Posts Tagged ‘Ricoh’

Example of Dithering

Dither is an intentionally applied form of noise used to randomize quantization error, preventing large-scale patterns such as color banding in images. Dithering has mainly been used for laser and inkjet printers. The individual laser dots are distributed as finely as possible in an orderly pattern, as you can see in the following example. Today, error diffusion is usually used

You will notice that these images become considerably darker when they are copied and are not really suited for further processing. The laser dots are not distributed well enough for this purpose, with a border line that is much too long appearing between the black and white elements.
 
Errors occur mainly at the borders of screen dots when film is copied to the printing plate and as a result of dot gain in print.

For that reason, screen dots should be placed as compactly as possible to minimize the size of the border line as much as possible.

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Create a new calibration set and higher density calibration target

In order to accurately calibrate the printer and achieve the largest available gamut, a new calibration set should be created. From the Fiery Calibrator choose “Manage…” on the Calibration Set pull down.

Fill out the Recommended Paper field with your media (EFI Laser Proof Paper XF130 Semimatt) and set the Halftone Mode pull down to “175 Line + Fine Text (1200dpi)”. Save the new calibration set with a descriptive name (“EFI XF130 175Line” for example), and choose “Fiery Pro C751- C651 Coated-Glossy v1RF” as the Output Profile. A new calibration set and output profile will be created, “Fiery ProC751-C651 Coated-Glossy v1RF (<new calibration set name>)”.

From CommandWorkstation : Device Center : Resources : Profiles : Output Profiles select the newly created profile, and click the Edit : Color Editor… button. Edit the % Density : D-Max values to the following: C = 1.75, M = 1.50, Y = 1.01, K = 1.80. Save the edited output profile with a descriptive name (“EFI FX130SM 175Line Edited Goal” for example).

Set the edited output profiles as the default in Command WorkStation : Device Center : Color Setup :Color Management : Expert Settings… : Output : Default output profile. Additionally, be sure that “Use media defined profiles if available” is turned off (unchecked).

Warm-up printer and calibrate

The printer should first be in a warmed-up state before proceeding with calibration and characterization. Print, measure, and apply, calibration for the newly created “EFI XF130 175Line” calibration set, utilizing the Fiery Calibrator. It is recommended to use the EFI Spectrometer ES-1000 method, choosing the 34 Sorted Patches page type. Printing 5 or more number of copies, selecting the last for measurement.

Measurements can be inspected in the Fiery Calibrator, by pressing the View… button, with the “Measurement vs. Target” option selected. If the D-max values of the target are not being achieved, it may be necessary to access “Adjustment Settings for Skilled Operators” through the Pro C751’s LCD control panel. Increasing the values in function #0203 “Adjust Maximum Image Density” or #0205 “Adjust Density Difference Across Feed Direction” can have a positive effect on the D-max printed (measured in the Calibrator). It is important to open and close the main panel door on the Pro C751 after adjustment, and to rerun Fiery calibration, checking that target densities have been achieved or exceeded.

Create an output profile

Utilizing Fiery Color Profiler Suite print profiling patches. Be sure in Calibration Setup that “Use current calibration” is selected. Instrument EFI ES-1000 or EFI ES-1000 with iO table can be used. The PageLayout : 1617 random (CGATS IT8.7/4) is recommended. Alternatively, the “Digital Press Form 1” can be printed with the following settings, and measured with an Eye-one Sis XL, utilizing ColorPort. Save the measurements in the CGATS format, conversion none.

Note: While Fiery Color Profiler Suite recognizes this measurement file format, the line with “DEVCALSTD XRGA” present in certain measurement file headers should be commented out or deleted. This allows the ColorPort measurement file to conform to the CGATS file specification and successfully read by Fiery Color Profiler Suite.

The following print properties are used to capture the printer’s calibrated state for creating an ICC profile. Any other settings should be set to the server’s factory defaults with the exception of media tray settings.

• Media : Media Type : Coated-Glossy

• Media : Media Weight : Paper Weight 4 (105.1 – 163.0 gsm)

• Color : Expert Settings : Color Input : CMYK/Grayscale : Bypass conversion

• Color : Expert Settings : Gray & Black Processing: Gray : CMYK : Off

• Color : Expert Settings : Gray & Black Processing : Black : Black text and graphics : Normal

• Color : Expert Settings : Output : “EFI XF130SM 175Line Edited Goal”

• Image: Halftone Mode : 175 Line + Fine Text (1200 dpi)

Once measurements are made, select “Generic CMYK setting” in Fiery Printer Profiler, and edit the black controls to have black start at 5% and black generation at 90%. Save the new output profile to the server or as a local file to import later. Associate newly created output profile with the previously created calibration set “EFI XF130 175Line” when importing into Command WorkStation. It is important that the edited calibration goal profile is set as default (“EFI FX130SM 175Line Edited Goal”) when you upload the new profile, for this is where the new profile will get it’s calibration goal.

Print the Digital Press Forms

Use the following set of print properties as a baseline for printing the press forms. There are individual exceptions for some of the press forms that will be noted.

• Media : Media Type : Coated-Glossy

• Media : Media Weight : Paper Weight 4 (105.1 – 163.0 gsm)

• Color : Expert Settings : Color Input : CMYK/Grayscale : GRACoL2006 Coated1 (EFI)

• Color : Expert Settings : Color Input : CMYK/Grayscale : Processing method : Full (Output GCR)

• Color : Expert Settings : Color Input : CMYK/Grayscale : Paper simulation : On

• Color : Expert Settings : Gray & Black Processing: Gray : CMYK : Off

• Color : Expert Settings : Gray & Black Processing : Black : Black text and graphics : Normal

• Color : Expert Settings : Output : [newly created output profile]

• Image: Halftone Mode : 175 Line + Fine Text (1200 dpi)