The use of a knockout for black is similar to a Rich Black in that if the color black crosses over two or more different backgrounds, the results can be undesirable. To prevent different value blacks in your design, in this example we will change the color black from overprinting to a black knockout with the use of a custom Knockout Black color build.

We can fix this situation simply by using a custom Knockout Black color build.

Black

Black crossing over two different backgrounds

Enlarged

 

Close-up of [Black] value over two different backgrounds.

Black Deselected

Black separation deselected to show what will print underneath

Knockout Black

Same box with Knockout Black applied instead of [Black]

Black Deselected

Black separation deselected to show what will print underneath with Knockout Black

The simplest way to achieve this is by making a custom process color build that has C=0, M=0, Y=0, K=100 values. All color builds by default knockout, and since the only color value is black at 100% you will get the equivalent of a black knockout.

This technique is not limited to process color project alone. You can use this on spot color jobs with black, when you what it to knockout of any spot colors used.

How to Make a Knockout Black Color

QuarkXPress

QuarkXPress^®

To define your own custom Knockout Black, access the Edit Color dialog box, and Name: your color Knockout Black or anything you want. For the Model: pop-up menu select CMYK, and make sure the Spot Color checkbox is deselected. Apply the values C=0%, M:=0%, Y:=0%, and K=100%. Press the OK button to add your color to the Colors palette.

 

Adobe InDesign

Adobe^® InDesign^® 

To make a custom Knockout Black color build, access the New Color Swatch dialog box. Deselect the Name with Color Value checkbox and  in the Swatch Name: field type Knockout Black or any unique name you like. For the Color Type: pop-up menu select Process and for the Color Mode: pop-up menu select CMYK. Apply the values C=0%, M:=0%, Y:=0%, and K=100%,or use the sliders. Press the OK button when your are finished to add your Knockout Black color to the Swatches palette.

Microsoft Office Publisher

Mircosoft^® Office Publisher^®

To change an Accent color to create a rich black, convert your colors to Process colors (CMYK) and select the Custom tab. Apply 0 for Cyan:, Magenta:, and Yellow:. Then apply 100 for the Black: value. 

 

Microsoft product screen shot(s) reprinted with permission from Microsoft Corporation.