Understanding and Using Color

This document describes how the HP Color LaserJet 3500 and 3700 series printers provide great color printing. This document also describes ways to produce the best possible color prints. The following topics are covered:

Using color

Managing color

Matching colors

Using color
The HP Color LaserJet 3500 and 3700 series printers offer great color printing as soon as the printer is set up. They provide a combination of automatic color features to generate excellent color results for the general office user. Also, the HP Color LaserJet 3700 series printer provides sophisticated tools for the professional who is experienced with using color.

The printer provides carefully designed and tested color tables to provide smooth, accurate color rendition of all printable colors.

HP ImageREt 2400

HP ImageREt 2400 is a technology that provides the best color print quality without having to change printer driver settings or make trade-offs between print quality, performance, and memory. ImageREt 2400 produces photorealistic images.

HP ImageREt 2400 has been improved for this printer. The improvements offer trapping technologies, even greater control over dot placement, and more precise control of toner quality in a dot. These new technologies, coupled with HP's multilevel printing process, result in a 600 x 600 dpi printer that provides 2400 dpi color laser-class quality with millions of smooth colors.

Paper selection

For the best color and image quality it is important to select the appropriate paper type from the software printer menu or from the printer control panel. Click here to view or print the HP LaserJet Printer Family Print Media Guide .

Color options (available for the HP Color LaserJet 3700 series printer)

Color options automatically enable optimal color output for diverse types of documents.

Color options use object tagging, which allows optimal color and halftone settings to be used for different objects (text, graphics, and photos) on a page. The printer driver determines which objects are used on a page and uses halftone and color settings that provide the best print quality for each object. Object tagging, combined with optimized default settings, produces great color out of the box.

In the Windows environment, the Automatic and Manual color options are on the Color tab in the printer driver.

Standard red-green-blue (sRGB)

Standard red-green-blue (sRGB) is a world-wide color standard originally developed by HP and Microsoft as a common color language for monitors, input devices (scanners and digital cameras), and output devices (printers and plotters). It is the default color space used for HP products, Microsoft operating systems, the World Wide Web, and most office software sold today. The sRGB standard is representative of the typical Windows PC monitor today and the convergence standard for high-definition television.

NOTE: Factors such as the type of monitor and the room's lighting can affect the appearance of colors on a screen. For more information, click here to see "Matching colors" below .

The latest versions of Adobe PhotoShop, CorelDRAW, Microsoft Office, and many other applications use sRGB to communicate color. Most importantly, as the default color space in Microsoft operating systems, sRGB has gained broad adoption as a means to exchange color information between applications and devices using a common definition that ensures typical users will experience greatly improved color matching. The sRGB standard improves the ability to match colors between the printer, the PC monitor, and other input devices (scanners and digital cameras) automatically, without the need to become a color expert.

Printing in four-colors, CMYK (available for the HP Color LaserJet 3700 series printer)

Cyan, magenta, yellow, and black (CMYK) are the inks used by a printing press. The process is often called four-color printing. CMYK data files are typically used by and originate from graphic arts (printing and publishing) environments. The printer will accept CMYK colors through the PS printer driver. The printer color-rendering of CMYK is designed to provide rich, saturated colors for text and graphics.

CMYK ink set emulation (PostScript only)

The printer’s color rendering of CMYK can be made to emulate several standard Offset Press ink sets.

Default - This selection is good for general purpose rendering of CMYK data. It is designed to render photographs well, while at the same time providing rich saturated colors for text and graphics.

Specifications for Web Offset Publications (SWOP) - Common ink standard in the U.S. and other locations.

Euroscale - Common ink standard in Europe and other locations.

Dainippon Ink and Chemical (DIC) - Common ink standard in Japan and other locations.

Device - Emulation is turned off. To render photographs properly with this selection, images require color management in the application or operating system.

Use the SWOP or EURO emulation of CMYK inks to achieve the best match of PANTONE four-color (4C) process colors from PANTONE-certified applications, depending on the color palette sample book used.

Managing color

Setting color options to Automatic will typically produce the best possible print quality for color documents. However, there may be cases when it is desired to print a color document in grayscale (black and white) or to change one of the printer's color options. The following list and sections describe how to print in grayscale for Windows and Macintosh.

Windows: Select the Print in Grayscale option in the software application or change the color options using settings found on the Color tab in the printer driver.

Macintosh: Select the Print in Grayscale option in the software application or change the color options using the Color Matching pop-up menu in the Print dialog box.

Print in Grayscale

Selecting the Print in Grayscale option from the printer driver prints a document in black and white. This option is useful for printing color documents that will be photocopied or faxed.

When Print in Grayscale is selected, the printer goes into monochrome mode (regardless of what the COLOR/BLACK MIX setting is). This mode will reduce wear on the color print cartridges.

Automatic or manual color adjustment

The Automatic color adjustment option optimizes the neutral gray color treatment, halftones, and edge enhancements used for each element in a document. For more information, see the printer driver online Help.

NOTE: Automatic is the default setting and is recommended for printing all color documents.

The Manual color adjustment option allows the neutral gray color treatment, halftones, and edge enhancements for text, graphics, and photographs, to be adjusted. To access the Manual color options, from the Color tab, click Manual and then click Settings.

Manual color options

Manual color adjustment allows the user to adjust the Color (or Color Map) and Halftoning options individually for text, graphics, and photographs.

NOTE: Some applications convert text or graphics to raster images. In these cases, the Photograph settings will also control text and graphics.

Halftone options affect the resolution and clarity of color output. It is possible to select halftone settings for text, graphics, and photographs independently. The two halftone options are Smooth and Detail.

For the HP Color LaserJet 3700 series printer, the following options are available for the Halftone setting:
Smooth - provides better results for large, solid-filled print areas. It also enhances photographs by smoothing out fine color gradations. Choose this option when uniform and smooth area fills are top priority.

Detail - is useful for text and graphics that require sharp distinctions among lines or colors, or images that contain a pattern or a high level of detail. Choose this option when sharp edges and details are top priority.

The Neutral Grays setting determines the method used for creating gray colors used in text, graphics, and photographs.

For the HP Color LaserJet 3700 series printer, the following options are available for the Neutral Grays setting:
Black Only - generates neutral colors (grays and black) using only black toner. This guarantees neutral colors without a color cast.

4-Color - generates neutral colors (grays and black) by combining all four toner colors. This method produces smoother gradients and transitions to non-neutral colors, and it produces the darkest black.

The Edge Control (for the HP Color LaserJet 3500 series printer) setting determines how edges are rendered. Edge control has two components: adaptive halftoning and trapping. Adaptive halftoning increases edge sharpness. Trapping reduces the effect of color plane misregistration by overlapping the edges of adjacent objects slightly.

For the HP Color LaserJet 3700 series printer, the following levels of edge control are available:

Maximum - is the most aggressive trapping setting. Adaptive halftoning is on for this setting.

Normal - is the default trapping setting. Trapping is at a medium level and adaptive halftoning is on.

Light - sets trapping at a minimal level, and adaptive halftoning is on.

Off - turns off both trapping and adaptive halftoning.

For the HP Color LaserJet 3500 series printer, the following levels are available:
Maximum - is the most aggressive trapping setting.

Normal - sets the trapping at a medium level.

Light - sets trapping at a minimal level.

Off - is the default trapping setting. Trapping is turned off.

For the HP Color LaserJet 3700 series printer, the following values are available for the RGB Color settings:
Default - instructs the printer to interpret RGB color as sRGB. The sRGB standard is the accepted standard of Microsoft and the World Wide Web Consortium, for more information click here and visit http://www.w3.org.

Vivid - instructs the printer to increase the color saturation in the midtones. Less colorful objects are rendered more colorfully. This value is recommended for printing business graphics.

Device - instructs the printer to print RGB data in raw device mode. To render photographs properly with this selection, it is necessary to manage image color in the application or operating system.

Matching colors
The process of matching printer output color to a computer screen is quite complex because printers and computer monitors use different methods of producing color. Monitors display colors by light pixels using an RGB (red, green, blue) color process, but printers print colors using a CMYK (cyan, magenta, yellow, and black) process.

Several factors can influence a user's ability to match printed colors to those on a monitor. These factors include:

Print media

Printer colorants (inks or toners for example)

Printing process (inkjet, press, or laser technology for example)

Overhead lighting

Personal differences in perception of color

Software applications

Printer drivers

PC operating system

Monitors

Video cards and drivers

Operating environment (humidity for example)

Keep the above factors in mind when colors on a screen do not perfectly match printed colors.

Color Palette Sample book color matching (available for the HP Color LaserJet 3700 series printer)

The process for matching printer output to preprinted color palette sample books and standard color references is complex. In general, it is possible to obtain a reasonably good match to a color palette sample book if the inks used to create the color palette sample book are cyan, magenta, yellow, and black. These are usually referred to as process color palette sample books.

Some color palette sample books are created from spot colors. Spot colors are specially created colorants. Many of these spot colors are outside of the gamut (color range) of the printer. Most spot color sample books have companion process sample books that provide CMYK approximations to the spot color.

Most process color palette sample books will have a note on what process standards were used to print the color palette sample book. In most cases, they will be SWOP, EURO, or DIC. To get optimal color matching to the process color palette sample book, select the corresponding ink emulation from the printer menu. If the process standard cannot be identified, use SWOP ink emulation.

For best matching of PANTONE four-color (4C) process colors, use the SWOP or EURO emulation for CMYK inks in the HP Color LaserJet 3700 PostScript emulation driver when printing from PANTONE -certified applications.