Sign Up Now
Twitter Facebook Flickr Buzz
PhotoshopSociety.org
 
Search:   
 
Social Networks

LOGIN     

Go
Forgot Password? Go Join Now
Sign Up for Starter's Pack (Free)
Call (800) 223-8720
Email custserv@photoshopsociety.org
 
Need Web Solutions? Get Free Sample Issue

Inside Photoshop: Search Articles

  Search Library:  
 
2018 |  2017 |  2016 |  2015 |  2014 |  2013 |  2012 |  2011 |  2010 |  2009 |  2008 |  2007 |  2006 |  2005 | 
 

Demystify duotones for perfect two-toned images

Added on Friday 27th of January 2006 03:09 am EST
 

Application:

Adobe Photoshop 7/CS/CS2

Operating Systems:

Macintosh, Microsoft Windows

Keywords:

Photoshop, Duotone, Color Mode, Tonal Range, Curves

 

Long a staple of budget-conscious designers, duotones are sometimes overlooked by Photoshop users because they don't behave like images in other color modes. While most people can create a duotone, getting it to actually look good is another story. We’ll clear up the mystery of the creation of duotones and tell you what you need to know to get the perfect duotone every time.

 

To get the best looking duotones, we’ll:

     Define duotones for a quick trip back to the basics.

     Discuss the tone-enhancement concepts behind duotones and their most common uses.

     Show you how to create your own duotones and modify them to create a rich color-balanced image.

     Tell you how you need to save your file for use in common page layout programs and some other output methods.

 

Between the simple monotone of black-and-white printing and the rich rainbow tapestry of process color lurks the shadowy realm of duotones. Many people have a hard time getting their duotones to look the way they want, so they avoid them completely. We’ll confront the problem in this article and show you how to conquer your darkest duotone fears.

 

Back to the basics

Using the simple color features of your layout application, you can crudely simulate the effect of a two-color duotone using background coloring. But that’s a fake duotone. Real duotones are grayscale images reproduced using two colors of ink, usually black and a spot color such as those used in the PANTONE color system.

In Photoshop terms, duotones is used to also refer to grayscale images reproduced as monotones (i.e., with an ink color other than black), tritones (using three inks), or quadtones (using four inks). Photoshop’s Duotone color mode is used to create all four types, and all four types produce only one channel each.

 

The many faces of a duotone

The primary purpose of a duotone is to expand the tonal range in a printed grayscale image. However, they are also used for lower cost 2-color print jobs, and for lightly tinting images with color.

 

Shades of gray

Even though a grayscale channel in Photoshop can contain up to 256 shades between white and black, a traditional printing press has a much more limited range. At best, a printed black-and-white image can only replicate about fifty shades of gray. With a duotone you can overcome this limitation by adding a second gray ink to the image, theoretically adding another fifty shades to the image. You can see the comparison of a standard grayscale image and a duotone in Figure A. The grayscale image printed with only black ink lacks tonal value compared to the tonally rich duotone.

 

A

 

 

 

Note: While many of the examples in this article use spot colors, Inside Photoshop is printed using standard four-color process. Thus, we’ve actually had to cheat a bit by converting our spot examples to CMYK mode.

 

 

Cost-cutting measures

A much more common use for duotones is to transform a full color image into two colors, for use in two-color print jobs. By using spot colors to add color tints to halftones, duotones can provide an economical alternative to full-color printing. An example of this type of color tint, using black and Pantone Blue 072 CVC is shown in Figure B.

B

 

Sepia duotones

Let’s not leave out the most widely recognized duotone, a more subtle sepia tint. You can create a faux sepia duotone using black and Pantone 722 C as we have in Figure C.

C

 

Analyze your image

The most important step in creating a duotone isn’t in the mechanics; it’s selecting a high-quality image. Here are some guidelines to help you choose the right image:

        Tonal balance. Look for an image that has a good tonal balance and solid contrast. That means an image with a consistent range of highlights and shadows, without going overboard on either. A duotone won’t rescue a poor quality image, so choose wisely.

        Color Mode. Your image needs to be in the Grayscale color mode before you convert it to Duotone. You can’t make a duotone from an RGB or CMYK color mode image.

        Resolution. Since this article assumes you’ll be using the finished duotone in print, be sure to select an image that has sufficient resolution for the type of paper you plan to print on.

 

Create a duotone

As we stated earlier, the act of creating a duotone is a simple process. Once you’ve toiled over your image selection, you can begin.

 

To create a duotone:

1.       Open an 8-bit grayscale image in Photoshop, or convert an image from another color mode to grayscale.

 

 

Note: You should make any necessary contrast adjustments with the Curves or Levels controls before you continue to ensure you have a good tonal balance.

 

 

2.      Select Image > Mode > Duotone to display the Duotone Options dialog box.

3.      Select Duotone from the Type pop-up menu as shown in Figure D.

D

 

4.      Click the Solid Ink Color Box in the Ink 2 row, located directly below the all-black box, to open the Custom colors dialog box.

 

 

Note: If the Color Picker dialog box opens instead, just click the Custom button to open the Custom Colors dialog box. While creating duotones from Pantone swatches is most common, you can use any book you want. Or, use the Eyedropper tool to select a specific color from your screen.

 

 

5.      Select a library from the Book pop-up menu to choose a color from.

6.  &...