User manual HP 9850MFP

[. . . ] The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein. PostScript® is a trademark of Adobe Systems. [. . . ] This is done to incorporate the HP CMYK Plus effect during printing without the need to modify the document file. NOTE HP CMYK Plus works only on CMYK workflows, so it does not work on the PCL driver. 2 1 Overview of HP CMYK Plus 2 Benefits of HP CMYK Plus Using HP CMYK Plus, creative professionals can produce impressive portfolio prints and presentations using final CMYK files without clipped colors. Printers with HP CMYK Plus produce outstanding output with rich and vibrant colors that is perceptually consistent with press-printed documents in hue and lightness relationships. The output color looks just like offset four-color printing, only better. HP CMYK Plus is the ideal complement for digital devices with wider gamut than traditional offset. Print service providers can produce output from standard CMYK files (prepared for offset) that take full advantage of the gamut of the device at the first attempt, without manual intervention. This output is perceptibly consistent with offset output and the original RGB file. 3 4 2 Benefits of HP CMYK Plus 3 How HP CMYK Plus works When a digital printer receives a CMYK image without an attached color profile or other information, it typically assumes that the CMYK values are to be interpreted directly using its own colorants. HP CMYK Plus, on the other hand, takes into account the fact that most CMYK content is generated for offset presses, and applies a different approach to rendering untagged CMYK data on a particular digital printer. The HP CMYK Plus re-rendering process works as follows: 1 It first ensures that the black (K) channel is preserved so that a given K value in the source data is always replaced by the same black value in the destination (except for some rounding differences). Any source colors defined using K only (such as text, lines, or drop shadows) are also kept as K only in the destination. 2 The color appearance of the untagged source CMYK data is interpreted by applying a press ICC profile. The result at this stage would yield colors with the appearance of the source CMYK printed on a conventional offset press. Since the dynamic ranges of digital printers often differ from those of conventional presses, the dynamic range of the initial color values is transformed (by either compression or expansion) to fit that of the destination digital printer. The shapes of digital printer color gamuts also differ from those of conventional presses in terms of the levels of colorfulness that they can achieve at different hues and lightness levels. To make better use of the color gamut of a digital printer, the levels of colorfulness are also transformed. This results in more colorful digital prints than those obtained from an offset press, since the gamut of the digital printer is larger. This is done without distorting the appearance of neutral colors or familiar colors like skin tones. Throughout this re-rendering process, the hue of the source color remains unchanged, since this is the color attribute that can be most objectionable if changed in color reproduction. Keeping the hue as it would be on a press also means that HP CMYK Plus output is still consistent with press appearance. Destination CMY values are computed from the destination colors obtained above. The K amount is determined from the results of the first step and by using the ICC profile of the destination printer. [. . . ] This will leave wrong hue locations of the CMYK colorants. 3 8 3 How HP CMYK Plus works 4 How to use HP CMYK Plus NOTE HP CMYK Plus technology is available in the PostScript® driver. In the printer driver, click Properties. The Printing Preferences menu, comparable to the menu below, appears: In the window, click ColorWise, and the following window opens: 9 Click Expert Color, and the following window opens: In this window, use the pull-down CMYK Simulation Profile menu to select HP CMYK Plus. Click OK. 10 4 How to use HP CMYK Plus You can use HP CMYK Plus with any of the output profiles in the device. The first time that you select a new profile, the controller calculates the CMYK-CMYK device link and applies it. [. . . ]