THERE IS AN ONGOING battle between the art department and the production department that involves the number of screens necessary on artistic images. The one thing that everyone agrees on is that if you print fewer colors and achieve the same result, you will make more money. The tricky part of this is how to effectively combine or eliminate colors in an image while still maintaining the same quality as the original.

What good is it to save money if the image is too far from the original and doesn’t look appealing to the customer? Achieving a balance between cost savings and visual reproduction is a goal in both the art and printing departments. The final resulting design should be a win-win between satisfying the customer’s desire to have a bright vibrant reproduction and a safe use of the necessary colors in the design to produce as many colors as possible.

The tools in Photoshop provide a perfect three-step solution to the issue of reducing the color palette in an image. All it takes is careful analysis of the image, controlled selecting of specific colors, and then replacing the colors with a simpler palette. It is surprising how these simple steps can significantly both improve the image’s printability, but also make the design far more appealing in the finished garment with less colors and a higher profit margin.

For some reason, many printers don’t take the time with simple pre-separation image enhancements because they prefer to deal with images on press and leave any adjustments to the original artists that created the designs. The problem with this is that creative artists who develop designs for screen printing rarely create their work with printing profit margins and limited palettes as a consideration. What this causes is that the artwork provided in-house at screen-printing companies truly is never optimized for best reproduction with the fewest colors.

Makin’ It Right

Editing an image or design that wasn’t developed by your company sometimes can be touchy. It is important that the customer is aware of the changes and make sure the reasoning behind the corrections is approved. A helpful tool to this is a generic piece of art that is shown with both before and after correction that illustrated the necessary changes and how they were achieved.

The other issue is whether or not the time in correcting the artwork can be charged or not. This depends on the client and the relationship that he has with your business. Many shops will not charge for this type of editing because the primary function of the edits is an advantage to the screen printer rather than the customer. Occasionally this type of edit can be sold because the final separation set will provide the customer with a considerably expensive print because of the reduction of printed colors and screens necessary.

Be careful with this though. Some designs are difficult to tell if they can be effectively minimized in color depth until it is attempted. Promising a certain result without testing it on the specific art in question really can put you behind the eight ball if it turns out that the image won’t work in the quoted number of colors. In that scenario no one is happy — the client or the printer. The best action to take is to offer the test at a little or no art charge and then attempt to reduce the colors without making a hard promise or estimate ahead of time. This will make everyone happy without the pressure of the expectations of achieving a savings until it is proven to be workable.

This process is particularly important if your company is provided with a lot of scans of 4-color process printed work or full-color photos from advertising and marketing firms. These types of jobs typically will have a lot of color pollution in what looks like solid areas of color. When you zoom in on jobs that have been scanned from a four-color photo, the colored dots easily will be apparent. They also will be frustratingly hard to properly color separate into usable colors that will look good on a final printed piece. The idea is to quickly edit these types of files so they can be reproduced in a quality fashion using the least amount of colors.

A similar challenge to submitted photos and printed work is artwork that is created by illustrators and graphic designers who are unfamiliar with the typical limitations of simulated process screen printing. In these cases, the artwork that your art department is given is loaded with extra colors in an attempt to create a rich-looking illustration or layout. What they have really given you is a massive headache as you will have to reproduce all of these extra colors and fuss around with the art and seps in a long process of color matching and film positive or screen revisions.

An example of such a piece is the lion image that was created for a martial arts competition (Figure 1). In a casual inspection, this artwork appears to be relatively simple to separate, but when the lion is zoomed in on it quickly shows a wide range of color variation that is sure to play havoc with simple attempts to separate out a fair reproduction using minimal amounts of screens. Instead of getting into the separation preferences and methods that would work best, it is a great idea at this point to crunch down the colors in the image to a simpler version that will save a lot of time in the printing process.

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Analyze the Image

Analysis of an image is not as technical as it sounds. The fascinating part of this beginning process is how simple it is for the human brain to do it, yet no one has even come close to designing a software system that can imitate it. The only analysis of an image that is required is to take a careful look at the art and decide what the minimum number of colors is that are necessary to recreate it. At the same time, it is useful to squint your eyes at the design so it becomes slightly blurry and try to see what the most saturated colors are (these are the colors that are deepest in color hue) that cannot be created with other colors in the design.

Typically, these colors will be ones that are primary or secondary in nature (red, blue, green, yellow, orange, or purple). Yes, it’s true you can make secondary colors out of primaries, but experienced printers will know that highly saturated secondary colors are very difficult to effectively reproduce and tend to be unpredictable on press. So it is a good idea to include them in the unable-to-reproduce list.

You can make quick work out of this step by listing the colors you feel are necessary on a Post-It note and see what you have to start with. At this point you can begin to plan what you will attempt to crunch down or must live with as a necessary screen. With the preliminary analysis done, you can move on to the more challenging areas of the color modification.

The lion image required at least 10 colors on initial analysis (Figure 2). This was not going to work for the client, so the next step in color editing had to take place. This meant isolating and selecting the areas in the design that could be crunched together to minimize extra colors.

There is a definite component of artistic vision in selecting areas in an image to crunch colors down. Just minimizing colors in an image without a careful plan will constitute a similar result to desaturating the image and taking away a lot of the vibrancy and impact that it possessed. The important artistic considerations are lighting, visual planes of structure, and overall appeal. Lighting is a function of how the design is created with a light source in mind.

Some artwork will not have a noticeable light source in the image. But most artwork has been illustrated to look dimensional with a directional lighting that comes from somewhere in space around the design and affects where the highlights and shadows fall.

The planes of structure in an image are the underlying structural shapes that create the image. An easy way to consider this is to think of the design as a cubed shape that has several sides on it that is then lit by a directional light source.

A dramatic example of this with the lion artwork shows how the planes of the lion’s head are being affected by the light source (Figure 3). Drawing this as a reference for color correction obviously is not necessary, but it does illustrate how the planes that are similar in lighting are good areas to group together when color reducing to achieve an artistic result that works the best way with the image that has been illustrated.

Photoshop is both unique and frustrating in the number of ways that are possible to accomplish a complicated selection. You can use paths, the magic wand, the lasso tool, or even paint in a channel or layer to make a selection of an area in an image. For this type of color minimization, the method that works best tends to be the one that flows with the way the design is illustrated. If the design is a simple geometric shape, the simpler tools for selecting (such as the magic wand or the lasso tool) should do the trick.

When the design is complex and illustrated with texture or pattern, it can be useful to use a more precise or artistic method of selecting areas of color such as the path tool. Or, as in the example image, painting in an overlapping layer as a mask. You can just create a layer and paint in a color that is not in the image (like a hot red or bright green) over areas that are similar in color, on similar planes, and share the same lighting values (Figure 4). Continue to do a separate layer for each area in the image that needs to be corrected.

Don’t forget cool shortcuts like Ctrl-clicking on the layer to make a quick selection of the painted layer’s information and then inverting this selection and subtracting other painted layers from this (by Ctrl-clicking on them with the shift key depressed). This makes quick selections of other areas that are around the painted layers.

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A Simpler Palette

The final step in this process is impressively easy and often will make a design look even more appealing because it can unify images that previously were scattered looking with a lot of excess colors. All you must do at this point is make a duplicate layer of the image that is to be corrected for safety’s sake (and so you can reference or use the original as a backdrop). Then, make selections from the painted mask layers by Ctrl-clicking on them (on a Mac it’s Command-click).

With the selections active, you will see the crawling ants around a rough idea of what your selection should be. You can then open the hue/saturation menu and use the colorize button and the hue/saturation/lightness sliders to get a good combination for the selected area. Don’t worry if the change is too drastic looking at this point; the main idea is to get the hue and saturation right. It is rare that the lightness needs to be changed a lot.

When you are finished with colorizing the selected areas in the image, compare it with the original. If it looks like too much of a change or it’s unappealing, then you can create a new duplicate and redo it or lower the opacity of the edited layer and merge it with the original. Often it is this combination of a merged colorized version and the original layer as a backdrop that will provide a great compromise between a complete color-changed version and the original image. With the edits done to the lion, the colors necessary to reproduce it dropped to six colors (Figure 5).

It’s easy to see how a simple process of crunching colors together can save a tremendous amount of separation time and anxiety on press with color matching and wasted extra colors. The careful application of this process can enhance artwork and not make it flat looking while increasing the profit margin and lower setup costs for both the printer and the client.

With established clients and high-volume orders, it can be important to execute this process on an image before the approval stage so everyone is in agreement to how the final image will be reproduced. Also make absolutely sure that the reduction in colors is going to achieve an acceptable result. With practice and realized savings over time, this method could become a standard procedure in your shop that will continually add to your bottom line.

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