Printing on the HP Indigo Press

To better understand what printing solution will best suit your need, below are some basic guidelines you need to know when submitting a digital printing job for the HP Indigo press.

What is "Digital" Printing?

The printed image is created directly from digital data – in other words, pages, text and images created with electronic layout or desktop publishing programs.  Unlike conventional printing processes, there are no intermediate pre-press processes between the digital document file and the final print. No film, no imagesetters, no plates, no platesetters, no photo-chemicals and NO WASTE. There is also no press make-ready: no plate mounting, no registration adjustments, and no ink keys. Indigo’s process is fully digital from creation to printing.

Page Dimension

Picture
Maximum paper size that can be fed on the Indigo is 12 x18 inches. Maximum image area is 11 5⁄8 x 17 3⁄16 (11.625 in x 17.1875 in) including crop marks. This allows for a 1⁄8 inch (.0625 in) bleed on an 11 x 17 page with cropmarks.

Pre-Flighting

We only include BASIC pre-flighting with each Indigo job submitted.  Basic pre-flighting includes the following:
  • Check that non-supported fonts are supplied to us
  • Check that all imported graphics and images are embedded or supplied to us
  • Check that all imported graphics and images are in the right format, resolution and color mode
Basic file pre-flighting does not include trapping, knockouts, overprints, layout, alignment, or embedded graphics.  We can do these services for an additional fee. 

Supported Applications

e support native files from the following applications:
  • InDesign
  • Illustrator
  • Photoshop
  • QuarkXPress
  • Acrobat
Files created from applications other than the above can be given to us already imaged in a high resolution PDF file (at least 300dpi resolution).

File Format

All graphics and images must be in CMYK.  Duotones created with PMS colors MUST be converted to CMYK and saved as a TIFF or EPS. The Indigo does not support DCS (desktop color separation). Please note that BMP and GIF image formats do not work well with the HP Indigo.

Fonts

We support the entire Adobe font library for Mac and Windows.  Any other fonts used should be supplied to us.  We recommend that Adobe Type fonts be used for all variable data jobs.

Screen Tints and Highlight Area

As in all printing processes, reproduction of light screen tint values and highlight areas is process-critical. Screen values for highlight areas should not be below 6% for cyan, and 5% for magenta, yellow or black.

Trapping and Registration

Because the sheet remains stationary on a rotating drum while each color is transferred, the Indigo has near-perfect image registration. Consequently, the need for trapping is almost non-existent. Files are processed as composite Postscript only. Composite Postscript doesnot consider separate colors as independent, and therefore disregards information used to create traps. Automatic trapping in programs such as PageMaker, QuarkXPress and Illustrator will be ignored by the Indigo.
 
To obtain a denser black when using 100% black that overlays an image or underlying color, use the following formula to create a rich black color: 40% cyan, 40% magenta, 30% yellow and 100% black.

Image Resolution/Color

The Indigo's default line screen output is 144 lpi (lines per inch) Images should be saved at 300dpi.  Lineart images should be scanned at a minimum of 800 dpi for best results.

The Indigo uses the CMYK color model  so accurate color output can only be achieved on the HP Indigo in CMYK color space.  All spot colors and pantone colors are converted to CMYK process when printed.

Background Color

In general, small areas of solid color reproduce better than large areas.  Large areas of flat background color are currently not recommended since they may appear mottled. Cyan and black are also susceptible to mottling in the 40% to 80% tint range. To avoid this mottled effect, create a TIFF image in Photoshop using the Add Noise filter. Set a value
between 5 and 15, and check Monochromatic to avoid introducing randomly colored pixels.

Bleeds and Crop Marks

When preparing a file with full bleed printing, make sure to put in an least 1/8 inch (0.125 in) bleed around the artwork.  Do not put any crop marks or printer marks when saving the file.

Blends and Gradients

Subtle blends and gradients tend to show some banding. To avoid this effect create the blend or gradient in Photoshop using the Add Noise filter and save as a TIFF or EPS file. Set a value between 5 and 15, and check Monochromatic to avoid introducing randomly colored pixels. Optimal results are achieved shorter blends and
gradients with a tonal value change of 50% or less.

Imposition

Chroma will impose your job to maximize the sheet size and allow for better registration of the front and back.  Even if we take care of imposing your job, you still need to design in any bleeds necessary.  When designing your artwork consider how you can make best use of the 12x18 sheet so you can save on printing costs. (of course the more you can put on a page, the less cost per piece!)
Download a PDF document of the Digital Printing guide.

Duplex (2-sided) Printing

A slight variation in image positioning can occur from sheet to sheet.  Allow at least 1/16 inch variation from front to back.
If you are still unsure or have more questions, please feel free to contact us.
We would love to hear from  you!