Introduction: Color Photo Breakdown and Build Up - Exploring the REAL Primary Colors

By The STEMAZing Project
About: The mission of The STEMAZing Project is to provide high-quality professional development for educators to engage and empower their students with authentic, relevant, and developmentally appropriate learning op…

Have you ever wondered how the colored inks in your printer work together to create a full color photograph? Follow along as we show you how to decompose a full color photograph into the primary colors of ink and then recompose the full color image one primary color at a time. The photo being used for this project an either be taken live using a computer webcam or uploaded from a file. Great for teaching how our eyes detect color as well as teaching the REAL primary colors of paint/pigments/ink - which are NOT red, yellow, and blue. The REAL primary colors of paint/pigments/ink are actually cyan, yellow, and magenta (and for printing purposed we also use black ink). These colors for inks are usually labeled CYMK - cyan (C), yellow (Y), magenta (M), and black (K). Let's get started!

Supplies

Computer or device with internet access

Color printer

Transparency film for your printer

Scissors

White piece of paper

Step 1: Take a Colorful Color Photo and Decompose It

You can decompose a color photo into its primary colors in one of two ways - with Webcam or by File Drop. Both are detailed below. Make sure the photo you take or use from a file has lots of bright colors to make this project even more impressive when recomposing the full color photo.

Decomposing a Color Photo with Webcam

Using JavaLab's CMYK Decomposer (with Webcam) with Safari for IOS or with Microsoft Edge or Google Chrome for Windows or Android, capture a colorful color photo which the site will decompose into its cyan, yellow, magenta, and black components for you.

Decomposing a Color Photo from a File

Using JavaLab's CMY Color Division by File Drop take a colorful color photo with your phone or digital camera, upload it to your computer, and then drop it on this site. The JavaLab page will then decompose it into its cyan, yellow, magenta, and black ink components.

Step 2: Screenshot

Once you have a decomposed color photo on one of the JavaLab sites, take a screenshot of the four images created showing the cyan, yellow, magenta, and black components of your photo.

Step 3: Insert, Crop, and Print

Using Word or Google Docs, open a new document. Change all the margins (top, bottom, left, and right) on the document to 0.5" and shift the orientation to landscape.

Insert the screenshot you took of your decomposed photo. If necessary, crop the image to edges of the rectangle of the four color images.

Next, print the document onto a transparency film using a color printer.

Step 4: Cut and Setup

Carefully cut the four color images out. The more accurate you are with this step the better your recomposed picture will look when aligning the four images on top of each other.

Place the four images on a white sheet of paper as shown.

Step 5: Recompose to Full Color Photo

One at a time, layer the cyan, yellow, and magenta image transparencies on top of the black image transparency in order to recompose the original full color photo. The more care taken to align the layers, the better the final, full color image will look.

Wow! Physics!

There are lots of ways to engage young scientists with this project. You can first show them a decomposed image and have them guess what colors they will find in the full color photo. For this image, you might ask, what color are the markers? What color are the stripes on her shirt?

Let them recompose the image themself and ask our two favorite questions: What do you notice? What do you wonder?

They might notice and wonder things like:

  • I notice there are four different colors. (You may have to teach them the color names cyan and magenta.)
  • I notice they all seem to be from the same image.
  • I notice that when I overlap all the colored images on top of the black image, it becomes a full color photo.
  • I wonder if the order you layer the colors matter? (Testable - let them try various orders and then share their observations.)
  • I wonder if what it would look like if you don't use the black image? (Testable - let them try it and then share their observations.
  • I wonder which colors of ink are used to make red? orange? green? blue? violet? (Testable - let them find a color in the full color photo and then observe which colors of ink show up in that area when it is decomposed again.)
    • NOTE: Cyan, yellow, and magenta are the primary colors of paints/pigments/ink. When two primary colors are combined, you create the secondary colors of paints/pigments/ink. For ink, when cyan and yellow are combined, you should see green. When cyan and magenta are combined, you should see blue. When yellow and magenta are combined, you should see red. Different intensities or densities in these ink colors then create all the different shades of colors from orange and violet to everything in between.

Step 6: Explore the REAL Primary Colors Further

If you ask a physicist, "What are the primary colors?", she will ask you a question in return.

Her question will be, "Would you like to know the primary colors of light or the primary colors of paints/pigment/ink?"

Why would she ask this question? Because there are, in fact, two sets of primary colors - one for light and one for paints/pigments/ink. Unfortunately, young scientists have likely learned the primary colors wrong as red, yellow, and blue. This is not the fault of their teachers, as they learned it incorrectly as well. It is our hope that we can correct this misconception for everyone.

When taught correctly, even our youngest scientists can learn the REAL primary colors of light (red, green, and blue) and the REAL primary colors of paint/pigments/ink (cyan, yellow, and magenta).

They can also discover how these sets of primary colors are beautifully connected by exploring the secondary colors. Secondary colors are created by combining two primary colors together to create a new color. In the case of the primary and secondary colors of light, you can see another of our Instructables (#STEMontheCheap RGB Light Show Paper Circuit) above that shows red, green, and blue primary colors of light creating the secondary colors of light on the screen - yellow, magenta, and cyan. In the case of the primary and secondary colors of light, you can see an image of a finger painting lesson where students combine the primary colors of paint/pigments/ink (cyan, yellow, and magenta) to create the secondary colors of paint/pigments/ink (blue, green, and red). NOTE: The blue and red can look a little purple-ish and orange-ish depending on the quality of the paints you have the ratio of the two colors used.

The STEMAZing Project's Primary Colors Collection has lessons for young and older scientists related to the REAL primary colors including a book detailing how the eye sees color, a spinning top young scientists make to experience color mixing in a pHun way, and much more.

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