Why are blueprints blue? – Big Questions – (Ep. 206)

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In this lesson, Craig explains the historical significance of blueprints, which were originally blue due to a chemical process involving ammonium iron citrate and potassium ferrocyanide that allowed for easier and cheaper copying of architectural designs. The blue color results from a chemical reaction that creates a blue compound, while the areas blocked by the original design remain white. Although modern technology has largely replaced blueprints with photocopies, the unique history and process behind blueprints remain an intriguing aspect of architectural and engineering practices.

Why Are Blueprints Blue?

Hey there! I’m Craig, and today we’re diving into a fascinating question: Why are blueprints blue? Let’s explore this interesting topic together!

The Origin of Blueprints

When we hear the word “blueprint” today, we might think of any kind of plan or design, regardless of its color. But originally, blueprints were always blue. This was because they were made using a special process that only produced blue copies.

How Blueprints Were Made

Before blueprints, architects had to trace their designs by hand every time they needed a copy. This was time-consuming and expensive. The invention of blueprints in the mid-1800s changed everything. It made copying plans much cheaper and easier.

The process involved using a special chemical solution made from ammonium iron citrate and potassium ferrocyanide. Here’s how it worked:

  • First, a sheet of paper was coated with this solution and left to dry.
  • The original design was drawn on cloth or tracing paper.
  • The coated paper was placed under the original design, and a bright light was shone on both.

This light caused a chemical reaction, turning the paper blue. The lines of the original design blocked the light, so those areas stayed white. The result was a blueprint, which is like a photographic negative.

Why Blue?

The reason blueprints are blue is due to the chemical reaction that occurs during the process. This reaction creates a blue compound called ferric ferrocyanide, which doesn’t allow for other colors or shades.

Modern Alternatives

Today, making copies is much easier with photocopiers, which were invented in the 1930s and became widely used in the 1960s. However, architects and engineers continued using blueprints for a long time. It wasn’t until the early 2000s that most of them switched to photocopies.

Now, if someone wants a blueprint-like copy, they often use a “white print.” This is the opposite of a blueprint, with white paper and blue lines. White prints use different chemicals that are less toxic than those used in traditional blueprints.

Conclusion

So, there you have it! Blueprints are blue because of a unique chemical process that was invented to make copying designs easier and cheaper. While technology has advanced, the history of blueprints remains a fascinating part of architectural and engineering history.

Thanks for exploring this topic with me! If you have any other big questions, feel free to ask. See you next time!

  1. What surprised you the most about the historical process of creating blueprints, and why?
  2. Reflect on the significance of the blueprint process in the 1800s. How do you think it impacted architectural and engineering practices at the time?
  3. How do you feel about the transition from traditional blueprints to modern photocopies and digital designs? What are the pros and cons of each method?
  4. In what ways do you think the invention of blueprints influenced other industries beyond architecture and engineering?
  5. Consider the chemical process described in the article. What are your thoughts on the use of chemicals in historical and modern design processes?
  6. How do you think the concept of a “blueprint” has evolved in contemporary language and culture?
  7. What are some other historical innovations that you think have had a similar impact on their respective fields as blueprints did on architecture?
  8. After learning about the history of blueprints, how do you view the role of technology in shaping the future of design and planning?
  1. Create Your Own Blueprint

    Try making a simple blueprint of a room in your house. Use graph paper to draw the layout, including furniture and windows. Remember to use a ruler for straight lines and label each part of your design. This will help you understand the precision needed in architectural plans.

  2. Chemical Reaction Experiment

    Conduct a safe experiment to observe a chemical reaction. Mix baking soda and vinegar to see how substances can change when combined. This will give you a basic understanding of how chemical reactions work, similar to the blueprint process.

  3. Blueprint History Timeline

    Create a timeline that shows the history of blueprints, starting from their invention in the mid-1800s to modern alternatives. Include key events and technological advancements. This will help you visualize how the process evolved over time.

  4. Design a Future City

    Imagine and draw a futuristic city using blueprint-style techniques. Think about how buildings might look and function in the future. Use your creativity to include innovative structures and sustainable solutions.

  5. Blueprint Scavenger Hunt

    Go on a scavenger hunt to find examples of blueprints or architectural plans in your community. Visit a library or a local architect’s office, if possible. Take notes on what you find and share your discoveries with the class.

Sure! Here’s a sanitized version of the transcript:

Hi, I’m Craig. I’m an ex-Blue Man—not part of the group, just a man who was blue. This is Mental Floss on YouTube. Today, I’m going to answer David’s big question: Why are blueprints blue?

Nowadays, “blueprint” refers to any sort of plan, whether it’s blue or not. But originally, blueprints had to be that color because they were copies that could only be made in blue. Let’s get started!

The process of making copies may seem simple now, but architects used to have to do it by hand, tracing copies whenever they needed one. Experts estimate that the invention of blueprints reduced the cost of copies to one-tenth of what it originally was, and you didn’t have to draw all the time. Blueprints were invented in the mid-nineteenth century because people needed a better way to reproduce plans for architecture and other projects. Some scientists discovered that a combination of ammonium iron citrate and potassium ferrocyanide created a solution that could help with this.

To make a blueprint, you coat a sheet of paper with that solution and allow it to dry. Then, you create the original plan on cloth or tracing paper, place a sheet on top of the paper that will be blueprinted, and shine a bright light onto both. This is when the solution reacts and creates a new compound of blue ferric ferrocyanide. The reaction turns the paper blue, while the lines on the original plan block the bright light, so the blueprint stays white where those lines are. Essentially, a blueprint is a negative, and the reason blueprints are blue is that the chemical reaction doesn’t allow for other colors or shades.

Of course, nowadays it’s pretty easy to use a photocopier, a technology invented in the 1930s that became mainstream in the 1960s. However, it took architects and engineers a while to switch away from blueprints. In fact, the majority of those two fields turned to photocopies during the early 2000s. If architects or engineers want a blueprint-like copy nowadays, they tend to create a white print instead—essentially the opposite of a blueprint, with white paper and blue lines. White prints require diazonium salt and a dye, which are less toxic than the chemicals used in blue printing.

Thanks for watching Mental Floss on YouTube! If you have a big question of your own that you’d like answered, leave it below in the comments. See you next week!

Let me know if you need any further modifications!

BlueprintA detailed plan or drawing that shows how something is designed or built. – Engineers use a blueprint to ensure that the bridge is constructed correctly.

ChemicalA substance with a distinct molecular composition that is produced by or used in a chemical process. – In science class, we learned how mixing different chemicals can result in a reaction.

DesignThe plan or blueprint created to show the look and function of a building, machine, or other object before it is built or made. – The design of the new smartphone includes a larger screen and a faster processor.

ProcessA series of actions or steps taken to achieve a particular end. – The process of photosynthesis allows plants to convert sunlight into energy.

ArchitectsProfessionals who design buildings and often oversee their construction. – Architects must consider both aesthetics and functionality when designing a new school.

LightA form of energy that is visible to the human eye and is responsible for the sense of sight. – Light travels faster than sound, which is why we see lightning before we hear thunder.

ReactionA process in which substances interact to form new substances with different properties. – The reaction between vinegar and baking soda produces carbon dioxide gas.

CompoundA substance made up of two or more different elements that are chemically bonded together. – Water is a compound consisting of two hydrogen atoms and one oxygen atom.

PhotocopiersMachines that make paper copies of documents and other visual images quickly and cheaply. – Photocopiers use light to transfer images from a document onto paper.

HistoryThe study of past events, particularly in human affairs or the development of a particular subject. – The history of electricity includes the discovery of the electron and the invention of the light bulb.

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