EP1719099A2

EP1719099A2 - Sheet printed on both sides

Info

Publication number: EP1719099A2
Application number: EP05716691A
Authority: EP
Inventors: Caren Kock; Udo Leichauer
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2004-02-13
Filing date: 2005-02-14
Publication date: 2006-11-08
Anticipated expiration: 2025-02-14
Also published as: WO2005078688A3; EP1564707A1; WO2005078688A2; EP1719099B1

Abstract

Sheets, in particular bill posters, which are printed on both sides and have at least one of the items depicted on the front in mirrored, but incomplete form on the back, process for their production and display cases comprising such sheets.

Description

Sheet printed on both sides

The invention relates to sheets (flat-shaped articles) printed on both sides, in particular bill posters, a process for the production of such sheets, and display cases 5 comprising such sheets. It is known to print bill posters on both sides using the four primary colours (cyan, magenta, yellow and black) on the front and three colours except black on the back. These posters create a colour impression even when the bill poster0 is illuminated from behind, for example in illuminated display cases in the dark. Bill posters for such use exhibit on the back the identical motif as on the front, but in mirrored form. Both sides of the bill poster are printed using the same printing process, for example offset printing.s Furthermore, it is known to print the back of bill posters with the same motif as on the front, but using a different process on each side, for example offset printing on the front side and silk screen printing on the back side. Such practice may offer a cost advantage.o Conventional bill posters printed on both sides have several disadvantages. For example, on illumination from behind the colour intensity is not as good as during daylight. In addition, it is impossible to adapt the impression created by the bill posters to the special5 requirements of reduced light conditions. For example, details of the motif cannot be emphasized in order to enable good recognition under reduced light conditions . Likewise it is impossible to achieve different appearances under normal and reduced light conditions, but in combination witho illumination from behind. It is an object of the present invention to overcome the disadvantages of the state of the art including those described above and, in particular, to provide improved bill posters printed on both sides. The present invention provides a sheet having a first and a second side, wherein the first side depicts one or more 5 items in colour print, formed from the primary colours cyan (C) , magenta (M) and yellow (Y) , optionally supplemented by black (K) , and wherein at least one of the items depicted on the first side is represented on the second side in mirrored but incomplete form; or wherein at least one of the items0 depicted on the first side is depicted on the second side substantially lacking at least one of the colours of the group consisting of cyan, magenta and yellow (as compared to the corresponding item on the first side) . In particular, the present invention provides a sheets printed on both sides, in particular a bill poster, with a front side facing the observer and a back side facing away from the observer, the front depicting one or more items printed in colour, formed from the primary (basic) colours cyan (C) , magenta ( ) and yellow (Y) , optionally supplementedo by black (K) , at least one of the said items on the front being reproduced on the back in mirrored but incomplete form, optionally additionally in complete colour. As used herein, a depicted item may be any individual element or motif contributing to the overall image, such as,5 for example, a person, an animal, a background element, a written character or a logo. Advantageously, the incomplete reproduction of an item depicted on the back is achieved because the colour of said item is selected such as to be substantially identical to theo colour in the area immediately surrounding this item. Therefore, within the scope of colour identity between the item and the surrounding area, the contour of the depicted item is no longer recognizable when looking at the back. If desired, the contour may be added again, by the addition of, for example, black boundary lines. The colour identity is preferably formed by a red shade, preferably covering at least about 50%, more preferably at least about 75%, most preferably at least about 90% of the back side of the sheet. 5 Preferably, with the exception of black, the colours of most, nearly all or all items depicted on the front, are substantially replaced with one uniform, preferably red, colour shade for reproduction of the corresponding items on the back.o As a result of being illuminated from behind, the incomplete, optionally colour-reduced items depicted on the back are overlaid with the corresponding complete (as to form) , full-colour items depicted on the front, resulting in a uniform overall image for the observer. Details of thiss overall image may be strongly emphasized in comparison to what is observed during daylight, in particular those details of corresponding items depicted on the back which are represented by dark colours, in particular in black. In other words, front and back sides show different overall images aso the depicted item or items of the front are seen only partly on the back, albeit in the same position or positions. Therefore when looking at the back the observer does not automatically recognize the item or items depicted of the front. However, the observer surprisingly becomes aware of as complete image of the items depicted on the front when the sheet is illuminated from behind, even though, contrary to the state of the art, the items on the back are depicted only in part. Individual depicted items which may be applied in complete form to the front of the sheets according to theo invention include, without limitation, motifs such as animals, people and vehicles, background elements such as landscapes or skyscapes, written characters such as slogans, trademarks or logos such as company or product logos . At least parts of the items depicted on the front are also found on the back, but in each case the item on the back is derived from the mirror image of the corresponding item depicted on the front . Advantageously, black is used for the representation of 5 incomplete items depicted on the back. If desired, one or two additional colours selected from the group consisting of yellow, blue and red may be used. The preferred black colour supports the emphasis of individual details as the overall image merges on illumination from behind. The additional use0 of, for example, yellow for other details of the incomplete items depicted on the back, has the effect that, upon merging, the items depicted on the front which are preferably yellow in the same positions, are more strongly emphasized on illumination from behind.s Furthermore, it is advantageous to use different types of colour for the items completely depicted on the front and the one or more items partially or incompletely depicted on the back. In particular, it is advantageous to print the front with customary (translucent) screen inks (or screeno colours) in colour print and supplementing an extensive area on the back with one or more customary line inks (line colours) . Such use of line inks has the surprising effect that the overall image resulting from the merging of the front and back sides on illumination from behind creates an5 impression which is very different from the impression created by overall image formed on observation of the front during daylight. In this case it is particularly advantageous if the transparency (translucence) of the line inks on the sheet is significantly lower than the transparency of theo screen inks on the sheet. For example, as compared to screen ink transparency, the transparency of the line inks may be more than about 50% lower, preferably more than about 100% lower, in particular more than about 500% lower, most preferably more than about 700% lower, as measured in the corresponding positions of the front and the back. By way of example, and preferably, a colour which has not been used extensively on the front, such as a deep red, may be applied as a line colour on the back, whereby the items depicted on 5 the front are immersed in a different atmosphere when illuminated from behind. It is also conceivable to use as line inks other colour shades, such as warning shades, which may be used to convey warnings to the observer on illumination from behind. If shades used on the front are0 used as line inks on the back, the result for the overall image is a general emphasis on the items depicted on the front on illumination from behind. It may also be advantageous to print the front and back of the sheets using different printing processes ors techniques. For example, the front may be printed using offset printing while silk-screen printing is used for the back. The combination of different printing processes may further enhance the effects described above. In particular, silk-screen printing allows the line inks to be applied cost-o effectively, over a large area or extensively and with high colour density. In a preferred aspect of the present invention, the colour density of the items depicted on the back is higher than the colour density of the items depicted on the front,5 preferably between about 5 and about 10 times higher, more preferably between 6 and 8 times higher. The higher colour density on the back again enhances the effects described above, and, on illumination from behind, the colour shades of the line colours are powerfully transported to the front buto surprisingly without rendering the items depicted on the front unrecognizable by being overlaid. Preferably, the colour density of the items depicted on the back is between about 5 and about 50 g/m², preferably between about 20 and about 40 g/m², particularly preferably about 30 g/m². Preferably, the colour density of the items depicted on the front is between about 1 and about 5 g/m², preferably between about 2 and about 4 g/m², particularly preferably between about 3 to about 4 g/m². 5 The processes and techniques suitable for printing the sheets according to the invention are known in the art, for example, planographic (flatbed) printing, for example offset printing or lithographic printing, as well as screen printing processes, for example silk-screen printing - see, foro example, Rδmpp-Lexikon Lacke und Druckfarben [Rδmpp Encyclopaedia of Varnishes and Printing Inks], 10^th edition, Thieme-Verlag 1998, heading "Druckverfahren" [Printing Processes] including the references cited therein. Further suitable printing processes include, among others, thes following: relief printing processes, for example letterpress printing or flexographic printing, gravure or rotogravure (intaglio) printing processes, for example blade rotogravure printing or steel engraving printing, or line gravure printing.o As mentioned above, the back sides of the sheets according to the invention show at least one of the items depicted of the front, but incompletely. However, the back may also depict items which are lacking from the front. In such case, on illumination from behind, the items depicted on5 the back are combined with those on the front creating a uniform overall image for the observer. Therefore, what the observer recognizes on the bill poster under normal light conditions, for example, during day light, is different from what he sees when it is dark and the bill poster iso illuminated from behind. The darker it is, the more powerful the effect of the rear-printed colours . In another embodiment of the present invention, specific parts of the items depicted on the front may not be repeated on the back, which means that such parts represent unprinted points or areas on the back. On illumination from behind, the essentially unattenuated light is transported to the corresponding point or area on the front, thus creating a very strongly emphasized, bright and radiant point or area in the overall image. Such effects are particularly suitable for the representation of individual motifs such as stars, light sources, burning cigarettes or written characters. In yet another aspect, the present invention also provides a display case which comprises at least one sheet according to the invention, preferably a bill poster, as well as at least one light source for lighting same from behind. Preferably, a display case according to the invention may be any type of device which enables the housing of at least one bill poster with the aim of said bill poster being noticed by potential consumers together with at least one light source. Advantageously, the housing is such that it substantially protects the bill poster against any adverse environmental influences. Examples of display cases according to the invention are glass display cases as used at stops of public transportation means. The present invention also provides a process for the production of sheets printed on both sides, preferably bill posters. One or more items are depicted on the front in colour printing, formed from the primary colours cyan (C) , magenta (M) and yellow (Y) , preferably supplemented by black (K) . At least one of the items depicted on the front is applied to the back in mirrored, but incomplete form, or in incomplete form and incomplete colours (C, M, Y, K) . As used herein, sheets are media which may be colour printed on both sides, the front and the back, in particular bill posters, coupons, menus or other advertising materials. The sheets of the invention may be made from any suitable material, or combination of materials, including, for example, paper, film materials such as polyethylene or polypropylene, foil materials, coated or uncoated glass, thermoplastic materials, such as rigid PVC, polystyrene or polycarbonate, or a ceramic material. Preferred media within the framework of this invention are cloud- and streak-free double-matt coated bill poster papers measuring from about 50 to about 120 cm times from about 70 to about 180 cm and having a basis weight of between about 100 and about 200 g/m², preferably between about 135 and about 170 g/m², most preferably between about 135 and about 150 g/m². The bill posters may be erected flat as such or undergo post treatment steps such as folding or glueing. For example, if desired, a three-dimensional hollow structure with 3 to 8 sides may be created by folding and, optionally gluing, with at least one light source being placeable inside said structure. Likewise, two opposite edges of the bill poster may be joined together to obtain a hollow cylinder. In its middle at least one light source is placed which illuminates the bill poster from behind when there is less light . It is also envisioned that at least one item on the front is reproduced on the back in complete form (based on its contour) using at least one of the colours C, M, Y and K, but in such case the back side is kept in a uniform colour, preferably covering an extensive area, preferably at least about 50% and in particular at least about 75% of the total surface of the back. This uniform colour is preferably a red shade, preferably a line ink within the above-mentioned ranges for colour density and transmission, respectively. The invention is further illustrated by way of the following examples, without being limited to them. Example 1 A bill poster measuring 117.5 cm x 178 cm made of cloud- and streak-free double-matt coated bill poster paper with a basis weight of 150 g/m² is printed in colour on the front with a cowboy motif plus the background, written characters and a logo using a customary offset printing process. On the back, parts of a mirrored cowboy representation of the front are printed using a customary silk-screen printing process. Only individual areas of the cowboy motif are applied in black. All other areas of the cowboy representation on the back and all other items depicted on the front - with the exception of the written characters - are printed with strong red and yellow line inks . The average colour density of the overall representation on the back is about 7 times higher than the colour density of the overall representation on the front . In daylight the observer is aware of the cowboy motif represented in colour. When illuminated from behind in a display case, the impression changes, however, such that the cowboy motif is recognized, but in a schematic representation, immersed in an extensive, deep-red impression suited to night light, which enables an excellent recognition of the cowboy motif through the emphasis on the black colour of the back. Example 2 By way of variation from Example 1, a full moon is additionally depicted on the back of the bill poster in such a way that a circular area of the back is essentially not coloured in. When the bill poster is illuminated from behind the impression changes (as compared to daylight without illumination from behind) and the observer becomes aware of the overall (composite) image comprising the items depicted on the front, that is the cowboy, the corresponding backgrounds and the written characters, plus the full moon. Therefore what is depicted and recognized during daylight differs from what is recognized at night when it is lit from behind. What is actually observed in this example by day is the overall image giving the impression of day, while at night the same overall image is recognized, lit from behind but giving the impression of night, with a red hue.

Claims

Claims 1. A sheet having a first and a second side, wherein the first side depicts one or more items in colour print, formed from the primary colours cyan (C) , magenta (M) and

5 yellow (Y) , optionally supplemented by black (K) , and wherein at least one of the items depicted on the first side is represented on the second side in mirrored but incomplete form; or wherein at least one of the items depicted on the first side is depicted on the second sideo lacking at least one of the colours of the group consisting of cyan, magenta and yellow (as compared to the corresponding item on the first side) .

2. Sheet printed on both sides according to claim 1, ins particular a bill poster, wherein the first side is the front facing the observer and the second side is the back facing away from the observer, the front having one or more depicted items in colour printing, formed from the primary colours cyan (C) , magenta (M) and yellow (Y) ,0 possibly supplemented by black (K) , characterized in that on the back at least one of the depicted items of the front is reproduced in mirrored but incomplete form.

3. Sheet printed on both sides according to claims 1 or 2,5 characterized in that on the back at least one of the depicted items of the front is reproduced in mirrored but incomplete form and incomplete colours (C, M, Y, K) .

4. Sheet according to claims 2 or 3, characterized in thato the partial reproduction of the at least one item depicted on the front is in black, possibly supplemented by one or two further colours .

5. Sheet according to any of claims 1 to 4, characterized in that it is printed on the front using an offset printing process and on the back using a silk-screen printing process .

Sheet according to any of claims 1 to 5, characterized in that the colour density of the depicted items on the back is higher, preferably between 5 and 10 times higher, than the colour density of the depicted items on the front.0

7. Sheet according to any of claims 1 to 6, characterized in that, on observation of the front with and without illumination from behind, in spite of reduced-colour printing of the back, one and the same overall images results, possibly with the exception of unprinted points or areas on the back.

8. Sheet according to any of claims 1 to 7, characterized in that at least one colour of at least one item depicted on0 the front, preferably of several immediately adjacent items depicted on the front, is replaced with a single colour in the corresponding positions on the back, preferably a red shade. 5

9. A three-dimensional structure comprising at least one sheet according to any of claims 1 to 8, 12 or 13.

10. Display case comprising at least one sheet, preferably a bill poster, according to one of claims 1 to 8, 12 or 13,o or a three-dimensional structure according to claim 9 and at least one light source.

11. Process for the production of a sheet printed on both sides, preferably a bill poster, one or more colour- printed depicted items being applied to the front, formed from the primary colours cyan (C) , magenta (M) and yellow (Y) , possibly supplemented by black, characterized in that at least one of the items depicted on the front is applied to the back in mirrored but incomplete form, optionally also in incomplete colours (C, , Y, K) .

12. Sheet printed on both sides, in particular a poster bill, with a front facing the observer and a back facing away from the observer, the front having one or more depicted items in colour printing, formed from the primary colours cyan (C) , magenta (M) and yellow (Y) , possibly supplemented by black (K) , characterized in that on the back at least one of the depicted items of the front is reproduced in mirrored but incomplete form or incomplete form and colours (C, M, Y, K) .

13. Sheet printed on both sides with a front facing the observer and a back facing away from the observer, the front having one or more depicted items in colour printing, formed from the primary colours cyan (C) , magenta (M) and yellow (Y) , possibly supplemented by black (K) , characterized in that on the back at least one of the depicted items of the front is reproduced in mirrored but complete form and incomplete colours (C, M, Y, K) .