TECHNICAL ILLUSTRATION DEFINITIONS PHRASES: A to Z

Alphabetical Definitions Listing:

Acetate:
a transparent plastic sheet material with a number of studio uses, e.g. for masking airbrush work for colour overlays.

Acrylic:
paints made with a synthetic resin base which can be diluted with water and have the properties of being quick drying and sustaining colour values.

Airbrush:
an instrument for applying ink or diluted paint in the form of an atomized spray of colour by combining the medium with air under pressure. Typically the colour spread is even and can be subtly graduated.

Art board:
a general term for rigid paper materials used as supports for painting and drawing. There is a wide range of weights and textures. CS2, CS10

Artwork:
original illustration and other types of graphic material presented in a form suitable for reproduction.

Axis:
an imaginary line representing the linear centre of an object or image. This describes the angle or direction of an object in relation to the viewer in a perspective view and divides an image symmetrically or with equal balance around the axis.

Axonometric:
the plane view provided by the orthographic information remains parallel to the picture plane, so true measurements can again be used in scale. Vertical lines remain vertical, but the construction appears tilted forward from the ground plane.

Background:
broadly, the area surrounding the central subject or focal area of an image, which may describe the real or apparent space or a specific location.

Bleed:
in graphic design, the extension of an image over the outer boundaries of a design grid, an illustration taken across the margins of a book page.

Brief:
the instructions given to an illustrator or designer for executing a specific commission. For the illustrator this should specify subject matter, style and the form of presentation required (line or full colour) and also the fees and deadlines for the work. It may also include provision of reference material or contacts for technical advice.

Cross section:
a diagrammatic or fully realized rendering of an object showing it as if cut right through, usually at right angles to the main axis.

CS10 Art board:
the original supreme fine surface board for illustration airbrushing by Frisk, London.

Cutaway:
an illustration showing an object with a section cut out or with an outer casing partially cut away to reveal internal parts.

Drafting film:
a semi-transparent sheet material of similar weight to heavy paper, used as a drawing surface particularly for ink line work.

Dry brush:
a technique of creating a dragged or broken paint texture by charging the brush with colour and blotting it off before applying the residue of paint.

Elevation:
a diagrammatic view of an object showing a vertical projection of one side only.

Ellipse guides:
a range of drawing guides (Leitz Timely) normally ranging from 10 to 80 degrees and from 2mm to 60mm in diameter, for producing accurately constructed ellipses, using perspective drawing axes.

Exploded View:
an illustration showing an object disassembled with the parts aligned in correct relation to one another along the main axes of the construction.

Finished artwork:
final finished artwork provided to a printer or client, after the pre-press approval process. Including all marked up copy and detailed instructions for image reproduction.

Foreshortening:
the perspective effect of recession in which there is apparent distortion of the normal proportions of an object: parts closest to the viewer may appear very large and those furthest away relatively much smaller and the distance between them telescoped down by comparison with the actual dimensions.

Format:
the dimensions and proportions of an illustration, or of the graphic representation in which it appears, a book page or wall chart.

Four colour process:
the method of printing in full colour by scanning an image to produce half tone plates in four colours as yellow, cyan, magenta and black, which when printed together reproduce the original colour effects.

Ghosting:
the convention in technical illustration of showing interior components or mechanisms of an object as if seen through the outer layers.

Glaze:
a thin layer of transparent colour. Usually refers to oil paint diluted with turpentine or oil, water diluted acrylics can produce the same effects.

Gouache:
paint (water soluble) consisting of pigment in a binder together with a filler substance which gives the colour opacity.

Grain:
the texture of a paper surface resulting from the fibres in its composition and the method of finishing used in manufacture.

Grid:
a measuring guide used to structure an illustration or design. A printed or drawn perspective grid may be the basis of an accurate drawing for a technical illustration. In design work a grid is made to page format and sets the framework for positioning type matter and illustration.

Ground:
a prepared surface for painting and illustration work.

Half tones:
patterns of dots or lines simulating solid areas of varying tones.

Hatching:
the method of producing tonal values, mixed colours or textural effects in drawing or painting by filling an area with parallel lines rather than solid or blended colours.

Highlights:
the lightest tonal or colour values in an image, describing any point or area where the maximum amount of light is reflected from a surface.

Hot pressed:
a smooth quality of paper surface created by heat processing in manufacture.

Hue:
the intrinsic value of a specific colour, red identifies a certain type of colour but includes a variety of hues ranging from orange red to purple red.

Ink:
a liquid medium for drawing or painting available in black, white and a range of colours. Certain types of drawing ink are formulated to be completely waterproof when dry.

Isometric:
non-perspective means of constructing a three dimensional view based on orthographic information. An isometric view employs vertical lines and receding axes at 30 degree angles from the horizontal, all ellipses are 35 degrees.

Key line:
an outline drawing used as the basis for artwork or illustration.

Layout:
a rough or finished design showing the positions of component graphic elements such as type and illustration in correct scale and relation to each other.

Line work:
illustration drawn with black ink line on white art board or drafting film. Also the technique of producing such an image.

Liquid masking:
also called masking fluid, a rubber compound solution which is painted on a surface and dries to a thin rubber skin, then acting as a mask until it is lifted and removed.

Local colour:
the actual colour of an object or surface disregarding effects of light, shade or reflected colour.

Marker:
a drawing tool consisting of a metal or plastic casing containing a fibrous reservoir saturated with coloured ink, which feeds a felt or fibre nib.

Mask:
a material or object used to protect an area of the support while paint or ink is applied, leaving an area uncoloured. This may be paper, board or acetate, an adhesive masking film, liquid masking or even a three dimensional object.

Masking film:
a flexible plastic self-adhesive film used as a mask but also in association with other painting and drawing techniques.

Mechanical tints:
prepared self adhesive sheets of linear or dot patterns which can be applied to artwork or line illustration to create tonal values.

Modelling:
in illustration, the manipulation of colour and tonal values to create and effect of three dimensional form.

Monochrome:
the description of a drawing or painting worked wholly in black, white and grey, or in tones of a single colour.

Objective Drawing:
the practise of drawing from direct observation of an object to produce a detailed and realistic image.

Proportional dividers:
precision instrument for accurately dividing lines or circles into an equal number of divisions.

Ruling pen:
an adjustable drawing pen with a small hand filled reservoir for applying controlled lines of paint or ink.

Rendering:
the process of creating a drawn or painted image. Also the finished image itself.

Rough:
a rapid and loosely worked sketch showing the basic form of an illustration or design.

Scaling up:
the method of enlarging an image by creating a geometric grid over the original and reworking it on a proportionate grid. The same method can be used to scale down (reduce) the image.

Scratching back:
a method of altering a painted or drawn image by removing the medium from the support with the blade of a scalpel or similar tool. This is used in airbrushing to remove colour in order to create highlights and in line work to lift ink where a correction is to be made to the image.

Spattering:
the technique of applying paint or ink as irregular dots of colour. This can be hand-done by flicking colour from  the bristles of a brush, or as an airbrush effect using a special spatter cap or by adjusting the spray quality.

Starburst:
a highlight effect used in airbrushing which resembles a star radiating light.

Stippling:
the technique of applying tone or colour as tiny dots rather than solid shading in either painting or drawing.

Study:
a drawing or painting which forms part of the reference for a finished illustration.

Support:
the material on which an illustration is painted or drawn, e.g. art board, paper, drafting film.

Tone, tonal values:
the range of light and dark elements in a monochrome or colour rendering comparable to a scale of values passing from black through a range of greys to white. Effects of graduations through light and shade are essential to accurate rendering of solid forms.

Tooth:
the grain or surface texture of a support which enables particles of a drawing or painting medium to attach to it. A smooth art board has very little tooth; a rough paper, for example, has pronounced tooth.

Trammelling:
a method of drawing an ellipse by reference to the measurements of its major and minor axes.

Transparency:
the quality of a material which transmits light and can be seen through.

Under painting:
the technique of building up an image by laying in areas of light and shade in monochrome before applying washes or glazes of colour.

Wash:
a thin layer of transparent colour created by a paint medium diluted with water. Laying washes of colour is a characteristic technique of watercolour painting but can also be applied to work in gouache or acrylics.

Watercolour:
paint consisting of pigment in a gum binder which typically provides transparent colour qualities.

Working drawing:
a drawing which forms preparation for a finished illustration or design and is produced as part of the working process rather than as an image in its own right.