Total Area Coverage (TAC) – defined
Total area coverage or TAC, is the combined value of all CMYK inks for a particular area or object on a page. This value cannot exceed a specified amount, or ink may not transfer effectively and printed sheets may exhibit undesirable print quality characteristics such as blistering, picking or pages sticking together.
This specified amount is referred to as Total Area Coverage.
SWOP specifies TAC as:
SWOP (coated) #3 Sheet TAC = 310%
SWOP (coated) #5 Sheet TAC = 300%
UnCoated TAC = 260%
Total Area Coverage (TAC) – design
During the design phase of production, the designer must have an awareness of TAC and how to control it. With this awareness and a few settings changes in your desktop publishing applications, TAC will always be within tolerance for your intended print condition. Please contact us at technical support for information on the appropriate settings to use for your particular publication.
Total Area Coverage (TAC) – evaluation
Modern desktop publishing applications, such as those within the Adobe Creative Suite, have the ability to evaluate pages in regard to TAC.
The output preview or separations preview function within the application can be used to show you exactly where the TAC problem is on the
page. For help with identify TAC, please visit the support area of our website or contact us at technical support.
Total Area Coverage (TAC) – avoidances
The two most common situations that cause TAC levels to be out-of-tolerance are;
1) the use of Registration (100c, 100m, 100y, 100k) in the layout applications’ color palette, and 2) adjusting images incorrectly in Photoshop, after conversion to CMYK. Please contact us at technical support for specific information on the appropriate way to avoid these two problematic design issues.
Total Area Coverage (TAC) – tolerance / general guidelines
TAC (cumulative, square area) that exceeds the specified amount and represents 25% of the page or less will not typically cause any undesirable print quality issues. In contrast, however, TAC that exceeds the specified amount and represents more than 25% of the page is much more likely to exhibit undesirable print quality characteristics and should be avoided. Because of this, a second approval will be requested on all pages that fit this category during the final quality check of prepress production.