September 23, 2021

Precision vs. Accuracy

Every print device natively prints differently from one another even same make and model. When attempting to make multiple printing devices (digital, large format, flexography, sheetfed) match one another, it is imperative to ensure each device is consistent to itself, and that it is matching an industry reference print condition (which allows them to match one another). This requires both precision and accuracy.

Precision and accuracy are often confused and interchanged when talking about color control, but they are very different and need to be treated independently of one another. Precision should be determined before accuracy. Precision defines how repeatable a process is, not only within a page (intra-page variation) but also across multiple printed pages within the same job (inter-page variation or repeatability) and between different jobs (reproducibility). Precision is controlled through calibrating and linearizing the printing process, each process has it's own procedure and is very device specific. 

The ChromaChecker™ Print Inspector will calculate all levels of the precision of your device based on the measurement results from the control strips. Precision also defines how repeatable a process is over time, between jobs, between maintenance, to ensure a device is always coming back to it's known and consistent state within an allowable tolerance defined in delta E that you should have already defined by using the ChromaChecker™ E-Factor Exercise. This tolerance ensures the device is repeatable within a given amount of "color difference" which is determined to be acceptable by the owner of that device. Understand that paper or substrate that a device is printing on is considered the 5th color in four color printing and will greatly influence the color of the result. Often multiple substrates are used with the same device, which will influence the amount of color variation resulting from the print. Depending upon the desired tolerance required, you may need to profile groups of substrates that have similar color characteristics (within a given tolerance) to allow for the extreme differences that paper can have on your final color result. The ChromaChecker Print Inspector will calculate this for you based on your device/substrate characteristics.

 

LOW ACCURACY
LOW PRECISION
LOW ACCURACY
HIGH PRECISION
HIGH ACCURACY
LOW PRECISION
HIGH ACCURACY
HIGH PRECISION

 

Once the precision of a device/paper of a device is determined, then the ability to make that device/paper condition match an industry reference condition will be important. Matching a "reference" condition determines the "accuracy" of a device condition. By matching an industry reference condition, multiple devices within the same company can match one another, and multiple devices across the world can match one another within a given color tolerance, and be deemed acceptable (Pass) or unacceptable (Fail).  Accuracy is achieved by applying G7 curves, or ICC profiles in the workflow in order to adjust how each printing device needs to print in order to match the given reference condition.  ChromaChecker can create both the G7 Curve, and or the ICC Profile for the given print condition to help direct it to better match the desired reference condition.

The ChromaChecker™ Print Inspector will calculate which reference color space including your own imported color spaces are the closest match to your device/substrate characteristics for properly configuring your color conversion workflow, and how to assess the results. 

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