Expert: Glen Demers - 2/19/2009

Question
QUESTION: I am a Graphic Designer working in a pre-press environment. We are
launching a new production area sending ads to many newspapers and
magazines. We have found that TAC for newsprint is 240% and 300% for
magazines using SWOP specs. We are new to managing TAC, as we are a large
format printer using large inkjets. Do we manage TAC through Photoshop, or
with icc profiling (SWOP, FOGRA, SNAP, GRACOL-profiles we are comparing)?
A paradox-many newspapers ask that no icc profile be embedded in rasters-
do they add their own profile to our PDF/x1-a to control dot gain and TAC?

ANSWER: Hi Roger,

The easiest way to manage TAC is through Photoshop. It is set in the color settings.
You may wish to set up 2 Photoshop profiles for working with images - a standard SWOP profile for magazine work and a newsprint profile with lower (240%) TAC. You can use the SWOP color space as your default CMYK space and convert images to the newsprint profile when you need to. When you convert an image to the newsprint profile, rather than assign a profile, the look of the image will remain virtually unchanged but the readings in the shadow area will change. Converted images should be renamed to let you know they have a lower TAC.
There is no need to worry about dot gain - this is taken care of in the plate settings at the printer. As long as images are converted to the target profile in Photoshop and you don't build any rich blacks or dark colors that violate the TAC limits in your layout or drawing software, you can produce pdf's that will look good on screen and reproduce accurately in newsprint or magazines.
If you are running newspaper ads with the same publisher you may also want to check with their pre-press department as they may have suggestions for GCR/UCR settings in your newsprint profile that will help reduce total ink coverage and keep your pictures looking sharp and bright.

Hope this helps,
Glen Demers
Adobe Certified Expert, Photoshop 7
Prepress Technician, Best Printing Online
www.bestprintingonline.com

For more Photoshop tips please visit our help pages here


---------- FOLLOW-UP ----------

QUESTION: Many newspapers are asking that no icc profile be embedded in PDFs
containing rasters. How do we proceed with them? Are they applying their
own profile in pre-press? Or could they be using a pre-flight system such as
ASURA to manage color, dot gain, GCR/UCR settings?

Thanks for the help!
RogerD

Answer
Hi Roger,

First, forget UCR/GCR - Adobe recommends using their profiles and not messing with custom settings.

When you have raster images destined for newsprint go to Edit>Convert to profile and choose a newsprint profile. Converting, rather than assigning a profile, changes the pixel values in the image and no profile is embedded, the image is altered to conform to the selected profile. If you are using PDF-X/1a then it is stripping out embedded profiles anyway.

I cannot say how the newspapers are pre-flighting files, there are many pre-flight applications available and most are customizable. In our shop pre-flight checks images for color space and resolution but not TAC, we are a commercial sheetfed shop and TAC's of 300% are acceptable. Pre-flighting assures that supplied files meet the minimum requirements for reproduction set by the printer and is usually not a part of color management.

Color management (in our shop, which is fairly typical) starts when the files are ripped. The color values on the ripped pages match colors on the customers supplied files. We have profiled our presses using GRACOL standards. Color proofs are output using these profiles to show a proof that will match the press sheet. When plates are output additional curves or profiles are applied at the plate setter to account for dot gain. All of this happens in the background and is invisible to the customer - our goal is for proofs to show exactly what the press sheet will look like and for press sheets to match the customers original files as close as possible.

In short, 'Convert' to newsprint profile in Photoshop. No need to embed profile. Send PDF-X/1a files and you'll be fine.

Hope this helps,
Glen Demers
Adobe Certified Expert, Photoshop 7
Prepress Technician, Best Printing Online
www.bestprintingonline.com

For more Photoshop tips please visit our help pages here