Rainbow Magic: Hexachrome Halftone Stencils (CMYKOG)

In visual art and printing, a spectrum of methods exists to bring images to life with vivid color and detail. One such method is the use of hexachrome (sometimes refered to as ‘CMYKOG’) halftone stencils, a technique that combines the principles of traditional halftoning with an expanded color palette. Hexachrome printing introduces additional hues beyond the standard CMYK (Cyan, Magenta, Yellow, and Black), resulting in more vibrant and precise reproductions. In this post we explore the hexachrome palette, suitable image types, stencil creation, painting order, and more.

What colors are included in the hexachrome palette, and why?

The hexachrome palette expands on the traditional CMYK model by adding two additional colors: Orange and Green. These extra hues significantly enhance the color range, enabling more accurate and vibrant reproduction of images. The inclusion of orange helps to render more realistic skin tones and sunset hues, while green contributes to richer botanical and aquatic shades.

Hexachrome was developed by Pantone Inc. with the intention of overcoming the limitations of CMYK printing. While CMYK is sufficient for many purposes, it often falls short in accurately representing the full spectrum of colors found in nature. By incorporating orange and green, hexachrome narrows the gap, allowing for smoother gradients and more nuanced color transitions.

What kinds of images benefit from hexachrome halftone?

In the fantastic cat image, the CMYK version is pretty successful, but the Hexachrome version is more saturated, and includes more of the natural colors in the image, in particular the orange stripes on the cat are more vivid.

The Peter Pan graphic contains a lot of green, so that shows deeper and with more fidelity in the hexachrome halftone version. Also, the skin tones are orange-y, and the depth is present in the hexachrome version where in the CMYK version you just see stripe-y magenta. Download Peter Pan.

A photographic image (background removed) of a Mandarin duck.

Of course, an orange with green leaves should look better in hexachrome because that method treats those colors almost as spot colors. In this example, for the CMYK version, you would typically go easy on the magenta (if you’re spraying the stencil) so that it doesn’t completely cover the yellow, and get a better effect. But the default treatment leaves you with way too much magenta. Download the orange.

In general, images that benefit the most from hexachrome halftone are those requiring high color fidelity and a broader range of hues. This includes photographic prints where accurate skin tones and natural landscapes need to be depicted with realistic colors. The additional orange and green inks help to bridge the gaps that CMYK leaves, providing a more lifelike and captivating image.

Examples of images that benefit from hexachrome:

  • vivid scenes from nature (especially jungle, rainforest, exotic flora and fauna)
  • images with lots of green or orange (St Patrick’s Day parade, a Clemson tailgate party)
  • ‘riot of color’ images like the Indian Holi Festival
  • images with Pantone spot colors

Images that are better left to CMYK (or even Grayscale):

  • your snapshot of just about anything (seriously, CMYK is going to do great with that)
  • faces, portraits
  • unsaturated images

How to make a hexachrome linear halftone stencil

Creating a linear halftone stencil begins with selecting a digital image and converting it into a halftone pattern. This involves using graphic design software to transform the image into a series of dots varying in size and spacing. These dots collectively form the illusion of gradients and shades when viewed from a distance, mimicking the continuous tones of the original image.

Once the halftone pattern is prepared, the next step is to cut the stencil. This process requires a stencil cutter or a cutting plotter, which follows the digital design to create the stencil on a suitable material like mylar or acetate. Precision is key here, as the stencil needs to accurately reproduce the halftone dots to ensure the final painted image looks as intended.

After cutting the stencil, it’s crucial to ensure it is clean and free of any loose material that might interfere with the painting process. The stencil can then be tested on a sample surface to check for accuracy and any potential issues that need addressing. This preparatory step is vital to achieving a high-quality final result with hexachrome halftone painting.

Search our Gallery for one of our sample images.

When you find one you like, click over to the halftones.

Taylor Swift stencil showing navigation to halftone download page

On the Halftones page, click ‘Download SVGs’

Taylor Swift halftone page
Screenshot

In the dialog that comes up, choose appropriate settings for the download:

Color model: CMYK or Hexachrome to do the comparison in this post

Resolution:

  • up to 60 lines for paper on a craft cutter
  • up to 70 or maybe 80 lines for mylar on a craft cutter
  • up to 100 lines for mylar on a desktop laser cutter
Taylor Swift halftone download dialog

Receive the SVGs by email:

email containing SVG download

Unpack the .zip file to find your 6 Hexachrome SVGs.

SVGs from zip file download

See cutting instructions for any of these methods:

Use your own image to make a Hexachrome halftone stencil

It’s easy!

Upload your own image to Bay Stencil.

When you get the email back with the traditional separations, click on the link for the halftones, and you can follow the rest of the steps above.

If it’s your first upload, it will be free. Otherwise, it’s $3 to unlock the custom image for as many of the stencil variants and halftones as you like.

What order should I paint the hexachrome stencils?

When painting with hexachrome stencils, the order in which the colors are applied can significantly affect the final output. Typically, the process starts with the lightest colors and progresses to the darkest. Do a test with the actual paints you’re going to use, and then follow the order of lightest-to-darkest. With the paints I typically use:

  • yellow
  • magenta
  • cyan
  • orange
  • green
  • black

Black is always last, since it creates the value which is about 90% of how your eye interprets the image.

Exceptions: if your image has a lot of purple in it, and the purple is super important to the image (like, Minnesota Vikings pride day) you may want to paint orange and green before magent and cyan, since the magenta and cyan is what’s going to make the purple (along with the black).

What other interesting color models are there for halftones?

Beyond hexachrome, there are several other intriguing color models used in halftoning. RGK is really interesting, because of the rich browns and earth tones, as well as a variety of realistic skin tones you can achieve. 

The CMYKOGV model, which stands for Cyan, Magenta, Yellow, Black, Orange, Green, and Violet, is another advanced color model. This seven-color system is designed to maximize color reproduction capabilities, making it suitable for specialized printing tasks where the highest fidelity is required. Each of these models offers unique advantages, allowing artists and printers to choose the best method for their specific needs.