articles/Printing/epsonstyluspro4900-page2
by Mike McNamee Published
THE NEW COLOUR AUDIT PROTOCOL
For the tests we have devised a new patch set which is more stringent than that formerly used in Paper Chase for colour auditing. We will take a considered view as we test the 4900 printer with more papers and perhaps adjust things at a later date. For the moment the patch set consists of the following:
1. A patch set of CMYK colours which follows the basic Fogra V3 protocols (which we also use for analysis of this set).
2. The Macbeth ColorChecker 24 swatch set
3. The Macbeth SG Swatch set which includes
- The CC 24 set
- An extended greyscale
- A range of skin tones
- An extended gamut set outside the range of the CC24 set
4. A set of near-neutral greys at 50% luminance arranged to be biased around the colour wheel (ie warm through to cool greys)
5. A new set of patches that we have called the HiGAM set (ie high gamut) these are selected from the Pantone GoE set and chosen to represent the outer margins of the gamut of the 4900, printing to gloss paper. They are intended to be challenging colours to reproduce!
For the initial analysis we have been using BabelColor's Patch Tool. This produces a huge spreadsheet of data from which we can cull the columns of interest. These are then fed into another 17 spreadsheets for graphical and statistical analysis of the data, split down into the various patch sets. The routine gives a comprehensive overview of a printer/paper/profile performance. The analysis is not for the faint-hearted but we are still not done, as we also measure Dmax and metamerism separately. Even so it remains important to make and look at 'real' prints and so this is also carried out (sometimes it will depend on the availability of paper).
The Fogra Patch set may be analysed using a Hoecker Plot. This separates the more general patch set performance from CMYK-specific, as applied to contract proofing - the HiGAM set, for example, is outside the Fogra 39 CMYK gamut in all areas except the strong red and magenta tones.
There are 21 days to get ready for The Society of Photographers Convention and Trade Show at The Novotel London West, Hammersmith ...
which starts on Wednesday 15th January 2025