GB2286511A - Computerised colour selection tool - Google Patents

Abstract

A computerised colour selection tool (1) for assisting an unskilled person in the choice of a colour from a wide range of alternative colours. The tool has a preliminary selection means (20 and 6) which displays a first range of colour samples (for example 26A to 26F and 24C to 28C) representing all visible hues (i.e. from yellow via red, blue and green to yellow) and each hue being shown with alternative degrees of blackness and has means (6) enabling one of these colour samples to be selected as a link colour. Selection of a link colour causes an immediate and simultaneous display of a further display (22) of alternative colour samples but which are more closely adjacent the link colour and from which a final choice of colour can be made. Varying the choice of link colour immediately produces corresponding alternative displays so enabling the unskilled person to appreciate the consequences of the variation without having to discern or remember subtle differences in colour. <IMAGE>

Description

COLOUR SELECTION TOOL This invention relates to a colour selection tool for facilitating the selection of a colour from a predetermined range of colours.

By "a colour" is meant a colour as perceived by the human eye as distinct from a colour as measured by optical instruments. Instruments measure colour in terms of the wavelength and intensity of the light received by the instrument whereas the eye perceives colour not only according to wavelength and intensity but also according to the different physiological responses to different wavelengths or combinations of wavelengths. Several systems exist which attempt to define colour as perceived by the eye. One such system is known as the NCS or Natural Colour System and it is fully described in Swedish Standard SS 019102 published by the Standardiseringskommissionen i Sverige of Box 3295, S-10366 Stockholm Sweden or in the "Colour Dimensions Colour Atlas" published by Imperial Chemical Industries Plc of Wexham Road, Slough, England, the contents of which Atlas are herein incorporated by reference.

The NCS defines colour as perceived by the eye in terms of three colour parameters which are hue, chroma and blackness. Hue is a measure of the yellowness, redness, blueness or greeness of a colour and it expresses colours (except pure white, black or greys) as either pure yellow, pure red, pure blue, or pure green or as combinations of pure yellow and pure red, pure red and pure blue, pure blue and pure green or pure green and pure yellow. Chroma is a measure of the intensity of a colour, that is to say whether a colour is a pale or strong shade. Blackness (as perceived by the eye) indicates the darkness or lightness of a colour, with pure black at one extreme and pure white at the opposite extreme. A circle of hues (known as the "Colour Circle") is illustrated on page v of the Colour Dimensions Atlas which shows the circle extending from pure yellow via pure red, pure blue, pure green and their intermediate hues back to pure yellow. Variations in chroma and blackness for a particular hue are shown on pages 1 to 40 and achromatic variations in blackness (i.e.

variations from pure white via greys to pure black) are shown to the left of page 41.

It is estimated that the human eye is capable of distinguishing of the order of sixty million different colours although the limitations in dye and pigment technology reduce the range of colours that can be produced commercially for uses such as colouring paints or fibres.

Even so over 16000 colours are available and a typical range of colours offered by paint manufacturers might contain several thousand (often 2000 to 7000) colours.

Whilst skilled specifiers of colour such as architects and textile designers can cope with such a wide choice, it has been found that unskilled people in an ordinary retail shop become confused and frequently make choices they later regret. It has now been discovered that the problem arises because the unskilled mind is unable to discern subtle differences in hue, chroma or blackness unless colour samples are placed very close to one another. Moreover, the unskilled memory has great difficulty in remembering colours even for the short period of time needed to turn over the pages of a colour atlas in order to compare colour samples located on different pages. The problems of placing colour samples close together will be appreciated when it is noted that a typical sample measures 15 by 45 mm which means that samples of say 7000 commercial colours laid side by side would occupy an area of over 4.7m2. The unskilled eye will not discern or remember hue blackness and chroma accurately when traversing so large an area.

Therefore clearly some tool for facilitating the selection of colours by unskilled people is needed and several have been provided in the past.

One tool uses a mechanical disc having differently coloured portions, the relative proportions of which can be varied.

By spinning the disc, it can be made to appear to the eye as a single colour formed by the merging of the individual coloured portions. By noting the relative proportions of the colours, it is possible to select a paint recipe that will generate a close match to the colour perceived when the disc is spinning.

Such a tool is suitable for assisting the matching of colours but it offers no guidance when making an aesthetic selection of colours. This is partly because only one colour sample can be displayed at a time and partly because the tool offers no guidance to an unskilled user in deciding which of several colour components should be varied in order to achieve the colour being sought. This is particularly troublesome where a pastel colour is being sought, for the unskilled eye is particularly vulnerable to failures to discern and remember the correct differences between similar hues and/or chromas in the paler shades of colour.

A later tool implemented on a computer system, displays on a colour monitor an initial range of colours in the form of a so-called colour wheel. The colour wheel comprises a plurality of concentric circles composed of contiguous colour samples in which hue varies circumferentially around the circles and in which colour samples of the same hue are located on a common radius with their chroma varying radially across the wheel so that the innermost circle comprises samples of the highest chroma (strongest shade) whilst the outermost circle comprises samples of the lowest chroma (palest shade). To accommodate the display of colour samples of different blackness, a facility is provided for switching between a "light" wheel comprising colours of relatively low blackness (a high proportion of white) and a "dark" wheel comprising samples of relatively high blackness. The user may select a colour sample from the wheel using a pointing device. Once a colour sample has been selected in this way, the wheel is replaced on the monitor by a second more restricted range of colour samples arranged in three grids of colour samples arranged side-byside. Each grid is composed of twenty-five colour samples arranged in a 5 by 5 square. The centre sample of the centre grid is the same colour sample as that selected from the wheel.

Colour samples adjacent the centre sample have the same hue but vary stepwise in chroma or in blackness. Samples to the right of the centre sample show increasing chroma whilst those to the left show decreasing chroma. Samples above the centre show decreasing blackness whilst those below show increasing blackness. The two flanking grids each have centre colour samples of hues closely adjacent to the hue of the centre sample of the centre grid. Again chroma varies stepwise in colour samples to the left and right of each centre sample whilst blackness varies stepwise in colour samples above and below each centre sample. The variations in chroma which occur in the colour samples to the left and right of each centre sample means that the centre sample of the centre grid is spaced from the centre samples of the flanking grids by colours samples which vary in chroma. Small adjustments can be made to the chroma and blackness of colour samples shown around each centre sample of a grid by varying the size of the steps of change in chroma and blackness between each colour sample within the grid. Small adjustments to the hues shown in the flanking grids can be made by varying the size of the step in hue between the hue of the centre grid and that of a flanking grid. Additionally, the hues displayed in the grids can be varied using a so-called centering operation.

In the centering operation, a colour from the displayed grids (other than the centre colour of the centre grid) is chosen and then the chosen sample is made the centre colour of the centre grid. Larger adjustments require a return to the initial choice of colours from the colour wheel and therefore the making of a totally new selection.

The computerised system provides a selection of one from two alternative blacknesses which is made first followed by a selection of che required hue and chroma. This does not lead to a significant improvement in the extent to which unskilled people are satisfied with their choice of colours. The reason for this is two fold. Firstly as already indicated, the unskilled eye cannot remember accurately differences in the various colour parameters.

Secondly it has now been appreciated that variations in one parameter will cause the other two to be perceived in a way which cannot be foreseen by inexperienced people.

Therefore an object of this invention is to provide a tool for facilitating the selection of colours from a predetermined range of colour samples by assisting the unskilled eye to discern and remember differences in colour parameters and to show immediately the consequences of varying a colour parameter.

Accordingly the present invention provides a colour selection tool for facilitating the selection of a colour from a pre-determined range of colour samples which tool includes a) a data processing arrangement for processing signals representative of a plurality of colours, b) a colour display device coupled to the processing arrangement and capable of displaying the colours as differently coloured samples and c) an operator entry device coupled to the processing arrangement for selecting the displayed colour samples and the data processing arrangement includes a preliminary selection means for causing the display device to display a first range of colour samples of different hues and to indicate at least one link colour sample of a selected hue and blackness, the link colour sample being selected in response to a link colour selection signal from the entry device characterised in that the preliminary selection means causes the display device to display simultaneously more than one blackness for each hue and the data processing arrangment also includes further selection means responsive to the selection of the link colour sample so as to cause the display device to display simultaneously with the display of the first range a second range of colour samples comprising the link colour sample and other colour samples which differ in chroma (preferably in both hue and chroma) from each other and from the link colour sample and wherein the selection of an alternative link colour sample causes the alternative link colour sample to be displayed as the link colour sample in the second range together with an alternative range of other colour samples.

The preliminary selection means of the tool enables unskilled people to make a first and probably tentative selection of hue and blackness when selecting the link colour sample and then they can use the simultaneous display of the second range of colour samples to observe immediately a range of alternative chromas for the selected hue and blackness plus a range of preferably closely related (preferably at least 2 and usually not more than 10) hues of various chroma. Alternative link colour samples can be easily selected and the consequences of an alternative selection will be seen immediately in the second range. Most importantly, a person can oscillate back and forth between alternative link colour samples and simultaneously produce a corresponding oscillation in the second range displayed. The ability to see alternative hues and chromas displayed closely together combined with the ability to oscillate rapidly between the alternative selections of hue and blackness greatly facilitates the discernment of differences between colours, avoids the need to remember the differences precisely and illustrates the consequences of varying colour parameters.

Preferably the preliminary selection means enables the unskilled person to select a colour sample of a particular hue first and then to complete the selection of a link colour sample by choosing a sample of a preferred degree of blackness. Preferably once the hue has been selected, all samples having that hue (but with different blacknesses) are emphasised, for example by dimming the illumination of colour samples having the unselected hues. However, since most first selections of hue are tentative, it has been found that the selection of a satisfactory alternative hue is assisted if a limited number (preferably 2 to 6) of adjacent hues of various blackness are also emphasised simultaneously with the link colour sample. These adjacent hues define a zone among the colour samples displayed which will move about the display if the person subsequently decides to choose a link colour of a different hue. A subsequent choice of a link colour of a different hue is facilitated if there is also emphasised one colour sample of every hue of similar blackness appearing in the display.

It is particularly preferred that the preliminary selection means causes the first range of colour samples to be displayed in the form of a colour wheel comprising concentric circles of colour samples which vary in hue circumferentially and in blackness radially. Usually the wheel will comprise from 30 to 50 different hues and from three to seven concentric circles corresponding to different blacknesses. Preferably, the wheel is traversed circumferentially to select a hue and then radially to select a blackness. The radius comprising the selected hue together with from two to six adjacent radii may be emphasised by dimming or extinguishing the illumination of other radii. Preferably in addition one complete circle of colour samples of similar blackness content is emphasised to facilitate a choice of an alternative link colour.

Usually this circle will have an inner radius about equal to half the radius of the wheel, (i.e. it should lie in a position about half way between the centre and the circumference cf the wheel.) It has been found empirically that the reliability of selections made by unskilled people can often be enhanced if the colour samples of a particular hue radius vary not only in blackness but also contain some samples which have different chroma. In certain instances which can only be determined by experience, it has been found that small variations in chroma actually assist in identifying the aesthetically wanted hue even though the exact opposite (i.e. increased confusion ) might have been expected.

The invention will now be described by way of example, with reference to the drawings in which, Figure 1 is a block diagram of a colour selection tool constructed in accordance with the invention and Figure 2 is a typical display output of the tool of Figure 1, and Figure 3 is a diagrammatic representation of a page from Natural Colour (NCS) Colour Atlas With reference to Figure 1, a colour selection tool (1) comprises a central data processing unit (CPU) 2 which may be a microcomputer such as an IBM- compatible Personal Computer. The CPU 2 is connected to operator entry devices which are a keyboard 4 and a pointing device 6 such as a mouse or a tracker-ball. Output from the CPU 2 is provided via a graphics adaptor 8 connected to a colour visual display unit (VDU) 10. Optionally, the CPU 2 may also be connected to a printer 12 and/or a spectrophotometer 14.

The CPU 2 includes storage means (not shown) such as a hard disk for storing software and/or data.

Figure 2 shows a typical output display from the VDU 10.

A first range of colour samples in the form of a colour wheel 20 is displayed on the left side of the display and on the right is displayed a second range of colour samples in the form of a grid of colour samples 22. Along che bottom of the display is a button-bar 23. The display in conjunction with the pointing device 6 forms a graphical user interface (GUI) for the tool. The colour wheel 20 comprises centre circle 26 (only one sector of which is shown in detail) composed of a series of forty discrete colour samples including samples 26A to 26F which have maximum chroma and no blackness and which cover the whole NCS colour spectrum from pure yellow via pure red, pure blue and pure green back to pure yellow.

In use, centre circle 26 is emphasised by dimming or extinguishing many of the colour samples in other circles 24, 25, 27 and 28. These other circles 24, 25, 27 and 28 are located inside or outside of centre circle 26 and they contain colour samples (for example 24C, 25C, 27C and 28C) of different blackness arranged so that all colour samples having the same hue lie on common radii which are denoted the A, B, C, D, E and F radii.

In order to select a link colour sample (say sample 27C), pointing device 6 is traversed circumferentially around centre circle 26 and it emphasises different sectors of colour samples as it travels. When the desired hue represented by the sample 26C is reached, pointing device 6 is stopped. At this point, not only is colour sample 26C emphasised by being more brightly illuminated relative to dimmed samples, but the other colour samples on the same radius (i.e. 28C, 27C, 25C and 24C) are also emphasised in the same way as are the colour samples on four adjacent radii, that is to say the radii including samples 26A, 26B, 26D and 26E.

Having made a selection of hue 26C, pointing device 6 is then moved to the colour sample having the desired blackness (say sample 27C) whereupon pointing device 6 signals that this is to be the link colour sample Accordingly colour wheel 20 plus pointing device 6 provide means enabling an operator to make a preliminary selection of a colour (i.e. the link colour) in terms of hue and blackness.

As soon as pointing device 6 signals the choice of a link colour, a corresponding range of colour samples in the form of grid 22 is simultaneously displayed as the second range of colours shown on VDU 10. The unskilled person can then use pointing device 6 to select a final colour sample from grid 22. Alternatively, (if the first selection of a link colour sample was tentative), the pointing device 6 can be moved elsewhere on the wheel 20 to select an alternative link colour sample (say 26A) which in turn causes an alternative grid of colour samples (not shown) to be displayed simultaneously on VDU 10. Choosing sample 26A as the link colour instead of sample 27C involves choosing different hue and blackness parameters. The consequences of varying these parameters are simultaneously illustrated by new samples shown in grid 22 and so the consequences become immediately apparent even to the unskilled eye. If the unskilled person is still unsure of his choice, he can move the pointing device 6 again and in particular he can move back to his first choice of link colour sample 27C.

In this way it is possible to oscillate between link colour samples in colour wheel 20 to cause simultaneous oscillation between alternative grids 22 so as to facilitate a comparison. For example he can oscillate back and forth between alternative choices of link colour samples until a satisfactory final choice is made.

The grid 22 of colour samples contains five columns 30A to 30E of usually eleven colour samples. The central column 30C contains the link colour sample 27C plus colours of the same hue and blackness as the link colour sample but with these other samples varying in chroma. Ideally the columns would contain colours having chromas of 5, 10, 15, 20, 30, 40, 50, 60, 70, 80 and 90 according to the NCS scale but it is not always possible to supply the complete range owing to a lack of suitable pigments or commercial formulations for making certain shades so some positions 31 may be unfilled. The flanking columns 30A, 30B, 30D and 30E contain colour samples having the same blackness as those of column 30C but which have four closely adjacent hues, that is to say the hues differ from that of link colour sample 27C by + 10 or + 20 on the NCS scale. A group of supplementary colours 32 are provided beneath grid 22.

These are colours whose NCS hue and chroma values do not fit precisely into grid 22 as defined above but which have been included because they have been proved to be very popular for a variety of historical or commercial reasons.

Traversing pointing device 6 circumferentially around wheel 20 changes the sectors of radii which are emphasised and causes a corresponding shift in the range of colour samples displayed in grid 22. For example an anti-clockwise movement by pointing device 6 from sample 28C to sample 28D will cause a shift from left to right of columns 30A to 30E in grid 22 with column 30E disappearing to be replaced on the left by a new column of colour samples having the same hue as colour sample 28F in wheel 20. A clockwise movement of pointing device 6 would produce a corresponding shift from right to left of columns 30A to 30E with a corresponding loss and replacement of column 30A.

If required, the pointing device 6 can be adapted to cause similar shifts in grid 22 and the emphasised sector of wheel 20 when pointing device 6 is traversed from column to column across grid 22 whereupon once again the consequences of varying colour parameters are immediately apparent to unskilled people. However the provision of a capability to cause shifts in grid 22 and the emphasised section of wheel 20 by traversing the pointing device 6 across grid 22 introduces a risk that an unskilled person might cause such shifts unintentionally. To prevent such unintentional use of pointing device 6, it is preferred that it be provided with a switch which has to be positively switched on by the person in order for pointing device 6 to cause shifts when traversing grid 22. Usually the switch will be biassed to the off position so that a continuing positive intention to use pointing device 6 in this way is required of the person.

The colour selection tool as illustrated with reference to Figure 2 also comprises a button bar 23 for performing certain additional functions when a particular colour sample has been selected from grid 22. For example, the colour may be shown on the full extent of the VDU screen by activating the "flood fill" button using pointing device 6.

This causes a "saturation" of the eye with the selected colour which is valuable since the impact of a colour varies according to how large a sample is viewed.

Alternatively, by activating the complement" button, a complementary colour may be calculated and shown or by activating "NCS Code", an NCS notation for a colour can be provided and/or entered. The "mix" button may be activated to obtain information relating to the type of paints available in that colour.

The button-bar 23 may also be used instead of pointing device 6 to step the grid 22 left or right one column 30 at a time or to step the grid backwards or forwards through columns 30 of lesser or greater blackness respectively. As the grid 22 is stepped left or right, a corresponding shift occurs in the emphasised sector of wheel 20.

In a preferred embodiment, the colour selection tool is also provided with a spectrophotometer 14 for measurement of the colour of some article for which a colour match is required. This option may be activated using the "match sample" button on the button bar 23. The tool may then be arranged to display a colour sample of the closest colour match available. The match will be displayed as one of the supplementary colours 32 or in the central column of the grid 22 with the other columns and the emphasised sector of wheel 20 being correspondingly aligned.

More reliable selection of colour has found to be possible if the colour samples representing a particular hue located on a radius of colour wheel 20 vary not only in blackness but also include some empirically chosen variations in chroma. The precise variations in chroma which have been found to be beneficial have to be chosen by experiment since the criteria for their choice are largely subjective.

Guidance for choosing apropriate variations in hroma can be obtained from Figure 3.

Figure 3 shows a typical page from the ICI Colour Dimensions Atlas which carries colour samples of a particular hue and five of these samples will be chosen for display on the corresponding hue radius of colour wheel 20.

Figure 3 shows that the colour samples on the Atlas page have been notionally grouped into five areas 44 to 48 of respectively deep colours 48, bright colours 47, pastel colours 46, soft colours 45 and dark colours 44. One colour from each area is then chosen experimentally as being the most reliable indicator of the character (as judged subjectively) of all the colours in its area. The chosen colours are then used as the colours on the corresponding radius of colour wheel 20. Similar experiments are performed for every hue represented in colour wheel 20 and subjective choices of colour samples are made. The deep colours 48 are selected for display in centre circle 26.

Claims (9)

luAIMS

1. A colour selection tool (1) for facilitating the selection of a colour from a pre-determined range of colour samples which tool includes a) a data processing arrangement (2) for processing signals representative of a plurality of colours, b) a colour display device (10) coupled to the processing arrangement and capable of displaying the colours as differently coloured samples and c) an operator entry device (4, 6) coupled to the processing arrangements for selecting the displayed colour samples and the data processing arrangement (2) including a preliminary selection means for causing the display device to display a first range (20) of colour samples of different hues and to indicate at least one link colour sample (27C) of a selected hue and blackness, the link colour sample being selected in response to a link colour selection signal from the entry device, characterised in that the preliminary selection means causes the display device (10) to display simultaneously more than one blackness for each hue and the data processing arrangement (2) also includes further selection means responsive to the selection of the link colour sample so as to cause the display device 10 to display simultaneously with the display of the first range a second range (22) of colour samples comprising the link colour sample and other colour samples which differ in chroma from each other and from the link colour sample and wherein the selection of an alternative link colour sample causes the alternative link colour sample to be displayed as the link colour sample in the second range together with an alternative range of other colour samples.

2. A tool according to Claim 1 characterised in that the second range comprises an array (22) of colour samples which differ in hue in one direction and in chroma in another direction.

3. A tool according to Claim 1 or Claim 2 characterised in that the preliminary selection means enables the link colour sample (27C) to be selected by first selecting a colour sample (26C) of a particular hue and then completing the selection of the link colour sample by choosing a colour sample of a preferred degree of blackness from among colour samples (24C, 25C, 26C, 27C and 28C) of the chosen hue.

4. A tool according to any one of Claims 1 to 3 characterised in that the preliminary selection means is arranged such that once a colour sample (27C) of a particular hue has been selected, all colour samples having that hue are emphasised.

5. A tool according to Claim 4 characterised in that the preliminary selection means is arranged such that the emphasis is achieved by dimming or extinguishing other colour samples.

6. A tool according to any one of the preceding Claims characterised in that the preliminary selection means is arranged such that the first range of colour samples are displayed in the form of a colour wheel (20) comprising concentric circles of colour samples which samples vary in hue circumferentially around the wheel and in blackness radially of the wheel.

7. A tool according to Claim 6 characterised in that the preliminary selection means is arranged such that a sector of the colour wheel containing colour samples which are on radii adjacent the radius containing the link colour sample are also emphasised.

8. A tool according to Claim 7 charactersied in that the preliminary selection means is arranged such that a central circle (26) of colour samples is emphasised at all times whilst the tool is in use.

9. A tool according to any one of the preceding Claims having a second range of colour samples arranged in columns (30) in which each column contains samples of a single hue, characterised in that the tool is responsive to a movement of the operator entry device (6) from column to column to cause a shift in the columns displayed and in the emphasised portion of the first range (20) of colour samples.