Hewlett-packard Development Company, L.P.

Alberto Such

Andres Gonzalez

Antonio Lain

Francisco Guerrero

Rodolfo Jodra

Andrew Mackenzie

Pau Soler

A system and method for color accuracy checking is discussed. In one embodiment, areas within a document are selected for color-checking. A confirmation is made that a second printing of the document has color values which deviate within tolerances from color values of a first printing of the document within each of the selected areas.

Color accuracy check

A portable document format (PDF) file includes a graphical object and a corresponding spot color space. The spot color space is represented by at least one spot color name and an alternate representation of the spot color with device-independent data.

Representations of spot colors

Conventional obstacles to entry and survival of small graphic-arts service providers are softened&#x2014;particularly for those businesses that operate as computerized 'ASP' enterprises involving wide-area networks&#x2014;by encouraging small operators to coexist effectively in use of a pivotal network-based service. One key mechanism promoting this capability is a system of optionally mutual links between the pivotal service and the ASPs. The service also counteracts a tendency in the industry to favor wastefully redundant vertical integration. On the other hand, the system also implements the prerogatives of an enterprise (such as a printing-broker ASP) that has an established customer, to closely channel the attention of that customer&#x2014;but subject, importantly, to being overruled by the customer. Ideally the system is carefully tuned to enable such customer action without unduly pressing the option upon the customer.

Open coventuring in a remote hardcopy proofing service, with preserved clientele, through interface sharing

While powerful in diffusion at one resolution to print photos at a finer resolution, the invention is not thus limited. It defines superpixels ('spels') for each desired colorimetric level, generates/receives image data, renders by finding levels for image positions, and prints an image using selected spels. One invention aspect finds a randomized value at each found level and uses the value to select the spel from plural ones for each level. Another aspect derives/maintains a randomized-value matrix; and maps a matrix location to an image position, to select a random value at that location and spel for that position. Another uses the value in common for all planes to select a spel for each plane at the found level&#x2014;compatible spels for different planes, to coordinate color placement in planes. Another controls defining/selecting for a blue-noise property of spels in aggregate. In another, spels defined for a level vary in value to yield nonintegral color quanta. Preferences: Rendering is 1D per color, plus a dummy dimension holding the value (a least-significant bit from rendering, in a color dimension but decorrelated from levels)&#x2014;and derives/maintains the matrix, derived/corrected for blue noise and including small interleaved 1D matrices tiled across and wrapped around the larger. Mapping uses values as pointers into dimensions of a spel table, and color-plane identification as a pointer into a third table dimension; it uses a common value in all planes to avoid drop-on-drop. Spels are Fourier-screened.

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Barcelona, Spain

Alberto Such