In my previous article, I talked about the importance of Print Standards. While I hope many of you got a lot out of it, there were probably others who were saying, “Standards? Standards? We don’t need no stinkin’ Standards.” You just need to print as big a color gamut as possible. Maybe you are doing wide format or dye sublimation and need the biggest possible gamut to match some wacky spot colors or customer samples. There are many inkjet devices with the proper setup can print a larger range of colors than litho devices. In those cases, printing to a press standard, especially a litho press standard, feels limiting. There are many reasons to print to press standards, but there are times you may need to go more “Wide Open.” Maybe you have tried that in the past with mixed results. Here are some things to think about when printing with “Wide Open Color.”
Ink Limits and Proper Prep are Important
One of the mistakes that many people make when trying to capture the full gamut of their machine is to set the ink limits wide open. That is almost never a good idea. Besides the obvious over-saturation problem of ink just dripping off the sheet, you can also get a problem known as “hooking.”
ColorGate Ink Limiting adjustment per CMYK channel- max black adjustment
Hooking occurs as you push the ink limits up, and at some point, the color per channel stops getting stronger and just starts changing hue or becoming weaker. Setting proper ink limits per channel is one of the trickier things to do as part of inkjet calibration, though extremely critical. Some RIPs, like EFI Fiery and ColorGate, have automated tools to help you set proper ink limits per channel. Many do not. Chromix Curve4 has an ink restriction function that can take the data from a P2P and help set ink restrictions.
If you are doing it by eye, make sure that you are familiar with a good test file that has single channel and Total Area Coverage (TAC)/Overprint section to help assess where to pull back.
Gray Balance is Key
Inkjet devices often have a natural cast to them. Our Epson proofer, right after linearization, will have a blue cast grayscale. A good output profile will take that into consideration, but by adding G7 or some other methodology into your calibration process, there may be times when you don’t even need an output profile. When the gray is properly balanced as part of the calibration, you can often print raw CMYK straight to a device and have the grays and flesh tones look natural while capturing the full gamut of the solid inks. That can really push the boundary of your color, especially on an inkjet device with a much larger gamut than litho.
Bypassing the RIP
Building on the point above, if you have managed your grays and managed your limits, you can often print through the RIP with color management turned off and really grab the full gamut of the device. This is where the power of a G7 or other gray balance methodology really shines. I was working with an associate from Europe who had never worked with gray balancing, just TVI or input/output ICC conversions. They were working on a printer with a 20% larger gamut than CRPC7 and wanted to be able to use full range of the gamut.
They were able to use the gray balanced printer to print raw CMYK with color management turned off and still get natural looking color with great saturation. Best of both worlds.
Summary
Standards are an important part of inkjet printing, especially if you have many devices that need to match each other or match a litho press. But sometimes it’s fun to think outside the gamut box and push the limits a little. I hope that some of these ideas will help you with Wide Open Color.
Remember though, the substrate and the print process will determine if working Wide Open is possible and testing through the complete print to finishing process is required.
Mike Todryk is a Color Technical Specialist for IWCO Direct. He has more than 20 years of printing industry experience and has specialized in Color Management for the last 18.