INSTRUMENTAL COLOUR MEASUREMENT AND CONTROL 281 THE LECTURER: I am rather surprised that the Colormaster is not able to fairly accurately estimate colour differences on patterns with the sort of reflectance you mentioned, i.e. 20%. One has to accept that for very dark colours, •vhen the reflectance is very low, the sensitivity of the instrument begins to be a slight problem, but I do not consider them any more significant than the problems that occur in visual assess- ment at low reflectance. I can not really offer an explanation for your observations. As far as we could discover there have not been any limitations for any particular type of colour with the instruments that I have mentioned, including the Colormaster. MR. j. M. TRIGGLE: Did you say that the efficiency of the red and blue response is in any way inter-dependent upon the green response in the Colormaster? In other words, that if the efficiency of the green will go down, the efficiency of the red and blue will go down as well? THE LECTURER: There is no inter-dependence of the red, green and blue responses. The responses of the Colormaster are designed to be approximately equal to that of the eye. And this is so, of course, with other instruments, the colour eye and the Zeiss Elrepho. It is true to say that the Zeiss Elrepho and the Color-Eye do approximate better to the average eye characteristics but I do not think that this would make any great difference when you are comparing non-metameric colours. MR. j. M. TRIGGLE: May I just substantiate what I said. This work was carried out in conjunction with the Paint Research Station. and we intentionally adulterated some mascaras and eye cosmetics by adding red pigment the Colormaster did not change its reading with the red filter at all, although the colour change was visually quite perceptible. THE LECTURER: I find this quite surprising, but it may be worth looking more carefully at the method of presentation of the samples to the Colormaster which may be giving rise to errors of reading large enough to mask the small colour differences. DR. j. J. MAUSNER: It may well be that the difficulties described by Mr. Triggle are due to the fact that a colour instrument which measures three definite wave- lengths in a spectrum is just not sensitive enough, and one can well envisage a theor- etical case of a colour where the reflectance at three different wavelengths are equal to standard, but where the rest of the colour spectrum is different. THE LECTURER: This sort of measurement is only suitable for non-metameric matches. If you are quite sure that the colorants in the standard colour and the pro- duction are the same, then you should be fairly safe in looking at measurements at, say, three wavelengths and comparing these, since in an identical match the reflect- ances at tlm-ee wavelengths should be the same. The Colormaster, however, does not have these defined wavebands of measurement in fact it looks at colour with a response which extends right over the spectrum. True that you have a green, a red and a blue filter and they have predominantly sensitivities in those regions of the spectrum, but nevertheless they do extend over a broad region.

Society of Cosmetic Chemists of Great Britain PUBLICATION PRIZE: oe100 AWARD Each year the Society publishes five of the thirteen issues of this Journal and is proud of the standard that has been reached in these. In this, as with all other activities of the Society, Council take the view that we can always do better. To stimulate interest in preparing original papers of ever increasing quality, Council have decided to award a prize for the best scientific paper to be submitted for publication in the British editions of the Journal in each calendar year. The conditions for the award are:-- 1. Consideration will be given to all original scientific papers sub- mitted, but only in exceptional circumstances, to dissertations and review articles. The Medal Lecture and preliminary communications will not be eligible. 2. Papers must have been submitted during the current calendar year and not previously published elsewhere. 3. Only papers as defined above and submitted for the British editions will be eligible. Special application to be considered will not be necessary. 4. Judging will be by a committee consisting of the President, the Chairman of the Scientific Committee, and the Hon. Editor. They will seek outside and specialised advice as they see fit. Their decision will be submitted to Council for ratification. 5. The prize will be oe100. Council hope that this Award will increase the incentive to prepare original papers of high quality for the Journal. 283