Remember that in order to configure Maxtone, the minimum dot value must be known for each media and frequency.
As a review, the media representative starts by making a plate of a linear step test. The linear step test plate is examined on a light table, and ideally, printed. From this, the media representative can determine the minimum dot value.
Linear step test plate
Step wedge
Based on the print results, minimum dot is value determined to be nominal 5% (2% prints as scum dot, and 3% and 4% both show excessive gain over 5%).
Using the Kodak Dotsize_Calculator.xls (available on the flexo resource CD), you can calculate Maxtone size, based on the established minimum dot. In the above example, Maxtone will be calculated on a minimum dot of 5%. This is referred to as the nominal value, because it actually prints as 14%.
Maxtone calculator results
In this example, the calculator indicates that the 5% minimum dot at 133 line frequency has a 48-micron diameter (value is rounded to the nearest integer), and this value is entered in the Output Process Template, for the Maxtone Highlights value.
Process template Maxtone setting
Note: A value of 1 means no Maxtone is applied.
Another screen wedge is now output with Maxtone applied, and the results inspected in Copydot Toolkit or VPS.
Step test output with 48-micron stochastic
When the actual screened output is inspected, the results may not appear as expected. In the example, Maxtone was calculated to be equivalent to a 5% dot, and it would be expected that the 5% area would print as continuous AM dots. However, it is obvious that some dots are being removed from the 5% patch. The reason for this is that Maxtone is a mild second-order stochastic screen, which means that not all dots are exactly the same size. If viewed closely in the 1-bit TIFF, it is possible to see that some dots are larger than others. This dot size variation is done to improve the visual smoothness of Maxtone, and to aid in a smooth visual transition back to full AM. In fact, the AM dots are also varied slightly in size for a few grey levels after Maxtone has reverted back to full AM. Because some dots are made larger, this affects the tonal accuracy of the tone patches, and additional dots must be removed in transition areas to correct the tonal accuracy. For this reason, the 5% and 6% areas have a small number of dots removed, even though they are technically above the Maxtone break point.