Darrin Jenkins wrote:
Dear list
I have a job coming up that involves the copying of a painting for a client's Christmas card. The image will be shot digital and supplied as an Adobe 98 RGB file. The problem is the painting consists of blocks of bright colours, most of which will not reproduce faithfully in CMYK. I have suggested to the printer to use more inks and he said he would try Hexachrome 6 colour printing.
We are in the midst of testing hexachrome and stochastic screening for a brochure we are currently producing (my firm does both the graphic design and photography). The products in the brochure include several that are made from flourescent vinyls. In the past, these colors have been impossible to hit accurately with traditional four-color printing.
The printer has suggested using hexachrome, and has even made their presses available for press proofing the images prior to settling on a method of separating. We've seen press proofs on three variations - using traditional CMYK inks, standard screening at 175 line, hexachrome CMYK only with stochastic screening, and true hexachrome CMYKOG with stochastic screening.
The results have been interesting. As you would expect, yellows, oranges and greens reproduce beautifully, the closest we've seen in nearly twenty years of designing for this client. The more 'normal' hues - variations of blues in particular, are a little harder to hit accurately. They seem a lot more saturated than traditional CMYK. A lot like the difference between Kodak and Velvia transparency films.
I asked him about the colour management / profiles for Hexachrome and he replied that profile tagged files don't work for Hexachrome, and he will have to do trial and error wet proof tests to get the optimum result.
In our case, while we would normally produce the CMYK conversions in house, the printer is handling that through their own prepress department. All digital images are supplied as RGB originals with aim prints, some images that have been picked up from previous pieces can only be supplied as CMYK files.
We are going through a lot of loose proofs to get color accurate.
I understand that Kodak is just now releasing a new proofer that will accurately proof Hexachrome files. This has been the biggest problem with the technology to date. No accurate proofs.
Does anyone know if this is normal for Hexachrome or if the is a best / better way to print accurately the colours? There is a 70,000 print run so rule out my 1290!
From what I can see in the press proofs we've reviewed so far, the Hexachrome files are reproducing the vibrant colors extremely well. We are liucky to be using a printer who is willing to press proof this job - it's not that common these days.
Printing is always a bit of a cdrapshoot - there's always a compromise to be made in the process somewhere, the trick is to get everyone involved to understand where the compromises can be acceptably made.
Good luck
-- Jeff Smith
Smith/Walker Design and Photography
P. O. Box 58630 Seattle, WA 98138 ph: 206-575-3233 fx: 206-575-3960
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