As far as the genuine use of a black and white or grayscale mark is concerned - the actual use has to show
|• A change only in colour does not alter the distinctive character of the trade mark, as long as the following requirements are met:
a) the word/figurative elements coincide and are the main distinctive elements;
b) the contrast of shades is respected;
c) colour or combination of colours does not possess distinctive character in itself and;
d) colour is not one of the main contributors to the overall distinctiveness of the mark.
|a CTM as registered
|A trade mark as used
However if you are going to register in colour or even grayscale then better get your colours right and replace the registrations if they change. Still it has always been good advice to register your trade mark as it is used and then there are no problems in proving genuine use. However trade mark agents find it irresistible to be able to oppose rather more than the identical mark as used on the basis that it is identical to the partial signs they have registered.