Invented from CopiesInvented from Copies

Curator Ellen Smit investigates this reproduction technique's introduction into architectural practice and its popularity between 1955 and 1985.

Architects commended the zip's liberating qualities due to its wide availability and simplicity of application, and its look conveyed the cultural modernisation they were seeking. Although the use of these self-adhesive films declined after 1985, they remained appealing to contemporary architects, such as Frits van Dongen and Michael van Gessel, until the 2000s.

However, zips were not originally conceived and designed for architectural design practice. Sources indicate its first adopters were illustrators and graphic designers, with early appearances of the material in the advertising and graphic design sectors. Adhesive films also frequently appear in all kinds of guises in the archives of architects. Through which media or channels did architects become acquainted with this material? How and why did they use zips in their designs? How is this material visible and recognisable in Het Nieuwe Instituut's archives? And what are the future research questions regarding the introduction and use of zips?

Zips were industrially manufactured self-adhesive plastic films available in colour and black and white. The adhesive layer is paper-thin and translucent and has a removable backing layer. The designation 'zips' originated as a nickname among French architects and derived from the Zip-A-Tone brand, which started marketing self-adhesive plastic sheets in 1937.

Cellulose acetate has been on the market since 1911 and is the main component of zips. Earlier variants of cellulose were developed, patented and marketed in the 19th century for industrial products, advertising, photography and animations. Walt Disney experimented with drawings in combination with celluloid for his first cartoons in the 1920s. Around this time, experiments in the advertising world also influence the development of zips. In 1923, Havy Q.R. Crowder obtained a patent in the United States for a new type of drawing sheet with a suitable adhesive for use in the advertising industry. His invention consisted of a pad of pre-printed sheets of patterns and grids, allowing Illustrators to add ready-made backgrounds to their drawings. This instant product aimed to expedite the work process and replace manual drawing work. Crowder also provided a formula for an adhesive to adhere the various films.

It is unclear whether Crowder considered using cellulose acetate for his sheets, but his idea of working with pre-printed sheets to replace manual hatching and drawing became one of the zip's selling points. Crowder introduced his invention in the 1930s, and in 1937 Zip-a-Tone started selling zips in the United States. This company became one of the major international players and remained in existence until around 2004.

Few sources indicate how zips were introduced to architects in their early years. Handbooks for architects in the 1920s and 1930s make no mention of using zZips for architectural design practice. Architects probably became acquainted with this material through magazines, exhibitions, trade fairs and advertisements, the latter being an initial target market of the material. The progressive architecture magazine De 8 en Opbouw, which was strongly influenced by the new design of the Bauhaus, contains advertisements from the early 1930s that may have used zips, but this cannot be said with certainty. Building contractor Boele Van Eesteren commissioned graphic designer Paul Schuitema to make these advertisements, establishing a new visual language for them that was abstract, clear and business-like, in line with this magazine's progressive outlook.

Contact and collaboration with graphic designers also introduced architects to zips. For example, Schuitema also designed the cover template for De 8 and Opbouw, using halftone overlays and designing what was then a modern sans-serif typeface. Magazine articles also informed architects of each other's office practices. Again in De 8 en Opbouw, we likely see the first modest architectural presentations incorporating zips or pre-printed surfaces, such as for the representation of sunlight entering a building block.

After 1945, zips made inroads into Europe, Australia, South America, and other parts of the world. In Le Corbusier's 1955 publication Modulor 2, he writes about three Zip-A-Tone patterns: one with dots, one with lines, and one with a grid, dots and lines. The interplay of these patterns fascinates him. Superimposing patterns allows for unexpected formal kinetic experiments, which he uses in designs for carpets and facades that emphasise graphic linearity. Playfully arranging and ordering Zip-A-Tone patterns gives Le Corbusier a new creative outlet.

From 1950, British illustrator, urban designer and architecture critic Gordon Cullen began presenting architectural drawings that used zips in magazines such as The Architectural Review and The Architects Journal. He combines zips with hand-drawn illustrations of existing towns and cities, assessing whether the design of urban spaces is 'good' or 'bad'. Visualisations and publications by Le Corbusier and Gordon Cullen were widely distributed in the 1950s. They appear in several languages, establishing zips as an attractive and contemporary design and imaging material for many architects.

Another way architects became acquainted with zips was through the product catalogues of manufacturers and suppliers. Such companies flourished from the late 1960s and experienced significant growth in the 1970s and 80s, with branches worldwide. Major brands included Zip-A-Tone, Letraset, Mecanorma, Normatone, Neschen and Alfac. Their catalogues became increasingly extensive in the 1970s. Their broad target market includes designers, architects, artists, engineers, cartographers, architectural drafting technicians, illustrators, advertisers and all kinds of other creatives - as well as the general public, because the companies' product instructions suggested that anyone could work with adhesive films. The vast product range enhanced the popularity of zips. Over a hundred grids and patterns were available in matte or glossy hues. The product range included hundreds of fonts with variants in many colours. Renowned graphic designers selected the fonts for zips producers during those years.

Brands such as Letter-Press, Letratone (part of Letraset) and Para-Tone targeted the architectural market. They sold heat-resistant self-adhesive plastic films that could go through diazo machines, making them suitable for the light-based reproduction of architectural designs. Thus, transparencies with adhered films remained undamaged during the reproduction processes. Besides heat resistance, making good reproductions requires adhesive films and inks with a high degree of translucency and a good quality adhesive. The range available to architects included self-adhesive films with different thicknesses (like Zip-A-Line), perspective lines, all kinds of objects, furniture, people, animals, trees, plants, aeroplanes, cars, and so on. There was a wide choice of variation and styles, both abstract and figurative. The sizes of the figures and objects corresponded to drawing scales used in architectural practice, such as 1:100 or 1:200.

These companies also sold instruments and accessories, such as blades to cut away the film and sprays to keep transfers from moving while pressing. Most brands sold their products as part of a larger product line. Letraset went one step further and offered instructors who could also set up a studio dedicated to working with Letraset at the architect's office. Letraset also advertised the quality and contemporary appeal of their typefaces. Architects learned about these product catalogues through colleagues' work, advertisements in magazines, sales pitches and manufacturers' promotional material. They could order materials from a sales representative or purchase them at specialist office supplies companies.

In 1980, architect and scientific researcher Fred Stitt published Systems Drafting. The book describes various visualisation and drawing systems for the architect, for which the analogue copying technique was essential. Systems drafting revolved around separating constant information from variable information. Zips were suitable for adding variable information to a design drawing. Source: Fred A. Stitt, Systems Drafting: Creative Reprographics for Architects and Engineers, McGraw-Hill Book Company, 1980. Collection Het Nieuwe Instituut (book number 161.384).

From the early 1970s, architectural handbooks provided guidelines for working with zips. Architects and students learned how to apply zips and which brands were suitable for architectural practice. They listed zips' advantages, such as workflow efficiency, and also - unlike commercial catalogues - their disadvantages. In practice, not everyone could work with zips immediately. Gaining a 'feeling' for the material took practise, and applying larger surface areas (more than 10cm) required precision and a steady hand. Repairing accidents, such as air bubbles, folds, faulty adhesions and accidentally cutting the underlying drawing on tracing paper, wasn't always possible.

Some manuals not only explain the technique but also address the implications of the zips reproduction technique for design practice. They point to the great potential of zips in combination with light-based reproduction technology, including the separation of constant and variable information during design rendering, which makes the design process more efficient. This separation of constant and variable information also implied a new role for architectural drafting technicians, who no longer made elaborate or superfluously decorated design drawings. Instead, they limited themselves to the design's necessary information to be communicated to third parties at a particular stage in the design process.

Instruction manuals and product catalogues contain guidelines for working with zips. They sometimes differ in detail depending on the brand. Usually, the advice is to apply films on the back of the translucent paper because it gets dirty less quickly and adheres better than on the front. Other sources say application on the front side is better because it is easier to make changes afterwards.

Apart from these variations, the manuals generally specify the following guidelines:

• First, cut out a piece of film that is slightly larger than the size you need and remove it from the backing sheet;
• Position this film on the applicable part of the design;
• Cut out the precise shape of the film with a sharp knife;
• Gently remove the excess film;
• Rub down the remaining film for good adhesion of the film to the transparency.

The instructions differ depending on whether applying letters, numbers or the wide variety of symbols. The form is already cut out into the adhesive film so that it can be applied directly to the document. It is essential to choose the right size according to the scale of the design. Scaled-down designs for publication should use letters that are large enough and spaced so as to remain legible. Most manuals and product catalogues provide the following guidelines:

• Draw reference lines or a right angle where the letters/numbers should go;
• Determine the position of the letters/numbers on the sheet, using a reference line and an angle of 90 degrees for a straight position;
• Determine the correct spacing of letters/numbers/symbols;
• Rub over the letter from top to bottom with a ballpoint pen, applying moderate pressure until the letter has adhered to the underlying surface;
• Make sure that other letters do not adhere by accident;
• Difficult surfaces (linen, metal) may require a 'pre-release technique': first rub over the letter with the protective backing layer still in place until the letter turns grey (pre-release), press the letter onto the recipient surface and rub hard until the letter adheres.

The first examples of plastic films in Het Nieuwe Instituut's archives date from 1935 to 1945. Cellulose was a contemporary and experimental material during this period, offering new technical and visual possibilities. Architects Koen Limperg and Johan Niegeman, both progressive designers at the time, kept samples of plastic films in their archives. Though not (yet) self-adhesive, they come in different thicknesses and colours, including green, red, purple and blue. Specific applications of the material for architectural design are not yet evident. Still, these samples of plastic film indicate a knowledge of and perhaps a fascination with this modern material because of its glossiness, translucency and bright colours. For example, Limperg cut the thin films into long garlands with perforated holes and into flowery shapes. This use of the material recalls his imaginative set designs for plays and ballet performances in the 1920s and 1930s. We can also connect them to Limperg's penchant for using contemporary construction techniques and materials in his architectural designs.

Another early indication of self-adhesive plastic film's application in architectural design is in a design drawing by Johan Niegeman from 1939. The design is for the exhibition In Holland staat een huis [In Holland There's a House], at the Stedelijk Museum in Amsterdam, about contemporary interior design. Niegeman oversaw the entire design of the exhibition, and his floorplan has a pencilled annotation to apply a zip with a screentone. It reads 'rectangle is grid No 21' [rechthoek is raster No 21], indicating the robust architectural components such as the construction of a full-scale workers' house and load-bearing walls. His annotation instructs the designer/printer to apply film number 21 from a zips catalogue onto the design drawing for publication. The result is the dotted screentone pattern seen in a drawing in a 1941 edition of D_e 8 en Opbouw_ magazine. Niegeman's fascination with zips is also evident in a sketchbook from one of his students. In the archive of his student Bé Brand, a sketchbook from her student days at the applied arts school the Instituut voor Kunstnijverheidsonderwijs, includes an interior design by a fellow student, depicting a cupboard with transparent film pasted onto it. Perhaps the designer had the sheen of a lacquered cabinet in mind?

The extensive application and integration of zips into architectural design practice mainly happened between 1965 and the 1990s. Many zips appear in Het Nieuwe Instituut's archives during this period. Archives in which zips regularly appear include those of Van den Broek en Bakema, Jan Verhoeven, Gerard Snelder, Gerrit Rietveld, Willem Wissing, Nel Verschuren, OMA, Architecten Cie (Pi de Bruijn, Carel Weeber, Frits van Dongen), Onno Greiner and Michael van Gessel. This broad spectrum demonstrates that zips were useful in many fields, including urban planning, garden and landscape designs, spatial-architectural designs, interior designs, architectural details and architectural components. Zips appear at different stages of the design process and on different types of drawings, such as design drawings, construction drawings, implementation drawings and publication drawings. This broad application means that they are used at all levels of architectural drawing scale, from 1:1000, 1:500 (and so on) up to 1:5 and even 1:1.

Het Nieuwe Instituut's archives indicate that architects and designers applied zips in a free and creative way as a design and visualisation tool, contrary to the strict instructions in product catalogues and manuals. We see adhesive films adhered glossy side up to the front of a drawing and examples where the substrate (the translucent paper) has been cut away. Other variants show double-sided transparencies covered with adhesive films on both sides (a glossy side on both sides), or we see several films stuck on top of one another. Manuals, product catalogues and magazine articles offer various reasons for working with adhesive plastic films, with the three most important considered to be the efficiency of the design process, the reproducibility of the design and expressing a new form of visualisation.

Working with zips replaces often dull and repetitive drawing work, such as manually applying the same patterns for rendering pavements, masonry, floor and wall cladding and shadow areas. Architects used to draw these details by hand using various hatching and feathering techniques, as well as collage: sticking pieces of paper and card onto the design to represent certain aspects quickly in one go. Adhesive films partly replaced these former practices of manual drawing and pasting. Another advantage of zips was that they came ready to use: pre-printed or coloured and self-adhesive. Working with self-adhesive films expedites adding supplementary details to a drawing.

In the past, architects populated their (presentation) drawings with manually drawn figures, furniture, trees, cars and all kinds of other attributes to give their design a contemporary character and a suggestion of liveability and humanity. Catalogues with pre-printed sheets of figures and objects replaced such drawing practices. Over time, architects start pre-printing title blocks for company and project data. The fixed data, such as name and address, were pre-printed on the foil, and variable data, such as approval of the design or the creator's name, could be filled in by hand. Interviews with former employees show that the promise of time and cost savings needs to be put into perspective. Firstly, zips with colours and patterns weren't particularly cheap. Secondly, working with zips only saved time if someone was experienced in working with them efficiently and accurately. So, in practice, zips often didn't improve efficiency without prior investment in knowledge and material.

An important claim for using self-adhesive films was that their translucency made them suitable for diazo reproductions, also known as whiteprints. The method is as follows: an architectural design on tracing paper is covered with a background film representing a pavement or cloudy sky, or emphasising specific parts of the design. The architect then used the diazo technique to make one or more reproductions (diazotypes) from a single transparency. The coloured zips changed to specific shades of grey on the diazotype, ranging from very dark to very light, depending on the hue of the film. Yellow films resulted in a dark grey, and blue films gave a light grey. Architects used these diazotypes for publishing in magazines, providing information to clients, or presentations in exhibitions. They also used diazotypes to further work on a design and share it with other parties who might add their own information.

Architecture handbooks, the application of zips as seen in Het Nieuwe Instituut's archives, and interviews with experienced experts all reveal that zips were appreciated for their contemporary look and design. The material's unprecedented possibilities, broad applicability, immediacy, democratic quality (in theory, anyone could buy and work with them), and many reproduction options lent zips an air of modernity and futurity. Another reason for working with zips was the design drawing's subsequent higher quality, allowing for more nuanced and abstract imagery without the irregularities of handwork.

The look of the material also played a role. Their bright colours and abstract patterns meant many designers considered zips to be a visually appealing design medium. The lustre and translucency enhanced their attractive glossy aesthetic.The fact that leading architects - like Le Corbusier, Gordon Cullen, Archigram, Cedric Price and Peter Eisenman -experimented with this material added to the appeal of the resulting imaginative and futuristic architectural visions. Cullen was one of the first architects in Europe to work with self-adhesive films in his architectural and urban visualisations from 1950 onwards. Using drawings with self-adhesive films, he published his Serial Vision, a method that clarifies, comments on and sometimes 'corrects' the spatial cohesion between different urban environments through successive drawings and visualisations, such as comic strip panels or a film storyboard. According to Cullen, the low threshold of Serial Vision made it an accessible form of visual communication, and his message could reach a larger audience. The Serial Vision technique especially crops up in the archives of Van den Broek en Bakema, such as in the design for the centre of Almere Haven (c 1975).

The follow-up research on zips focuses on their influence on the interaction between architectural concept and visual presentation and on their impact on architects' design methods. The latter also examines how digital design methods can be traced back to analogue design and reproduction practices.

• 'Gordon Cullen en Serial Vision', De Architect, Special Issue Presentation, November 1, 1980, p.38-39.
• M. Cinqualbre, et al., 'Zip: An adhesive plastic film in architectural drawings', Studies in Conservation, 61: sup 2, 283-285, 2016.
• R. Gargiani, A. Rosellini, S. Piccolo, Le Corbusier : béton brut and ineffable space, 1940-1965 : surface materials and psychophysiology of vision, Lausanne Oxford , EFPL Press: Routledge, 2011 (Essays in architecture)
• R.W. Gill, Manual of Rendering with Pen and Ink, London, Thames and Hudson, 1981 (first edition 1973).
• M. Engler, Cut and Paste Urban Landscape, The Work of Gordon Cullen, New York, London, Routledge Taylor & Francis Group, 2016.
• Stitt, F., Systems Drafting Creative Reprographics for Architects and Engineers, New York, St. Louis, London, New Delhi, Tokyo and other places, McGraw-Hill Book Company, 1980.