Bodoni Systems 4CX Technology is included in pressSIGN 8
The 4CX technology is revolutionary way of achieving a natural grey balance for both traditional litho & flexo presses as well as all digital printing devices. This is achieved by using adjustment curves applied in the same way as standard TVI curves.
4CX technology can be applied quickly and easily to the PDF workflow using pressSIGNAutoCurves. In the example below the file was printed on a digital device and the color bar in the center of the page was measured with pressSIGN and an i1. The target was ISOCoatedv2, but the operator could have chosen any CMYK ICC profile. The 4CX grey balance was then exported toAutoCurves. The file was then reprinted by dropping the PDF into the AutoCurves hot folder. It is quick and easy.
In order for 4CX to be available there must be an ICC profile associated with the target condition. All of the default standards in pressSIGN already have a profile included.
The source CMYK ICC profile describes the desired grey balance. The 4CX curves that are created adjust the grey balance so that your print has the same visual appearance as the original.
As only curves are used to make the adjustments there is no need for any complicated device link setups, solids and overprints are automatically preserved. Changes due to ink, paper or printer performance can a accommodated by just updating a set of 4CX curves.
Adjusting for print contrast
4CX technology accounts for difference in print contrast for both CMY and K. If the black of the device has a different L* value to that of the target then 4CX black adjustment curve takes this into account and scales the target L* value accordingly. If the print device produces a CMY solid different to that of the desired target then the grey balance is adjusted in response.
Using 4CX technology in litho & traditional print
Achieving a matching grey balance in solids and overprints with 4CX technology
In most cases we want to use the same grey balance of the target profile as that set for the solids and overprints. The solid ink and overprint colors are set in the target ICC profile and 4CX uses the same grey balance. The default ISO 12647-2 and GRACoL standards built into pressSIGN use this method. This method gives the best match for a press running to ISO 12647 -2 or GRACoL.
ExampleSolid/Overprint ICC Profile : ISOCoatedv2.icc (FOGRA 39)Grey Balance ICC Profile : ISOCoatedv2.icc (FOGRA 39)
Matching different solid and grey balance conditions with 4CX Technology
There are frequently cases where a different grey balance condition is required to that of the solids. You may, for example, the files are set up to ISO 12647-2 or GRACol 2006, but the job will be printed on uncoated stock. In this instance you would select the target ICC profile to reflect the achievable solids and overprints and select the grey balance target based on the way that the files have been delivered to the press.
- Solid/Overprint ICC Profile : PSO Uncoated.icc (FOGRA 47)
- Grey Balance ICC Profile : ISO Coatedv2.icc (FOGRA 39)
In this example where the files are created using ISO Coated v2 is that when leaving them in this color space and printing them on an uncoated stock with an uncoated press target they have a very poor appearance. The reason is that the grey balance and dot gain are very different between the files and the print target. 4CX adjusts the print contrast and grey balance to align the color balance of the files to the press without the need to pre-process the files to an uncoated standard before printing.
4CX Technology and digital printing devices
There are two ways of applying 4CX technology with digital devices such as laser printers, presses and large format inkjet. 4CX adjustment curves should only be applied to raw DEVICE DATA whatever existing color management workflow is used to convert files and calibrate the device. Raw device data is a measurement when it does not have any profiling or color management applied.
4CX technology applied to a profiled printer
4CX is a fast and powerful solution for returning any digital device to the same condition as when the original profile was made.
Output the pressSIGN 4CX color bar turning all color management off. Measure the control strip and export the adjustment curves to the RIP or Color Server.
Example:Color Server/RIP setup
Source ICC Profile : ISO Coated v2.icc (FOGRA 39)Destination ICC Profile : iGen4.icc
pressSIGN setupSolid / Overprint ICC : iGen4.icc
Grey Balance Profile : iGen4.icc
The 4CX curve adjustments should be applied in the RIP or Color Server after the conversion from the source to destination profile. In effect the 4CX curves essentially replace the calibration/re-linearization process.
This method will produce accurate results provided the destination profile is still appropriate for the device and substrate in use.
Correcting grey balance with 4CX without profile conversion
Make sure all color management is turned off in the RIP and print the 4CX color bar. Export the 4CX adjustments to the RIP (making sure the color management/color conversion is still turned off in the RIP) or a color server capable of applying curve adjustments, like inkWIZE AutoCurves.
- Solid / Overprint ICC Profile : iGen4.icc
- Grey Balance Profile : ISO Coatedv2.ICC (FOGRA 39)
The grey balance profile should be the same as the profile embedded in the files.
This method allows you to check in pressSIGN how far the solids and overprint values have changed since destination profile was created.
4CX technology without a target profile for solids and overprints
4CX curve adjustments from a measured sheet
If there is no defined target for the solid inks then use pressSIGN to generate a target.
Turn all color management off in the RIP and print one or more sheets with the 4CX color bar. Select this/these measurements in the 'Job Window' and hit 'Calculate' to average the readings. Go to preferences to add a new standard and from the drop down list and select 'Measured Sheet'. Now select the appropriate Grey Balance target based on the file setup. This will give you the best grey balance and the widest color gamut the device is capable of producing.
4CX technology - Exchanging colorants / Multi-Color printing
If you change colorants on the print device then normally you would need to make a whole new profile. 4CX creates a grey balance adjustment based on the actual colorants in use. This can be applied to jobs that originally contained 5 colors and can now be printed using only 4 colors, saving time and money.
- Original Job : CMYK + Red
- New Job : C Red YK
Here the red is replacing the Magenta. The original files are still CMYK. Using 4CX technology the grey balance would be corrected to account for the new colorant. A visual check can be made by exporting the 4CX curves as Adobe Curves and applying them in PhotoShop.
Use the same method for generating and applying the 4CX adjustments as from a measured sheet.