I Looked at a Flyer Under a Microscope… and Uncovered the Hidden Secret of Printed Color (The Three Primary Colors of Pigment)
I’m Ken Kuwako, a science trainer. Every day is an experiment.
Do you know about the three primary colors of pigments? In junior high school, we mainly learn about the three primary colors of light (red, blue, and green), so you may not get many chances to encounter the three primary colors of pigments (magenta, cyan, and yellow). But these three colors have a surprisingly fascinating story to tell!
For example, if you take a close look at the colorful “O” in the SDGs logo under a microscope, you will discover a world you probably never expected to see.
A surprising discovery under the microscope
Take a look at this video.
Look closely, and you may notice something unexpected:
“Wait… aren’t there surprisingly few colors?”
When we zoom in even further with the microscope, something amazing becomes clear: the image is made up of just three colors—red, blue, and yellow!
There is one important detail, though. Strictly speaking, the “red” is actually a slightly pinkish color, the “blue” is closer to cyan, and the third color is yellow. By combining these three colors in different proportions, printers can create that wonderfully colorful rainbow of hues.
Look at “meat” under a microscope… and prepare to be amazed!
I tried the same thing with a supermarket flyer. I learned about this wonderful teaching material from Eiji Komori, a fellow teacher. It is perfect for getting students excited the first time they use a microscope. He calls it the “Secret Ruler”!
Something has been stuck onto this ruler, right? But can you guess what it is? Believe it or not, it is a photograph of “meat” from a supermarket advertisement!
Let’s take a look at this “meat” under the microscope. What appears is absolutely fascinating:
A dense sea of tiny dots!
What looked like a solid pink color was actually made up of countless tiny, colorful dots. Small dots of red, yellow, blue, and other colors were working together to create the appearance of meat. When I saw it, I couldn’t help thinking:
“So this is how they make that pinkish color of meat!”
We may think we understand how printing works in theory, but actually seeing it with our own eyes is a completely different experience. It is genuinely exciting!
Following letters under a microscope is also a great way to get used to moving the microscope stage. Since everything appears to move in the opposite direction from the way you move the stage, students often struggle at first: “Wait, which way am I supposed to move it?” But that hands-on experience of “Let’s find it!” naturally becomes practice for handling the microscope.
You can also experience the three primary colors of pigments yourself by coloring with colored pencils. Try using pink, light blue, and yellow pencils.
A small idea can make a science lesson much more fun!
I was impressed by the simple idea of having students learn how to move a microscope while following letters. It made me think, “So that’s how you turn a science lesson into something fun!”
By the way, when observing printed materials under a microscope, shining an LED light from the side can make the details much clearer. Give it a try! You can really see how different combinations and amounts of these colors produce all sorts of other colors. This is physics in action, and there are so many things that only become apparent when you magnify them under a microscope.
One more thing: even if you are simply looking at the advertisement, you may have trouble focusing unless you place it on a microscope slide. Printed advertisements do not let much light pass through, so depending on the microscope, it can help to use a small penlight to illuminate the sample from above.
Colored paper and computer screens: is yellow really the same yellow?
I also decided to take a look at the color of a colored sheet of paper. What would we find?
In this case, we can actually see the yellow itself.
But what happens when we look at yellow displayed on a computer screen?
This is what we see. Even though both are called “yellow,” their microscopic structures are completely different. The yellow on colored paper is produced using the three primary colors of pigments (yellow, cyan, and magenta), while the yellow on a computer screen is created by combining the three primary colors of light: green, blue, and red.
Isn’t it fascinating that two colors that look exactly the same can be produced by completely opposite mechanisms? You can read more about the three primary colors of light here.
The difference between the three primary colors of light and pigments
The three primary colors of light that we learn about in junior high school are red, blue, and green. When these colors are combined, they can produce white light.
・Three primary colors of light → Red, Green, Blue (RGB)
The three primary colors of pigments, on the other hand, are magenta, cyan, and yellow. These are used for inks, paints, and other pigments, and as they are mixed together, the resulting color becomes darker and approaches black.
・Three primary colors of pigments → Magenta, Cyan, Yellow (CMY)
The colors in the “O” of the SDGs logo are also created using this system of the three primary colors of pigments!
Isn’t it fascinating how a microscope can transform familiar everyday objects into something that looks like an entirely different world? Why not grab some colorful printed material or take a look at a screen and magnify it to see what you can discover? Try asking yourself, “What colors are actually being used here?”
I’m sure you’ll never look at the familiar world of “color” quite the same way again.
Contact and inquiries
Let’s bring the wonder and excitement of science a little closer to everyday life! Here you’ll find fun science experiments that you can try at home, along with easy-to-understand tips and tricks. Take a look around and discover something new!
・The content of 科学のネタ帳 is now also available as a book. For more information, click here.
・To learn more about Ken Kuwako, the author and creator of this site, click here.
・For inquiries and requests (writing, lectures, science workshops, TV science supervision, appearances, and more), click here.
・Get the latest updates and new articles on X!
The 科学のネタチャンネル features videos of science experiments!
NEW 分解問題集 理科
- ７月２１日発売！『高校入試 分解問題集 理科』（学研）…難しい問題も小さな問題に分解することで、問題を解くことができます。そんな分解の技術が身につくように深く関わりを持って作りました。
７・８月のイチオシ実験！
夏でプシュッと爽やか実験！
テレビ番組監修・イベント等のお知らせ
- ７月３０日（水）科学監修「TIF presents ONE SONG FES」（フジテレビ） 26:15~27:15
- 12月26日（土） ナリカサイエンスアカデミー（教員向け実験講習会）開催
書籍のお知らせ
- 『大人のための高校物理復習帳』（講談社）…一般向けに日常の物理について公式を元に紐解きました。特設サイトでは実験を多数紹介しています。※増刷がかかり６刷となりました（2026/02/01）
- 『きめる!共通テスト 物理基礎 改訂版』（学研）… 高校物理の参考書です。イラストを多くしてイメージが持てるように描きました。授業についていけない、物理が苦手、そんな生徒におすすめです。特設サイトはこちら。
各種SNS（更新情報をお届け！）
【日本語】X(Twitter)／instagram／Facebook 【英語】BlueSky／Threads
Explore
- 楽しい実験…お子さんと一緒に夢中になれるイチオシの科学実験を多数紹介しています。また、高校物理の理解を深めるための動画教材も用意しました。
- 理科の教材… 理科教師をバックアップ！授業の質を高め、準備を効率化するための選りすぐりの教材を紹介しています。
- Youtube…科学実験等の動画を配信しています。
- 科学ラジオ …科学トピックをほぼ毎日配信中！AI技術を駆使して作成した「耳で楽しむ科学」をお届けします。
- 講演 …全国各地で実験講習会・サイエンスショー等を行っています。
- About …「科学のネタ帳」のコンセプトや、運営者である桑子研のプロフィール・想いをまとめています。
- お問い合わせ …実験教室のご依頼、執筆・講演の相談、科学監修等はこちらのフォームからお寄せください。
