well as style, form, construction history and materials, and existing conditions. 

5.12.2  Plans show the most dimensions.  The minimum required are:  over-alls for all sides; over-alls for blocks, wings, etc.; widths of openings and distances between them. 

5.12.3  Elevations show exterior and interior distances between major vertical divisions:  from finished floor to finished floor; eaves or soffits; cornices; roof ridges and chimney heights.  Unless the grade is relatively solid and permanent (brick or concrete surface), the 0'-0" mark should be the first floor, with running dimensions up and down. 

Both elevations and sections should also show floor to ceiling heights, using incremental dimensions. 

5.12.4  Ornamental details usually require only over-all dimensions because they are best recorded photographically with scale sticks.  Construction details may be shown with a combination of dimensions and notes calling out nominal/actual sizes of generic materials. 

5.12.5  In plan, the first dimension line (rough openings) is typically drawn 3/4" to 1" from the image, and successive lines are 3/8" apart.  The distance indicators should approach, but never touch the image.  A dot (.70 mm or .80 mm pen) is placed at the intersections.  The lines should be constructed uniformly throughout the set. 

5.12.6  For elevations and sections, dimension lines should be located far enough away from the image to accommodate one or two-word notes, typically 1-1/2" to 2".
 

5.13.0  LETTERING

5.13.1  The HABS standard for inking text is either use of the Leroy or similar mechanical lettering system, or neat, consistent and unadorned hand-lettering.  The use of "stickyback" or other types of press-on lettering is not acceptable. 

The preferred style for all text, notes and dimensions is sans serif or "helvetica."  Large, open-face, serif templates are used on title sheets.  Only capital letters are used except to pluralize a date ("THE 1990s").  Because drawings are always reduced for transmittal, publication and microfilming, all lettering must remain legible when reduced.  Text blocks are usually justified with the aid of a word processor; font sizes correspond to the Leroy templates:  24 point = 240 template, etc.  If a word must be hyphenated, its syllabication should be checked.  Words are not divided if two letters remain standing alone, or if they are proper nouns.

5.13.2  Lettering should be practiced well in advance of inking the drawings.  The delineator should hold the scriber lightly, keeping his eye on the pin in the groove, rather than on the actual letter being inked.  If text is being inked without a printed underlay, careful attention must be paid to even spacing between letters and words.  Consistent line weight and crispness of the letters is as important as precise drafting of the images. A useful skill is the ability to letter backwards; when lettering dimensions on elevations and sections, inking from right to left will aid in aligning the text.

5.13.3  Recommended mechanical lettering template sizes:

240 (1/4")
Name of structure in title block.
Name of drawing. 

175
Drawing subtitles, room labels with dimensions.  Statement of significance, project information for 33" x 44" sheets.

140
Dimensions, materials lists and other notes. Statement of significance, project information for 24" x 36" sheets.

120 (1/8")
Scales, title block information, name of delineators.
UTM information on location map.

100
Place names on location map.
 

Figure 5.6:  Reduction of a section/interior elevation through the dome of the Texas State Capitol, Austin, Texas.  Blank areas indicated by arrows can not be recorded by conventional methods.
 

Figure 5.7:  Isometric, upward view.  Texas State Capitol, Austin, Texas.
 

Figure 5.8:  Cutaway axonometric drawing of the Maryland State House dome, Annapolis, Maryland, showing the heavy timber structure, cladding, and interior elevation.

Figure 5.9:  Elevation of a truss-like structure.  Zoarville Station Bridge, Zoarville, Ohio (HAER).

Figute 5.10:  Partially exploded axonometric of a bridge truss,
showing the use of several line weights to help distinguish the various elements.
Sockman Road Bridge, Fredericktown, Ohio (HAER).

Figure 5.11:  Dilineation of metal connection details.
Zoarville Station Bridge, Zoarville, Ohio (HAER).

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