John Benjamins Publishing Company

This is a contribution fromInformation Design Journal 18:2 © 2010. John Benjamins Publishing Company This electronic file may not be altered in any way. The author(s) of this article is/are permitted to use this PDF file to generate printed copies to be used by way of offprints, for their personal use only. Permission is granted by the publishers to post this file on a closed server which is accessible to members (students and staff) only of the author’s/s’ institute, it is not permitted to post this PDF on the open internet. For any other use of this material prior written permission should be obtained from the publishers or through the Copyright Clearance Center (for USA: www.copyright.com). Please contact [email protected] or consult our website: www.benjamins.com Tables of Contents, abstracts and guidelines are available at www.benjamins.com Information Design Journal 18(2), 94–106 © 2010 John Benjamins Publishing Company doi: 10.1075/idj.18.2.01ada

Austin Adams, Theo Boersema & Meijer Mijksenaar Warning symbology: Difficult concepts may be successfully depicted with two-part signs

Keywords: icons, warnings, pictograms, symbol signs According to ISO/TC145 (the International Organiza- tion for Standardization’s Graphical Symbols committee) Symbol signs – signs without words – are often used to a safety sign involves a symbol of specified color placed communicate safety or public information messages. on a background of specified color and shape. The ISO The International Organization for Standardization (ISO) 3864-1 standard presents design principles for the overall provides standards ISO 3864-1 and ISO 3864-3 giving design safety sign while ISO 3864-3 presents design principles principles for both graphical symbols and completed for graphical symbols used within safety signs. The rules signs in the safety arena. The present study shows that for governing the symbol design refer in particular to the difficult signage circumstances a two-part sign, showing human figure, to arrows and to principles devised to the desired and undesired circumstances with a tick and a ensure adequate visibility. ISO 7010 provides a list of cross, can be much more effective than the normal single- all the currently approved safety signs. Examples of the part sign provided for by these ISO standards. The present five types of safety sign provided for in this standard are study also suggests that ISO’s sign assessment methods shown in Figure 1. could be efficiently combined and simplified. For public information signs there is more latitude. ISO 7001 gives details of currently approved symbols, Designing symbols and symbol signs but the specifications that are given apply only to the symbol as it is possible to create a sign by reproduc- The process of designing a symbol to be used in an infor- ing the symbol in any color and on any background as mation or safety sign involves a complex and poorly- long as the specific combinations of safety colors and understood mixture of art and science beginning with shapes of ISO 3864-1 are avoided and legibility is main- the creative act of generating the essential symbol. From tained. ISO 7001 gives information on how to use text then on, if one intends to submit the information symbol and arrows and how to indicate negation, both where or the safety sign for inclusion in either International the entire symbol is to be negated, as well as where the Standard ISO 7001 or ISO 7010 there is a host of require- negation applies only to a part of the symbol. ISO 22727 ments governing the details of the symbol’s design and, gives more detailed guidelines for the design of public particularly for safety signs, of its presentation in a information symbols covering matters such as the size completed sign. of elements within a symbol and the use of filled areas

94 Austin Adams, Theo Boersema & Meijer Mijksenaar • Warning symbology idj 18(2), 2010, 94-106

the unlikely event that many alternative symbols for the one referent (the concept that the symbol represents) are available, in which case those participating in what is called the Judgement Test are asked to estimate the percentage of the population likely to understand the symbol. This test could be seen as providing a prelimi- Safe condition – Fire safety – Mandatory square, white symbol square, white action – circle, nary weeding-out process. on green ground symbol on red white symbol on The main method is the Comprehension Test, which ground blue ground involves presenting the symbol to respondents with appropriate contextual information, and asking them to indicate what they think it means. To clarify their response they may also be asked to indicate what they would do if faced with the symbol. The standard indicates how to categorize the scores, but the precise criteria for acceptance—stricter for safety signs than for public Prohibition – Warning – triangle information symbols—are not given in the standard but circle, black symbol (apex up), black separately on the relevant ISO/TC145 committee’s web on white ground with symbol on yellow site. If the symbol or sign does not meet the required red annulus and slash ground with black criteria, or indeed if testing is not carried out at all, the border symbol or sign may be accepted into the standard, but Figure 1. Examples of the only types of safety signs must be used with supplementary verbal clarification or recommended by ISO 3864-1, the definitive ISO/TC145 with an appropriate education campaign. standard referring to safety signage. ISO 9186-1 provides what is essentially a pass-fail test. A second standard, ISO 9186-2, asks respondents to indi- in preference to outlines. It also presents a suggested cate in a formal and controlled way what it is that they template for the design of the human figure, gives rules see in the detailed elements that make up the symbol. It for the representation of water and ends with a useful is described as a method for testing the perceptual qual- checklist for designers. ity of the symbol. If respondents can see, say, a man with a walking stick then they can use those words to describe what they see. Otherwise they are asked to describe what Testing they see in terms of the shapes, such as, “a man and next The aim in producing a symbol sign is always that it to him a vertical line with a curved top”. The standard should be comprehended without associated words and prescribes the use of various presentation sizes: a larger without specific education. To assess comprehension, size, with all details easily distinguishable, and one or and hence to determine if supplementary wording or more smaller sizes, together simulating viewing condi- education is required, ISO provides two standards. ISO tions in actual use. The results for the smaller sizes show 9186-1 provides two methods for testing the extent to the symbol’s readability when it subtends a limited visual which symbol signs are understood. The first applies in angle. This test with the larger presentation size identifies

© 2010. John Benjamins Publishing Company 95 All rights reserved Austin Adams, Theo Boersema & Meijer Mijksenaar • Warning symbology idj 18(2), 2010, 94-106 misinterpreted elements within the symbol, thus giving symbol and were asked if, in the light of this information, more precise information that can assist the redesign of a they wished to change or add to their element descrip- poorly-performing symbol than is given by ISO 9186-1. tions. They were finally asked what they thought the symbol meant and what they would do if they saw it. The present project Results supported the contention that giving the context made little difference to the results of the naming task. The present project aimed to use the essence of ISO After being given the context respondents did some- 9186-1’s Comprehension Test combined with the ISO times give a more accurate name to an element within a 9186-2 procedure (using the larger size only) to test and symbol, but this was usually a refinement rather than a then redesign some water safety signs that appeared to material change. We therefore felt confident in proceed- be poorly designed, and finally to test the original and ing with a combination test method in which respon- redesigned signs according to the regime prescribed in dents would be asked to give details of symbol elements ISO 9186-1. The question was whether the methodology (as in ISO 9186-2) and then asked to give the meaning of ISO 9186-2 would be genuinely useful, as intended, in and to indicate what they would do (as in the Compre- providing a designer with information to assist redesign. hension Test of ISO 9186-1).

Preliminary study Experiment 1

A preliminary study was designed to assess the graphic The first study was designed to assess the comprehen- symbol test method of ISO 9186-2, which requires respon- sion of a series of symbols using the new, modified test dents to name the elements they see within the symbol method. This method allows the gathering of informa- without being told anything about the symbol’s context tion about the way respondents perceive the symbol’s so that an unbiased measure of what they see can be elements when an incorrect meaning interpretation is obtained. However, not indicating context makes it diffi- given. The aim was to use element descriptions accom- cult to use the ISO 9186-1 procedure to assess the meaning panying incorrect interpretations as material to assist in of a series of signs that appear in the same context since redesign. It was explained to respondents that descrip- the ISO 9186-1 procedure requires the context to be given. tions of the elements within a sign can be abstract (e.g. If giving the context would not affect the results in any “square” or “circle”), but that it is also permissible to material manner it would allow a more efficient data-gath- interpret an element as an object (e.g. “suitcase” or “car”). ering method for use with a series of symbols. There were six symbols from an initial series Twelve symbols containing elements that were not proposed to ISO as warnings for use on floating leisure immediately obvious were chosen from a variety of articles to ensure their safe use. The source was an initial domains, such as travel, public information, hospitals, draft of CEN prEN 15694-2:2007, since updated. pharmaceutical labeling and water safety. Respondents, As the originally proposed signs were available who were 33 students from Delft University, were not only in a rudimentary black-and-white form, they were given the context but were asked to name the elements. redrawn for the present purposes using the appropriate They were then asked to guess where they might see the ISO colors and shapes. The signs used are illustrated in symbol. Next, they were told where they might see the Figure 2.

consuming and costly is unlikely to be used. A close examination of the data from the preliminary study indicated that sufficient useful redesign information could be derived from the statements about the symbol elements with many fewer respondents than were used in that study. It was therefore decided to restrict the number 1 – Do not use in 2 – Do not use in 3 – Stay within 50m of respondents to 12. Due to financial restrictions, the offshore wind offshore currents of the shore respondents used were volunteers from the secretarial staff and visitors who happened to be in the headquarters of an Australian surf lifesaving organization.

Results

For each sign the responses of two or three respondents giving incorrect interpretations are given. They were 4 – Do not jump if 5 – Ensure that the 6 – Ensure that the selected to illustrate the misinterpretations and are water is not clear device is not too device is not too slightly abbreviated by removing redundant or irrelevant tight loose comments in order to conserve space. When correct and Figure 2. The six signs used in Experiment 1. incorrect response figures are given they have resulted from scoring based on the meaning and the related action statement as indicated in ISO 9186-1. The small Procedure number of respondents and their possibly unrepresenta- tive nature suggests that the absolute percentage correct Respondents were given an A5 booklet beginning with figures should not be relied upon. This investigation was some examples to indicate what is meant by a description primarily to obtain the element descriptions associated of the elements of the symbol. Following this, each sign with incorrect responses. was shown, together with a statement of its context, and then three questions were asked. The first was: “What are Sign 1: Do not use in offshore wind the elements in this symbol? (Please write what is shown, Elements not what you think it means)”. The second was: “What do – Figure in water vessel, striped bucket on pole in water. you think the symbol means?” and the third was: “What – A rock face/cliff to the right with a rounded flag on is this symbol telling you to do, or not to do?” Several top of the cliff. In the water sits a person in a floating blank lines were provided for each answer. vessel, e.g. a canoe. – A wind vane, coastline, rough seas and a person in a Respondents boat. One of the requirements of a testing regime for use in Meanings the testing and redesign of symbol signs is that it should – Do not tow anything behind your vessel. be efficient (Adams, 1999) – a regime that is too time- – Beware of cliff, rock face.

– Dangerous conditions or poor safety at sea. Of the 12 responses, 8 were correct, 3 were wrong with 1 Don’t know/No response. Although 8 of the 12 chose Actions a safe response such as “don’t go boating in this area,” – Do not tow anything behind your vessel. the depiction of the current was clearly a problem for – Turn around, do not head towards cliff. some—the arrow was difficult to interpret and to some – Do not enter the water. looked like a jelly fish. Of the 12 responses, 5 were correct and 7 were wrong. Safe responses, scored as correct, were given by 5 of the Sign 3: Stay within 50m of the shore 12 respondents since they said something like: “Do not Elements use in strong wind,” but only one of those correctly iden- – There is a bank where the water meets land. There is tified the prohibition as being against using the device a buoy with an ! mark in the water with a legend that when the wind was specifically offshore, as opposed to says it’s 50m offshore. Also a rope with floating buoys in any kind of wind. The element descriptions indicated stretching between the shore and the ! buoy. that respondents had trouble with the windsock element – There is a man floating in an object on rippled lines. as 3 of the 12 thought it was a bucket or a flag. On top of the rippled lines there appears to be a rope connected with rectangular shapes and a flag on a Sign 2: Do not use in offshore currents stand. There are also 2 arrows across the top with 50m Elements between them. – There is a tree on land. On the other side of the tree is – Person in water vessel. Flag with advice shallow water. water. Under the boat is a sideways triangle with long Meanings wavy lines trailing from it (maybe a jelly fish). – That boating activities are not permitted within 50m – A tree at the top of a cliff, to the right of the cliff is of the shore. water. In the water is a person sitting in a boat or – Do not use the tube within 50m of a flagged area. canoe. There is also an arrow pointing away from the – Do not moor water vessel there. cliff. – A person on a floatation device on wavy water near Actions land with a pine tree on the land with an arrow under – Move further offshore. the floatation device pointing away from the land. – If you are in a flagged area, move. – Dangerous area, do not moor. Meanings – There are jellyfish in the water. None of the 12 responses were correct: 10 were wrong – Turn around, beware of cliff, rock face. and 2 were Don’t know/No response answers. Five of – There is danger near the land and do not go near it. the 10 wrong responses were in some sense opposite to that intended. There was a clear difficulty in identifying Actions what was being negated. In addition, the element that – Don’t swim in the water. appeared to be a string of buoys in the water was difficult – Turn around, do not head towards cliff. to interpret. – Keep away from the land and the tree.

Sign 4: Do not jump if water is not clear to do with tubes/donuts, but am unsure exactly what. Elements – When lifting tube have hands pointing upwards. – A person swimming, an oval shaped object floating – Not sure? on water and a person on the floating object pointing Actions an arrow at the swimmer. – When lifting tube have hands pointing upwards. – Series of dotted straight lines, one wavy line, torso – Telling you that there are people holding cylinders. of a person partially obscured with one arm raised, straight line with an arrowhead at end, stick person Of the 12 responses, none were correct, 4 were wrong standing on an object with knees bent and arms and 8 were Don’t know/No response answers. There was extended, dark shaped object. great difficulty in interpreting any of the elements of this symbol. Meanings – Do not throw spears from your boat (?) Sign 6: Ensure that the device is not too loose – Do not leave the float aid and swim away. Elements – No spearfishing when people are in the water. – A black tube with what appears to be a person inside Actions it. The person appears to have a rope/chain connect- – Don’t throw spears as there may be swimmers ing their neck with the tube. around. – A solid donut shape. Inside the donut shape is a – Stay with your float aid. human figure bent at the hips. – Be careful if spearfishing. – A person is in a donut (tube) that has a rope attached – possibly for towing. Of the 12 responses, 2 were correct, 9 were wrong, and 1 was a Don’t know response. It appeared that the line- Meanings with-arrow element was a major cause of misinterpreta- – Ensure the chain/rope is connected at all times when tions as it could be interpreted as an arrow or a spear. In in the tube. general, it was not clear what was being negated. – You could get stuck in a donut. Actions Sign 5: Ensure that the device is not too tight – Ensure the chain/rope is connected at all times when Elements in the tube. – A person with outstretched arms, and underneath – Don’t sit in a donut. each arm is a circle. The circles could be part of a tube or pipe as there is white shading connecting the two Of the 12 responses, 2 were correct, 8 were wrong and circles. Also, there appear to be two upward pointing 2 were Don’t know/No response answers. Two of the 8 hands on either side of the person. wrong responses were in some sense opposite to that – A person with arms out to side holding 2 round intended. The dotted line which the designer had possi- circles which look like cylinders. bly intended simply to indicate the shape of the body on the other side of the inflated tube was interpreted by two Meanings respondents as indicating an attached rope. – I think the symbol is some sort of safety requirement

Experiment 2 idea came to mind of making the water grey to indicate pollution or low visibility, but with a dangerous object Symbol redesign included. A branch indicated something generically dangerous, but it had to look like a branch and nothing The next step was to redesign the symbols using the else – one option looked like a shark. Should the information from Experiment 1. Our first approach to branch be at the top, middle or bottom? Should it be the symbolization was to generate an idea that enabled black or white on the grey background? All these were the whole story to be told, with careful refinement of considered, the final choice being the one that, in our detail. Then came the realization that there wouldn’t be informal testing, gave the most consistent responses. We room for all the detail without too much complexity, found that quite small design decisions often made a big so it was necessary to stand back and remove whatever difference in the number of wrong interpretations. Some seemed superfluous to the main story, and whatever was of the design alternatives that were considered are shown mere decoration. in Figure 3. But what can be left out, what is superfluous, and In addition to the two-part signs, and in an effort on further thought, what indeed is the story? Consider to comply with the ISO guidelines, we produced some Sign 3. Testing data showed that the main error was in examples of what we considered to be some clearer one- thinking that the 50m was a minimum indication. Ideas part symbols complying with the ISO safety-sign guide- played on that theme, with nothing working out. lines. We also experimented with alternative symbols in We soon realized that it was going to be difficult to which the negation element applied only to the relevant produce symbols with a high comprehension rate for all aspect of the symbol, taking a lead from the public infor- the signs using the present ISO guidelines as some of the mation symbol guidelines of ISO 22727. messages were too complex to be successfully conveyed At the end of a long road, with much mulling over by a standard sign. A standard sign depicts a single static the misperceived elements and incorrect interpretations situation which, if complex, may lend itself to several of the earlier testing, we decided to test both the interpretations. original versions and, for four of the six signs, two new One possible solution is to indicate both the desired alternatives, making three series of signs for formal and the undesired circumstances within a single sign so testing as shown in Figure 4. that the user is presented with a contrast from which the intended interpretation emerges. With two parts to the Procedure sign, one part with a green tick indicating what to do, or the desired circumstance, and a second part with a red To obtain the 50 independent respondents for each of X indicating what not to do, or the undesired circum- our three series of symbols recommended by the ISO stance, it is possible for the intended interpretation to testing guidelines we were faced with online testing as emerge. Once this two-part idea took hold, possibilities the only option. We were relieved to hear that a proposal opened up. to modify the ISO 9186-1 testing standard to include the Consider Sign 4. A two-part sign made it possible possibility of internet testing was under discussion. After to warn against entering the water unless it was clear by our online testing was completed we received news of contrasting clear with murky or dangerous water. The testing on a series of public information symbols for the

Figure 3. Some of the design alternatives considered for Sign 4. handicapped that used paper-and-pencil methods in the Respondents UK and identical but online testing in Australia. These two testing regimes produced almost identical results (J. The questionnaires were completed by a total of 156 Foster, personal communication, January 28, 2008). With respondents, 78 from Australia, 61 from The Netherlands reasonable controls, such as beginning the questionnaire and 17 others. Their ages and the number responding to with an explanation asking people to work by themselves each series are shown in Table 1. and not to consult over their responses, the differences Table 1. The age distribution of the Experiment 2 between paper-and-pencil and online testing appear to respondents be adequately controlled. Age Series The testing involved three different survey questionnaires modeled on the earlier paper-and-pencil booklets, 1 2 3 but presented on the internet using a commercial survey 15-30 18 24 21 31-50 16 18 15 platform (www.surveyconsole.com). For each symbol the Over 50 15 13 13 two questions were “What do you think it means?” and Not stated 2 0 1 then “What would you do, or not do, if you saw it?” Total 51 55 50

Figure 4. The signs and the related data from Experiment 2 * Includes No response

Results and discussion Sign 2: Do not use in offshore currents The main change in the new signs is in the strengthen- ISO 9186-1 provides detailed instructions for scoring of the water-surface lines and in the way the under- ing using five categories: Correct, Wrong, Wrong and water-current is shown. From something that could be opposite to the intended meaning, Don’t know and No construed as an object such as a jelly fish, as reported by response. The Wrong category includes all incorrect some respondents, the lines depicting current have been responses. The Wrong-and-opposite category separates changed to a more neutral and abstract form following out from within the wrong responses those that are the lines of the surface water. particularly critical for safety-related signs in that the The two new signs performed similarly and some- respondent has interpreted the sign in some sense oppo- what better than the original Series 1 sign. Given that the site to that intended. Series 3 sign is in keeping with ISO 3864-1 whereas the When scoring responses to signs there are often Series 2 one is not, the Series 3 sign is preferred. From difficult decisions. For example, how should “Do not use a statistical point of view the result is marginal (p = .06 the vessel in high winds” be scored as a response to Sign on a one-tailed Fisher’s exact test). None of the signs 1 (Do not use in offshore wind)? We adopted the strategy performs well enough according to the relevant ISO/ of scoring as correct any response that we considered TC145 criteria to be used alone. to be a safe response in the circumstances as long as it That the results from the two new symbols are so did not totally miss the point. “No boating,” for example, similar makes it clear that the attempt to place the nega- would have been scored wrong. tion over the person in the floating device has not added When performing statistical analyses our concern was any information not already conveyed through a simple whether one or other of the new versions performed better negative. The situation shown is a person in a floating than the original. We were also, incidentally, concerned device where there is a strong offshore current. Negat- with the question of whether any of the symbols would ing the person in the floating device says “This person pass the criteria of acceptability required by ISO/TC145 should not be here”. Negating the whole scene says “This for safety signs to be used without supplementary text, situation should not occur”. Both messages have the same which is at least 86% correct with a percentage of opposite behavioral consequence. responses that does not exceed 5%. Details of response category percentages are given in Figure 4. Sign 3: Stay within 50m of the shore As with Sign 2, the two new signs performed similarly well, Sign 1: Do not use in offshore wind but in this case a one-tailed Fisher’s exact test indicates All three versions tested in Experiment 2 performed that each of the new ones performs significantly better at roughly the same level with no obvious differences than the original (p < .01). Presenting the sign in two parts between them. In spite of the poor performance of the has enabled the user to rule out the possibility that existed original Series 1 sign in Experiment 1, the much larger with the original sign that what was being negated was sample of respondents used for Experiment 2 showed being within the 50m limit rather than being outside it. that it, as well as the redesigned Series 3 sign, performed There were nevertheless several respondents that were still at a level that would pass the ISO criterion for acceptance confused. A further redesign could make the water’s edge as a safety sign for use without supplementary text. look less like a wharf or weir and more like a beach.

In determining a preference between the Series 2 and to the efficacy of the two-part symbol in drawing atten- Series 3 signs we should note that the Series 3 sign uses a tion to a relatively small detail. Incorrect responses to the negating device that is used in the ISO standard for public new sign included “Make sure it’s fully inflated,” as well as information symbols, ISO 22727, whereas there is no several “Don’t use this device if you’re too fat” responses. precedent for placing an annulus and slash over part of a symbol as in the Series 2 version. The Series 3 sign is also Sign 6: Ensure that the device is not too loose consistent with the tick and cross devices used in the new This sign posed a difficulty in that there was some doubt versions of Symbols 4, 5 and 6 and should therefore be as to its precise reference. In the original document it the preferred one. It is also the only one to reach the 86% was described as “Do not sack through—regard proper criterion required to enable the sign to be used alone. fit,” which we interpreted as meaning “Ensure that the device is not too loose”. A subsequent revision, produced Sign 4: Do not jump if water is not clear after the present research was begun, substituted “Risk of Only one alternative two-part sign was produced. As the getting entrapped if size is not appropriate”. Whereas the original Series 1 sign was correct 8% of the time and the first definition implies a warning against the device being new one 73%, the new one’s performance is significantly too loose, the second also implies a warning against its and dramatically superior (p < .01, one-tailed Fisher’s being too tight. In our scoring we scored as correct any exact test). The original symbol has a critical element reference either to ensuring that the device was not too that is particularly poorly designed, namely the line loose or to ensuring a proper fit. Most of the correct with arrow element which looks more like a spear, but responses were along the lines of “Watch out, you might beyond that the number of elements in the original sign get stuck” or “Warning, you might fall through”. combined with the number of possible action interpreta- The performances of the Series 1 and Series 2 versions tions leaves the user with a difficult puzzle. Which of all of Sign 6 were almost identical even though the second those aspects is being negated? By turning the sign into was rendered in the correct ISO color scheme and a two-part symbol showing both the desired and the without the misleading dotted line that many in the undesired situations the user’s attention is immediately original Experiment 1 investigation thought was a rope. directed to the critical element. That element was not The Series 3 symbol was the two-part redesign which correctly interpreted by some respondents who thought performed significantly better than the original Series 1 it simply referred to the water’s depth rather than to the sign (p = .02, one-tailed Fisher’s exact test). possible existence of underwater hazards, but at least their interpretations in that case, such as “Don’t jump General discussion into shallow water,” would be safe. Through a judicious redesign process we have improved Sign 5: Ensure that the device is not too tight the performance of five of the six proposed water safety The original Series 1 sign was totally obscure in that no signs. This has been achieved in one case by a simple one gave a correct response to it with almost half giving redesign of a confusing element within the original up with a “Don’t know” response. The one new two- symbol. The element-description protocol of ISO 9186-2 part sign was significantly superior (p < .01, one-tailed was instrumental in drawing attention to this single Fisher’s exact test) with 78% correct, a result that attests confusing element.

The remaining four symbols were improved dramati- tation are probably irrelevant to the user’s successful cally by redesigning them as two-part symbols show- interpretation of the symbol sign’s message. ing a tick adjacent to the desired circumstance and a A final word of caution is appropriate, namely to cross adjacent to the undesired one, thus allowing users point out that the testing associated with the pres- to deduce which element is the one to which the sign ent signs was carried out only in The Netherlands and applies. Australia. Further research in other cultural contexts may The two-part redesigns we have produced are all shed additional light on the cognitive processes involved safety signs. If a sign designer wishes to comply with in interpreting both one-part and two-part symbol signs. the ISO/TC145 guidelines for the design of safety signs then these two-part signs would not be possible. It is our Acknowledgements recommendation that ISO should consider implement- ing an appropriate safety sign protocol to provide for We thank the information design firm Mijksenaar them. A traditional single-part sign, if a comprehensible (www.mijksenaar.com) for their generous contribution of design one can be successfully produced, is the simplest option, time and expertise in developing our symbols. Without their as- sistance this project would not have been possible. but where this has proved not possible our results show that a two-part sign may succeed. From having to puzzle over a range of symbol elements and related behavioral References interpretations the user’s attention is, with a two-part Adams, A. S. (1999). Usability testing in information design. In: symbol sign, immediately directed to the salient aspect. H.J. Zwaga, T. Boersema & H.C.M. Hoonhout (Eds.), Visual in- A recent example has come to our attention relat- formation for Everyday Use: Design and Research Perspectives. ing to the safety instructions for using a chain saw. The London: Taylor & Francis, 3–20. instruction manual stresses that the chain saw should CEN prEN 15694-2:2007. Floating leisure articles for use on and in be always used with two hands. The only options for the water – Part 2: Consumer information. Brussels: European symbolizing this that are provided for in the present Committee for Standardization. ISO guidelines would involve two separate symbol signs, ISO 22727:2007. Graphical symbols – Creation and design of public information symbols – Requirements. Geneva: International one showing a red annulus and slash over an image of a Organization for Standardization. person holding the chainsaw with one hand and, next to ISO 3864-1:2002. Graphical symbols – Safety colors and safety it, a separate white-symbol-on-blue-background manda- signs – Part 1: Design principles for safety signs in workplaces tory-action symbol sign showing two hands holding the and public areas. Geneva: International Organization for chainsaw. It would be much simpler to have a single two- Standardization. part symbol with a tick next to the two-handed opera- ISO 3864-3:2006. Graphical symbols – Safety colors and safety signs tion and a cross next to the one-handed operation. – Part 3: Design principles for graphical symbols for use in safety signs. Geneva: International Organization for Standardization. In developing an appropriate protocol for two-part ISO 7001:2007. Graphical symbols – Public information symbols. signs a standard would have to be developed for the Geneva: International Organization for Standardization. appropriate shape and color of such signs but, as we have ISO 7010:2003. Graphical symbols – Safety colors and safety signs shown with our simple “public information” versions of – Safety signs used in workplaces and public areas. Geneva: two-part signs using a plain background and rectangular International Organization for Standardization. shape, the details of the color and shape of the presen-

ISO 9186-1:2007. Graphical symbols – Test methods – Part 1: Contact Address Methods for testing comprehensibility. Geneva: International Organization for Standardization. Austin Adams ISO 9186-2:2008. Graphical symbols – Test methods – Part 2: School of Psychology Method for testing perceptual quality. Geneva: International James Cook University, Singapore Organization for Standardization. 600 Upper Thomson Road Singapore 574421

About the Authors Theo Boersema Faculty of Industrial Design Engineering, Delft University of Austin Adams has been retired for 10 years Technology from an academic life teaching ergonomics and Landbergstraat 15, related subjects in the School of Psychology at 2628 CE Delft, the University of New South Wales but is now The Netherlands re-entering the workforce at James Cook Uni- versity, Singapore Campus, where he will be teaching research Meijer Mijksenaar methods within the Psychology program. His research has been Mijksenaar with respect to warning signs – when do we comply and when Amstelveste, Joan Muyskenweg 22, not? Austin is chair of a Standards Australia committee on water 1096 CJ Amsterdam, safety signs and is a member of several signage-related ISO The Netherlands committees. Email: [email protected]

Theo Boersema is an assistant professor in ergonomics at the Faculty of Industrial Design Engineering of Delft University of Technology in The Netherlands. His research activities are in the domain of the ergonomics of visual information. He is a member of Dutch (NEN) and international (ISO) committees and working groups on graphical symbols. Email: [email protected]

Meijer Mijksenaar recently graduated in graphic design from the Utrecht School of Arts. For his graduating project he designed animations in which the cause and effect of annoying behaviour in public transport is shown using only pictograms and symbols normally seen in that context. He is now em- ployed as a junior designer at Mijksenaar. Email: [email protected]