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Commentary - Use
    [p.1179] Annex I, Article 4 -- Use


    General remarks

    4053 The whole of the distinctive emblem must be visible from all directions if it is to be identified at a glance, without hesitation. This was demonstrated by the ICRC visibility tests carried out in 1972 and 1976 as well as by the tests of the [p.1180] emblem's visibility from the air conducted in March and May 1936 by the Dutch and Swiss Air forces. (1)

    4054 The ICRC's report on its own tests (D. 1291) was communicated to the specialists attending the 1972 Conference of Government Experts. The report gives the size of the emblems and the distances, ranging from 100 to 1,000 m, at which they were observed, together with the type of material used to make them. The red cross measured 80 x 80 cm and was displayed on a white 100 x 100 cm panel. The red crescent was 80 cm high. Different types of panel (wood, cardboard and metal), all with plane surfaces, were used. Ordinary paint was used for some of the signs, while others were made out of ordinary or fluorescent self-adhesive coloured plastic. Phosphorescent colours were tested as well as red and white retro-reflective materials, and experiments were carried out with various combinations of the above-mentioned materials.

    4055 Further details will be given later of these tests, which also included the observation, from distances of less than 80 m, of the small distinctive emblem on flags, armlets, tabards, helmets, stretchers, tents and medical vehicles. The observations, which were made during the day, at twilight and at night (moon in the first quarter), in clear weather, showed that theses small signs were inadequate, particularly on the armlet.

    4056 At night, visible light projectors and pencil beams (pocket torches) were used to view the signs; infrared detection of the sign was tested by means of active electro-optic observation. Under infrared radiation, as in the case of visible light, the judicious use of reflectorized materials may considerably improve colour contrast and visibility range. Retro-reflective material consists of microscopic spherical glass balls embedded in sheets or strips of self-adhesive cloth or plastic and secured by a film of special transparent material. It should be borne in mind that the reflected light ceases to be visible if the observer moves outside the cone of about 4 degrees formed by the angles of incidence. The eyes of a cat, which are natural retro-reflectors, have optical characteristics on which the invention of retro-reflective material was based. (2) Retro-reflective materials are widely used, particularly for road signs.

    Paragraph 1

    4057 The flag has always been -- and still is -- an excellent signal since, taken together with its holder and pole, and provided it is large enough (about 100 x 100 cm), its height makes it an ideal stimulus for the naked eye.

    4058 Flying the white flag struck with the red distinctive emblem is tantamount to sending a visual signal which will be seen more clearly from below by a distant observer than a less conspicuous sign. Thus ICRC vehicles operating in combat areas are not only marked with distinctive signs that are as large as possible and [p.1181] are visible from the front, the back and both sides; they also fly a 100 x 100 cm red cross flag from a vertical mast mounted at the rear.

    4059 If the distinctive emblem is not displayed on a flat surface, it will not be seen in full at a glance, for part of it will be concealed by ridges or broken angles. One example is the sign displayed astride the summit of a roof which, because it is broken, is not identifiable by an approaching aircraft. It has to be seen from directly above in order to be identified. The same applies to a sign straddling the ridge of a medical tent, which is not fully visible to an observer at ground level and therefore cannot be identified beyond any doubt, even at the relatively small distance of
    about 200 m.

    4060 In order to be visible from every possible direction, the distinctive emblem should therefore be displayed on flat surfaces facing these directions, such as the side walls and yard of a building, each slope of a roof, the walls of a medical tent, as well as on angled panels placed near the buildings. Such surfaces can generally receive large markings which are visible from afar. The ICRC uses 5 x 5 m and 10 x 10 m red cross flags with no mast for this purpose.

    4061 The tests conducted by the ICRC on the visibility of the distinctive emblem displayed on moving vehicles showed that emblems measuring 50 x 50 cm or less were quite inadequate when seen from constantly changing angles. Such emblems become difficult to distinguish at about 250 m. Medical vehicles should display red cross emblems which are as large as possible, depending on the type of vehicle; in other words, they should cover the full height of the bodywork, even if a small part of the sign is distorted or broken by the line of the vehicle.

    4062 White panels measuring 100 x 100 cm with an 80 x 80 cm distinctive emblem, displayed on the front, rear, sides and roof of a medical vehicle, provide an easy means of identification up to 300 m. On a moving vehicle in clear weather, the visibility of the sign becomes fair to poor at more than 300 m and nil at about 500 m.

    4063 Various colouring matters were tested in order to assess their effect on the visual range of the emblem; the results of these tests are discussed in the articles published in the International Review of the Red Cross on the modernization of protective markings and signalling and the colours of the distinctive emblem. (3)

    4064 Phosphorescent paint, which accumulates light falling on it, emits only a small quantity of light in obscurity and is therefore not a great deal of use. Fluorescent paint, which is activated by ultra-violet rays, is very effective, especially at dawn or twilight when ultra-violet radiation in the atmosphere increases for a short time and makes fluorescent colours very bright. A fluorescent red cross on a 100 x 100 cm panel remains visible and identifiable at 200 m until night has completely fallen; it is still visible, although not necessarily identifiable, at 500 m.

    4065 Like retro-reflective material, fluorescent paint must be used judiciously so as to preserve the contrast between the red sign and its white ground. The same applies to cat's eyes, which are used for marking roads because of their reflective properties. Studies and research still need to be conducted in order to identify the red andwhite substances which best meet all the requirements of the distinctive [p.1182] sign, namely, visibility from as far away as possible, by day and by night, in bad weather, under infrared observation, or using light amplification glasses and increasingly sophisticated military electro-optic systems.

    Paragraph 2

    4066 Like military medical and religious personnel, permanent or temporary civilian medical and religious personnel are entitled to wear the distinctive emblem. It is worth mentioning in passing that the ICRC tests demonstrated the ineffectiveness of the armlet at a distance:

    -- the armlet which medical personnel are required to wear on the left arm (First Convention, Article 40 ) cannot be identified at less than 80 m, if the person wearing it is either squatting or seen from the right, the front or behind;
    -- the prescribed armlet, marked with a red cross or crescent about 8 cm in diameter, worn on the left arm and seen from the left, is not identifiable at a distance of more than about 80 m;
    -- if the protected personnel wear an armlet on each arm, they are easier to identify, seen in profile, at a distance of less than 80 m; they are far more difficult to identify from the front and the rear and cannot be distinguished at all at more than 80 m.

    4067 Paragraph 2 seeks to remedy the shortcomings of the armlet as a means of identification by proposing, subject to the authorization of the competent authority, that military and civilian medical and religious personnel should be provided with additional means of identification restricted to personnel carrying out their humanitarian duties in the combat zone.

    4068 As far as possible, therefore, protected personnel are to be supplied with headgear and clothing bearing the distinctive emblem, thus according official status to the practice which had already become common during the Second World War of using white-painted helmets with the distinctive emblem marked on the back, front, sides and top.

    4069 Tabards, coats and other white clothing bearing the distinctive sign are also authorized under the above-mentioned conditions.

    4070 The necessarily small size of the distinctive emblem on headgear, tabards and other items of clothing limits the distance at which personnel are identifiable. According to the ICRC's tests, these distances are as follows:

    1) for a tabard made of ordinary material and bearing the sign back and front: at 80 m, identification easy from the front and the rear, difficult from the side; from 80 to 150 m, visibility is only fair, becoming poor at more than 150 m because the red cross is too small.
    2) The above comments apply to white outer clothing marked back and front with red crosses.
    3) The comments made in connection with the armlet apply also to white helmets marked with red crosses; the latter, which measure about 8 cm, become invisible at 80 m. The white helmet is identifiable by its light colour (immaculate surface) up to about 150 m.

    [p.1183] 4071 The tests showed that a red crescent of the same height as the cross is more difficult to identify because it has a smaller red area.

    4072 The personnel carrying out their humanitarian duties in the combat zone are best protected by the conclusion of truce agreements enabling the Parties to the conflict to care for the wounded and evacuate them together with the dead. Even in these conditions, medical and religious personnel must be provided with the equipment proposed in paragraph 2, in order to avoid any misapprehension.

    ' Ph. E. '


    NOTES (1) [(1) p.1180] Cf. general introduction to the commentary on Annex I; supra, p. 1141, and introduction to Chapter 11, supra, p. 1167;

    (2) [(2) p.1180] Cf. Ph. Eberlin, "Modernization of Protective Markings and Signalling", op. cit., pp. 72-73;

    (3) [(3) p.1181] Cf. supra, Art. 3, footnotes 6 and 2, pp. 1177 and 1174;