Sunday, February 01, 2009

Viewing total ink coverage

This weekend I had the good fortune to travel to Canada to speak at the Alberta Weekly Newspaper Association symposium. A question from someone in the audience about total ink coverage (of particular concern when printing on newsprint) in Photoshop led me to ponder how this is treated across the entire Creative Suite.

In Photoshop, you can spot check the ink coverage of individual pixels. Choose Window > Info to display the Info panel. In the Info panel menu, choose Panel Options, and change the Second Color Readout Mode to Total Ink. This will display the total ink percentage for the area under your cursor.

But what if you want to see every pixel at once that exceeds a given ink limit? You can use Acrobat for this. Save the Photoshop image as a Photoshop PDF file. Then open the PDF in Acrobat 8 or 9. Choose Advanced > Print Production > Output Preview. In the Output Preview panel, check the Total Area Coverage option, and choose a percentage. Acrobat will highlight areas that exceed the total ink limit with a bright green highlight.

But what if you're working on a layout, and you want to see if any pages contain any areas that exceed a certain ink limit? This is easy in InDesign. Open an InDesign file, and choose Window > Output > Separations Preview. In the View: drop-down menu in the Separations panel, choose Ink Limit and a percentage. InDesign will change your view of all pages to gray, and highlight all areas that exceed the chosen ink limit with a bright red highlight. This works for placed bitmap and vector images, as well as InDesign text and objects.

Illustrator CS4 now has a Separations Preview panel (Window > Separations Preview) similar to the one in InDesign. But unfortunately, it doesn't have the ability to display Total Ink. So if you need to view total ink coverage for an Illustrator file, you'll have to open it in Acrobat or place it in InDesign.

(By the way, my weekend wasn't all work and no play. I got to cross-country ski at the Canmore Nordic Center. For a flatlander like me, skiing in the shadow of the Three Sisters at the site of the 1988 Winter Olympics was a thrill. Photos here.)


Mark Redman said...


Just found your blog. We have just created a free tool to show CMYK Coverage for Print-Ready PDF files, Its very basic and havent as yet found it viable as a stand-alone product. I Wuuld appreciate you thoughts in where a tool like this might go?

Its available here:

Mark Redman
Made4Print Limited

Keith Gilbert said...

@Mark: I gave your Printcalc site a whirl...pretty slick! I'm afraid I don't have a feel for the marketability of such a product. For what it's worth, I've never been asked by any of my training or consulting clients for such a tool. If there is a niche market for this, I do think offering it as a Web service is the way to go, either on a subscription or ad-supported basis.

bretlinford said...

Hi, Keith.

Thanks for the info. Do you know of a way to change the default value of TAC to something other than 280? Thanks!

Keith Gilbert said...

@bretlinford, I don't know of any way to change the default value to something other than 280, in either AA or ID.

Joy said...

Maybe this is from an update of InDesign in the past year, but I think I have a solution. Though it also functions through a pull-down menu of default densities, I've found that you can type in any percentage in the Ink Limit field in the Separations Preview palette and the red masked area changes to reflect whatever percentage you want.

James said...

Hi Keith,

Very insightful topic. I am have an ad that will be printed on a newspaper. My CMYK image goes over the required total ink limit in some areas (I used ID CS4 to see this). How can I fix this? Is it a matter of tweaking levels in Photoshop until the red dots stop displaying? BTW, the total ink limit is 240%. Thanks for any info you could lend.

Keith Gilbert said...

@James, yes, you will need to edit the image in Photoshop via Levels or other exposure controls to reduce the Total Ink Coverage.

Michael Taylor said...

Coming back to Keith Gilbert: I have adjusted the overall area coverage for a particular ad in Curves. I need extreme Black background, so I adjusted CMYK levels to get 300% Total Area Coverage (TAC). However, in Acrobat (Advanced>Output Preview) select 300% TAC in the drop down at the bottom shows that I still have one or two spots that need tweaking elsewhere on the picture. Back to Photoshop then. How do you adjust those spots to get them below 300% TAC?

Mark Redman said...

Hi All,

Just to let everyone, Printcalc has been updated and supports EPS, PS in addition to PDF. Try it at

Mark Redman