Image Printing to Commercial Printing Machine (1)

Photoshop allows you to prepare image files for printing on commercial printers of different types (such as lithography, digital printing, and gravure printing).

Prepare the image for printing

In general, your workflow depends on the capabilities of the preprinting equipment. Before starting the commercial printing workflow, you need to contact the person who will output the file to understand what they want you to do. For example, they may not want you to switch to CMYK mode at any time because they have specific settings that need to be used. Here are some possible scenarios for preparing image files to achieve the desired printing results:

Always work in RGB mode and ensure that the image file is embedded using the RGB workspace profile. If your printer or pre-printer uses a color management system, they should be able to use your file's profile to accurately convert to CMYK mode to generate film and plates.

Before you finish the image editing, work in RGB mode. Then, convert the image to CMYK mode and do any other color and hue adjustments, especially check the highlight and shadow areas of the image. Use the Levels, Curves, or Hue/Saturation commands to correct. The magnitude of these adjustments should be very small. Then, send the CMYK file to a professional printer.
Place RGB or CMYK images in Adobe InDesign, Adobe Illustrator, or Adobe PageMaker. In general, most images printed on commercial printers are not printed directly from Photoshop, but are printed from page layout programs (such as Adobe InDesign) or print smart programs (such as Adobe Illustrator). For more information on importing Photoshop files into Adobe InDesign or Adobe Illustrator, see Adobe InDesign Help or Adobe Illustrator Help.

Here are a few questions to keep in mind when dealing with images intended for commercial printing:

If you know the printer's printing characteristics, you can specify highlight and shadow output to preserve some details. For more information on setting the hue and color output of an image, see Color and hue adjustments.
If you print an image on a desktop printer to preview the appearance of the final printed image, keep in mind that there are differences between desktop printers and commercial printers. You may find that the final image does not look very similar. Professional color proofs provide a more accurate preview of the final printed image.

If you have a profile from a print shop, you can select it using the Proof Settings command and use the Proof Color command to view the soft proof. This method will provide a preview of the final printed image on your monitor. For more information on soft proofs, see Electronic Proofing Colors.


Specify preprint options

Photoshop's Print Preview command includes the option to prepare the image for output to an imagesetter or plater. These options include specifying page marks, halftone attributes, color channels as individual pages, and print encoding methods. Typically, these output options should only be specified by a pre-printing professional or a person who has extensive knowledge of commercial printing processes.

Set output options

If you want to prepare an image for commercial printing directly from Photoshop, you can use the Print Preview command to select and preview various page logos and other output options.

Page mark A. Gradient background bar B. Label C. Registration mark D. Continuous color bar E. Corner cut mark F. Center cut mark G. Description H. Star target setting output options:

Choose File > Print Preview.
Select "Show other options" and choose "Output" from the pop-up menu.
Note: The options not supported by the specified printer are invalid.

Set one or more of the following options:
background

Allows you to select the background color printed outside the image area on the page. For example, black or colored backgrounds may be ideal for slides printed to film recorders. To use this option, click Background and select a color from the Color Picker dialog box. This is just a print option; it does not affect the image itself.

Expanding

Allows you to print a black border around the image. Type a number and select a unit value to specify the border width.

Bleeding

Allows you to print trim marks within the image instead of outside the image. Use this option when you want to crop an image within a graphic. Type a number and select a unit value to specify the width of the bleeding.

Screen

Allows you to set the screen frequency and dot shape for each screen used during printing. (See Selecting Halftone Screen Properties.)

transfer

Enables you to adjust the transfer function that is traditionally used to compensate for dot correction or dot loss that can occur when the image is transferred to film. This option is only recognized when printing directly from Photoshop or when storing a file in EPS format and printing it to a Postscript printer. In general, it is best to adjust the dot correction using the settings in the CMYK Settings dialog box. However, the transfer function is very useful when compensating for output devices that are not properly calibrated. (See Using the transfer function to compensate for dot corrections in film.)

Interpolation

Reduces the jagged appearance of low-resolution images by automatically resampling upwards when printing. However, resampling may reduce the sharpness of the image quality. (See About Resampling.) Some Postscript Level 2 (or higher) printers have interpolation capabilities. If the printer does not have interpolation capabilities, this option is not valid.

Calibration bar

Prints 11 shades of gray, a transition from 0 to 100% in 10% increments. For CMYK separations, a gradient bar is printed on the left side of each CMY plate, and a continuous bar is printed on the right side.

Note: Calibration bars, registration marks, crop marks, and labels are only printed when the size of the paper is larger than the size of the printed image.

Registration mark

Print registration marks (including bullseye and star targets) on the image. These tags are mainly used to align color separations.

Corner cut mark

Print crop marks at the point where you want to crop the page. You can print crop marks on corners.

Centering cut mark

Print crop marks at the point where you want to crop the page. The trim marks can be printed in the center of each side.

Instructions

Print any description text (up to approximately 300 characters) entered in the File Info dialog box. (See Adding file information (Photoshop).) Description text is always printed in a 9-point Helvetica regular font.

label

Print the file name above the image.

The medicine film is facing down

Make the text readable when the film is down (ie, the film or photo-sensitive layer facing away from you). Under normal circumstances, the image printed on the paper is printed upward with the film facing up, and the photosensitive layer is readable when facing you. The image printed on the film is usually printed with the film facing down.

negative

Prints an inverted version of the entire output (including all masks and any background colors). Unlike the Invert command in the Image menu, the Negative option converts the output, not the image on the screen, to a negative film. Although positive film is common in many countries, you may need negative film if you print directly to film. Check with the printer to determine which method is needed.

To determine the orientation of the film, check the film under bright light after rinsing the film. The dark side is the medicinal film, and the bright side is the base surface. Check with the printer to see if the positive film film is facing up, the negative film is facing up, the positive film is down, or the negative film is down.