How to set Total Area Coverage? (newspapers and magazines)

[rdale]

I am working as a pre-press specialist for a large format print house, printing XL images with huge inkjets, photo-processes, etc. With these types of prints the TAC is typically handled at the RIP.

We are about to launch a new production department, that will be sending advertising print files (PDF/X1-a) to both newspapers (CMYK and Grayscale) and magazines (CMYK) all over the USA. From our research the SWOP standard TAC for newspapers is 240% for most papers, and around 300% for most magazines.

We do extensive color correction/color management for all files, however handling TAC is a new realm for us. The raster files we are receiving from the client are arriving (CMYK) with a TAC of around 340%. We need to adhere to SWOP standards according to our information from many various publications.

How do we set up the incoming rasters to meet theses ink limits, while still publishing files that are high quality, commercially acceptable and also meeting SWOP standards? What process would we use to meet these goals? Is it a color correction method, a color profile or some combination?

 

[meddington]

We do extensive color correction/color management for all files, however handling TAC is a new realm for us. The raster files we are receiving from the client are arriving (CMYK) with a TAC of around 340%. We need to adhere to SWOP standards according to our information from many various publications.

TAC is defined within an ICC profile. If you do extensive color management for all files (I'm assuming you mean repurposing files for a different print condition here) this could be as simple as selecting a 300 TAC profile for magazine files and 240 TAC for newsprint. I wouldn't recommend color correction.

 

[gordo]

The raster files we are receiving from the client are arriving (CMYK) with a TAC of around 340%. We need to adhere to SWOP standards according to our information from many various publications.
How do we set up the incoming rasters to meet theses ink limits, while still publishing files that are high quality, commercially acceptable and also meeting SWOP standards? What process would we use to meet these goals? Is it a color correction method, a color profile or some combination?

Interesting about the TAC of incoming files. Are you positive about that value? I ask because it's been reported from many sources over the years that the vast majority of RGB-->CMYK separations, whether for publication, newspaper, or commercial are done using PShop's default settings which provide a TAC of 300%.
To go from CMYK to CMYK and change the TAC, you'll likely need to do a transform using a device link profile.

best, gordo
my rambles here: Rambling Artists
my print blog here: Quality In Print

 

[Lukas Engqvist]

There are a number of colour servers that do exactly that, re seperate the files, dump in one folder pick up in the next minus the excess ink.

 

[rdale]

How to set TAC? (which icc profiles for SWOP?)

How to set TAC? (which icc profiles for SWOP?)

>Dear Meddington,
Thanks for the quick response!
>
> Do you know which icc profiles would work globally for most newspapers, or
> magazines, or will we need several profiles?
> Many of the newspapers require that no icc profile be embedded in the print
> pdf/x1‑a files containing rasters, which seems to present a paradox.
>
> Could we convert from SWOP to something like FOGRA29 (uncoated) and then
> convert back to SWOP? This seems to move the TAC down very close to 300%
> (for magazines).
>
> RogerD

 

[meddington]

Do you know which icc profiles would work globally for most newspapers, or
magazines, or will we need several profiles?

I don't work in the newsprint industry, but I would guess a profile from SNAP (Home Page) which is 240TAC
or perhaps the ECI/ISO profile based off of Fogra42, though the one from the ECI is at 260TAC I think.

any of the newspapers require that no icc profile be embedded in the print
> pdf/x1‑a files containing rasters, which seems to present a paradox.

A PDF/x1a file that references the output intent (rather than embeds) should be acceptable

ould we convert from SWOP to something like FOGRA29 (uncoated) and then
> convert back to SWOP? This seems to move the TAC down very close to 300%

Which SWOP profile are you using? The SWOP2006_Coated3v2.icc profile is already at 300%. Fogra29 is a data set rather than a profile. The Tac would be set at the time of profile creation. I would, as Gordo, recommend device links, particularly in the case of PDF conversion.

 

[JasonM]

Mike is close on the TAC for newsprints we use 235-240 TAC. The quality of the equipment it's run on will also make a difference for TAC (how well maintained it is). But I am guessing you already know that.

 

[PrePress Guru]

When i did stuff for news print, we used a tac of 200-245 depending on the publication. Some of them recommended even lower values (sad). I remember a friend of mine who used to work for them called the paper "bad toilet paper".

One thing we used to do to get the tac down when we didn't have any server apps or DL profiles is to convert it back to RGB then back to CMYK. It really didn't change the colors too much or mess with the files. It printed fine and no one complained but we new it wasn't optimal.
The things you have to do when your company is cheap!!

 

[mattbeals]

It would be very simple to set up a function in Callas pdfToolbox to apply a device link profile to go from SWOP to SNAP, GRACoL to SNAP, etc. There's actually a button that says "device link" so they make it really easy to do. If you want to be more selective about which device link you apply then that is also quite easy to do. It's possible to do this with PitStop Pro, just not as easily. I have a similar setup running at a commercial shop in New York who uses Callas pdfToolbox Server and one in Canada for a news paper printer.

 

[mdeleon]

If you are referring to tiff or jpeg images, check in photoshop if a profile is embedded. next, you may convert it to your preferred/target profile (edit>convert to profile using relative colorimetric as intent) then save. color appearance is visually maintained but the tac is changed according to your target.
btw, you have to verify from your client their working cmyk during the time they were converting to determine what working cmyk was targeted if in case there is no embedded profile so as to get the correct color conversion (your source color when you convert)

if this works then save your process as an action in photoshop to be able to let the computer work for you. best done through batch processing.