[EN] Total Area Coverage (TAC)

What is it all about?

Depending on the printing conditions (printing method, paper and method of drying) the maximum area coverage is limited (area sum, maximum area coverage, TAC total area coverage).

The total area coverage is being calculated by the sum of the percentage of the color components of the primary colors C, M, Y, K. The minimal possible color assignment is 0% (C:0% + M:0% + Y:0% + K:0%), the highest 400% (C:100% + M:100% + Y:100% + K:100%).

The following chart shows calculated values for the deepest possible dark (CIE L*a*b* = 0;0;0) for 3 profile examples.

Profile

Cyan

Magenta

Yellow

Key

TACist

TACmax

ISOcoated_v2

88%

79%

65%

93%

325%

330%

ISOcoated_v2_300%

78%

68%

58%

94%

298%

300%

PSR_PLUS_V2_PT

93%

88%

93%

85%

359%

360%

These examples show that the same color (with the goal of the best possible result in printing) will generate different color values, depending on which profile is being used to convert it.

It also shows that through the conversion the range is almost being maxed out. The maximum necessary area coverage (TACmax) is being almost reached through the actual area coverage (TACist). Since the conversion results in some loss of performance which is accounted for mathematically, the DUON portal has added a tolerance level of +8% (on average +2% per color component).

How do I find the elements which have too much area coverage in my ad?

You can check this yourself if you have the full version of Adobe Acrobat.

Open you ad in Acrobat and choose the header Output Preview. You can reach the header at the top left hand side View> Tools > Print Produktion. Now a window opens Tools / Print Produktion which you can click on.

Now click on the box total area coverage und set the limit to 300% for offset and 380% for gravure printing. All areas that go beyond the limit will be displayed in neon green.

What can I do?

Look up your magazine in the DUON info area and see what profile is required. Make sure to differ between the profile for the inner pages and the cover pages.

Then convert all your data with the right profile.

Troubleshooting

One problem which often arises is the confusion between assign profile and convert to profile. Both commands sound identical but they are quite contrary:

In the command assign profile the percentage values saved within the picture are being interpreted as „device specific values“ and shown within this model. This command only makes sense if the source picture is unknown. If, for example, you don’t know what camera took the picture, you then have the option to assign the profile best suited. You get the result „the way it is supposed to look“.

The command convert to profile has a much higher importance because values of the source profile are being converted to a different device specific color space through a „conversion color space“ called profile connection space (e.g. CIE L*a*b*). If you convert a picture from the offset profile ISO_coated_v2 into the gravure profile PSR_LWC_PLUS_V2_PT it is necessary to change the device specific color space (CMYK) in order to maintain the same color impression ( CIE L*a*b*).

Should you use a command by mistake you should definitely convert it back to the original profile and then do a conversion.

 

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