Updating the color profile failed for printer
In ISO 13655, the observer and illuminant data are pre-multiplied and for ICC applications these are what should be used (unless you have a spectrophotometer that measures at 5nm bandpass ? But if you don't have those a good approximation can be obtained by using data interpolated from the 5nm interval data which CIE publish and which can be found in any good book on colour, and on a number of websites such as The coefficients of the matrix depend upon the illuminants one is converting to and from and the assumptions one wants to make about the best 'visual space' for doing this.The most popular among many users seems to be the linear part of what is known as the Bradford transform, though more recent transforms perform slightly better.You will also find some useful material in the links we give from our web-site.
There is more information about CIE colorimetry on our web-site and there are some good books about (see the list above). You then need to normalise the data so that you get 100 for Y for the reference white - usually the perfect diffuser, but it may be white paper. Various methods are in common use - most of which employ a 3 x 3 matrix transformation.In a proof matching situation there is always a potential risk if the papers used for proofing and printing have radically different fluorescence. Colour is the sensation achieved when light falls on the retina of the eye.If you use relative colorimetry the unprinted paper will be free of ? dots in both cases but because the inks do not generally fluoresce all but the lowest chroma colours will be different. In the retina colour sensitive receptors are 'triggered' to produce electro-chemical signals, which are sent to the brain to produce the sensation of colour.Many colour management-aware applications such as high-end RIPs and Adobe Photoshop contain an internal CMM. See Information on profiles and ICC White Papers If you are a developer and want to write software to do this you need to read the ICC profile specification to understand the format of the profile. A rendering intent defines how the gamut of colours which can be achieved on one media is modified when reproduced on a media with a different colour gamut. This takes account of the fact that the range (gamut) of colours on a print or display is often lower than the original ? Output profiles translate between the PCS and the output colour encoding.CMMs are also built in to the OS on the Mac (Color Sync) and Windows (ICM and WCS). If you want to write a CMM you are basically writing an interpolation procedure to enable you to 'join' two profiles of different size - though you will also need colour space conversions to cope with both PCS encodings and white point correction. Each profile contains three of these rendering intents and which should be used depends on the colour gamuts of the original and reproduction media. although for high gamut printing a colorimetric rendering (which attempts to produce an exact colour match) may be appropriate. Display profiles are commonly of the Matrix/TRC type, in which case they contain (in addition to the tags which all profiles are required to have, such as white point and copyright information): For full details of the structure, required tags and processing model, see the ICC profile specification . In the case of a printer profile, the output colour encoding might be monochrome, CMYK, RGB or n-colour, where n can be up to 16 (although in practice is rarely greater than 6 or 7). A devicelink profile converts data encoded in the colour space of one device to that of another device, and it is only good for those specific devices.