Managing the Spectrum

It’s a common challenge: What’s seen on the computer doesn’t always translate to the actual print—at least not when it comes to matching colors.

To shed some knowledge on this, Sign Builder Illustrated connected with Jeff Burton, the digital printing analyst at the Specialty Graphic Imaging Association (SGIA). Since 1998, Burton has been consulting on digital imaging production, computer, and workflow issues, as well as digital equipment/vendor recommendations. He has also developed webinars and classroom curriculum in color management.

What advice do you have for sign companies and print providers to ensure color management in the printing process?

Jeff Burton: My advice falls into two categories: First keep learning, understand the theories of color management, and comprehend the jargon used and the use of color instruments in a particular color workflow. It’s also vitally important to keep up with what new color software, hardware solutions, and standards are available that can enable your business to either raise profitability or rise above the competition.

The other category of advice I have has more to do with the practical application of a color-managed workflow. Having a full understanding of the process is one of the key elements, but one also needs to know how to set up the Raster Image Processor (RIP) so that the color-managed workflow can succeed. If the RIP manufacturer offers advanced workshops, webinars, or classes, take them.

Do you have any tips that you can provide when it comes to saving and manipulating these files before output?

Manipulating customer files to get a better color match is a very common occurrence. It does cost a business time that’s not usually billed for unfortunately.

Another issue in doing this concerns how different operators amend the files for output. Are they all doing the same things?

The job sheet needs to reflect who did what to the file to get correct color. If you can standardize the production workflows in your business, your time spent per job will decrease accordingly and quality color becomes more repeatable.

What mistakes can one make when it comes to color reproduction through inkjet printing, and how can one prevent them?

There are so many: Incorrect profile used, nozzle outages, color space, wrong media utilized, using RIP settings inadvertently left over from the last job, lack of pre-flighting to address basic issues before output, etc.

Prevention comes down to a basic checklist for the preparation of the file, setup of the RIP, and the printer settings for the specific job output.

But there are bigger issues beyond the procedural ones that prevent digital companies from achieving color consistency.

What complicates a color-managed workflow is to have multiple RIPs from different manufacturers driving different output devices. Although each individual printer is color-managed, there’s no unified control station for color.

A better approach is to have a singular RIP driving the lion’s share of the output devices. But that scenario happens in fewer places than you’d expect.

After minimizing the number of RIPs in a business, setting proper ink limits is the next critical step of a color-managed workflow. Improper ink limit settings (especially for solvent-based inkjet) cause myriad issues ranging from poor color densities to costly ink consumption issues. Because this step comes before the actual media color profiling, it’s also the key to getting the best color possible from a particular media configuration.

Another item to examine is the oft-ignored input profiles at the RIP level. Are they set for smaller color gamuts than the files you’re sending? An example of this would be the presets of sRGB and Standard of Web Offset Printing (SWOP) versus the larger color spaces of AdobeRGB and General Requirements for Applications in Commercial Offset Lithography (GRACoL).

Again it all depends on your color workflow and the types of files that get printed. But paying attention to the details can allow one to optimize the color output from any device.

ColorManage2

What advice do you have for making colors match the proof when it comes to inkjet output?

Matching an inkjet print to a proof is a common issue only because some clients continue to supply proofs without specifying the reference print condition. By reference print condition, I mean was it a proof made to guidelines such as SWOP target values? Or to GRACoL? Or to no target values at all?

Most output devices can be calibrated to print in the same reference print condition as the proof. But when no color reference is given, the match must be made visually, which uses lots of labor and materials.

Making colors match without a standard happens so much that it’s almost the norm. There are two basic paths I see production personnel using:

One path entails printing out a color chart on the same media that the final will be produced on and walking the color chip or print up to the chart. The chart’s color value is recorded and replaced in the file for output. Very often, the time spent doing this is absorbed by the business.

Path two has designs using PANTONE® colors that are designated as spot colors. When so designated, the spot color library in the RIP can provide a closer color match, depending on the media configuration in use.

If the spot color needs adjusting, a color ring around (sample of printed colors that surround a target color) can be generated sometimes by the RIP and the value of the spot color amended for future use. Doing this saves time, so that when that color is referenced in the future, it’s ready for printing immediately—no reverse engineering is necessary.

Can you provide any guidance on printers or printing technology that would be important for sign shops to consider?

For the sign shop, some of the overlooked places where color issues hide are in three major areas.

The first is in the media or substrate itself. We call this the “white point” of the material. Is it actually white? Or does it contain a color cast that changes the image’s overall look? Some plastics can be bluish white, while others can be neutral or have a warm hue.

Laminates are another area, as they’re often thought to be optically clear. If you’ve profiled a critical color, printed it, and then laminated it only to see a color shift occur, you’ll know what I’m talking about here. Laminates will typically have a shift towards yellow, depending on the thickness and amount of UV inhibitors in the product.

Finally consider the light source that the final product is viewed under. The only standard for viewing conditions currently is D50 as a graphic standard viewing condition—not shop light, not daylight, and not desk lamp. Standardized viewing conditions are very important when discussing color and images with multiple service providers or customers in diverse locations.

By Lori Shridhare

Photos (top to bottom): Dave Forrest, Shutterstock


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