Why is flexo retouching so time consuming?
The main reason for flexo retouching is the inability of flexo processes to reproduce low dot
percentages. This problem has partially been tackled by improved technology in flexo processing. But on
the other hand, the same technology improvements also raise the expectation level of the print buyer.
Keeping up with these quality demands remains a big challenge for the flexo printer.
Recent improvements of dot gain compensation tools and color management have created the
expectation that all press problems can be solved with these techniques. Although tools like IntelliCurve
and Kaleidoscope are an absolute necessity for good flexo prepress, they don't solve all of the issues.
Even with the best IntelliCurve DGC curves, some unwanted artifacts and tonal jumps will remain.
Following picture shows the tonal response of a well-handled flexo print process. Too small dots were
professionally removed from the tonal range (using IntelliCurve) so that even the 1 % dot prints in a
stable way, avoiding dots breaking out thus spoiling the printed result. In most cases, this provides the
best result possible with DGC curves.
We clearly see the drawbacks of this approach:
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A visible tonal jump occurs in the highlights (the step from 0 to 1 % is very big)
•
Highlight contrast is seriously smaller than in offset (look at the difference between
1 and 10 %)
•
A substantial part of the highlights and midtones print darker than on offset (even 10 %
in flexo is still darker than in offset). Diminishing this effect is possible but at the cost of
further loss of contrast in the highlights. This is an equally difficult choice for all images.