Spot color matching has always been a hot topic in printing. Luckily, VersaWorks® offers a number of tools to help users achieve accurate results print after print.
However, not all spot colors are the same, and depending on the tools you choose and how VersaWorks is configured, colors can be processed in ways that produce unexpected results. This week’s Friday Fare provides an overview of how spot colors are processed in VersaWorks.
Regular CMYK or RGB workflow
This is the process in which the raster images and non-spot color objects in your design file are converted to the printer’s CMYK color space through a series of color conversions. First, the objects in RGB or CMYK color are converted to L*a*b* color space – a color model that represents all visible colors using the input profiles specified in VersaWorks’ Color Management Properties. Colors are then converted from L*a*b* color to the printer color space according to the output profile. Be aware that if a spot color is not recognized by VersaWorks, it will also go through this same conversion process producing inaccurate results. This can occur if the spot color name in your design file doesn’t match up exactly with the name in the VersaWorks’ spot color library, or if VersaWorks is not set up to use the spot color conversion. To achieve the best results, it’s important to match the input profile settings in VersaWorks with the settings in your design application and select the correct output profile.
VersaWorks 4.8 or later now includes PANTONE libraries which are defined as L*a*b* color. This means that for PANTONE colors, the first color conversion step is unnecessary and colors are converted directly to the printer color space. Note that in this case, the input profiles are ignored because the color is already defined in the L*a*b* color. After that, the conversion happens in the same way as it would for any RGB or CMYK data using the output profile. Colors from DIC and TOYO color libraries as well as spot color libraries created in VersaWorks using the spectrophotometer work in the same way, as these libraries are defined as L*a*b* color. VersaWorks enables you to see if the color can be accurately reproduced by displaying the delta-E, which represents the difference between the spot color and the output color. In the commercial printing world, a delta-E of 3.0 or less is considered very good – very few people can see the difference.
Roland Color workflow
Roland Color is the most unique color matching system available. It’s somewhat of an oddball because it prints the color without any conversion, completely ignoring both input and output profiles. For example, the RVW-PR19K, which is defined as C=100%, M=0, Y=0, K=0, will be produced exactly as C=100%, M=0, Y=0, K=0 on the printer. This is also the most accurate system because VersaWorks allows you to print out a chart from which you’ll be selecting the color. As long as the chart is printed with the exact same settings as the one that will be used for production, the color selected will be reproduced with 100% accuracy. Although media profiles are ignored, VersaWorks uses calibration and ink limit information from the media profile, so it’s still important to select the correct profile. Choosing an incorrect media profile in VersaWorks may result in the printer laying down either too much or not enough ink, which can negatively affect print quality.
In summary, no matter what method you choose to use, it is always important to choose the right profile for the media. The color accuracy will be greatly affected by the quality of your profile and media, the integrity of the print heads and the calibration of your device, so make sure you keep your printer well maintained.
Group Product Manager – UV, Engraving and 3D Products