In this Instructable, I will show you how to make real blueprints. Inspired by art in the mechanical engineering wing at my college, I set off to rediscover the art of cyanotype and the process used to make blueprints. While attempting this, to my luck, many of the days were cloudy, rainy or even snowy, so I learned and documented how to do this entire process while spending time inside the house. As this is my first Instructable, please let me know if there are any suggestions or questions!

Supplies

To get started, you will need the following:

Base paper - This will become the blueprint so I used some thicker sketching paper I had available (here's a similar version)

Tracing Paper - This will be used to transfer the desired image onto the base paper or if you have a laser printer, transparency film can be used for shorter expose times
Cyanotype Liquid - This will be used to treat the base paper to make it become light-sensitive and turn blue when exposed. It comes in 2 bottles - a Part A & B

Hydrogen Peroxide - Used to make the blue of the print really pop and can be bought from a local pharmacy such as CVS or Walgreens

Pipettes (2) - Used to Measure out Cyanotype liquid, one for each of the two bottles

Foam Brush - For painting on the cyanotype solution

Disposable container - For mixing the cyanotype solution in

Paper Towel and Newspaper
Pair of plastic/nitrile gloves
A dark spot to dry your base paper or a hair dryer to speed up drying
A sink with a plug or platic tub to wash the print after exposure
Clips/clothespins for all 4 corners and a line/shower curtain rod to hang dry your print
Access to photo editing software - like GIMP (free)
Worklight - Used to expose the cyanotype to UV rays. A UV light or the sun can be used as an alternative

Plexiglass sheet - Holds the tracing paper and base paper together during exposure and can be bought at a hardware stores

Step 1: Prepare the Paper

Prepare the paper layers for the blueprint. First, start by cutting the tracing paper and base paper down to 8.5" x 11" size which is standard for a printer. Set aside the tracing paper for now. Then make sure the lighting and light coming into your workspace can be substantially dimmed as the chemicals are light sensitive. Now put on a pair of plastic/nitrile gloves and complete the following steps:

Cover your work surface/table with newspaper - 11x17 or so to give you extra room around the print you are about to make. Then cover with a layer of paper towel and finally the base paper you cut down to size.
Take the two bottles of cyanotype liquid (parts A and B) and measure out about 5ml of each liquid using the pipettes into a disposable container. I recommend having a separate pipette for each bottle as to not cross-contaminate them.
Mix the solution with the brush (which should be enough for 1 sheet of paper)
Apply solution with brush strokes going from top to bottom across the base paper and left to right from top to bottom - making sure to paint off the edge of the page on all sides to ensure the edges and corners are covered for a complete print
Let it dry - storing it somewhere dark and dry for several hours. Alternatively, you can speed up the process using a hairdryer on low heat.

Your base paper should now be ready for exposure, but before that, we need an image to project onto it.

Step 2: Choosing a Design

Now we need to choose a design for the blueprint. You can make your own or use an existing image. When choosing the image, important factors are:

Large image resolution (1:1 is best) - so it will fit the size of the paper without losing quality or causing pixelation and produce cleaner lines
Monochromatic color scheme - if the picture uses a background that has a gradient, it will be harder to properly expose it, so choosing one with only two colors works best
Simplistic Design - pictures with shading or complex backgrounds such as grids will not turn out as well

Once you have picked an image, download the image and import it into a photo editing software, I used GIMP which is a free to use editor which can be found here.

Step 3: Preparing the Photo

Once you have imported the photo into the photo editor software, start by cropping out any extra background that is not connected to the design. Then convert the photo to black and white. Keep in mind that anything black will become white in the final blueprint as the image acts as a negative for the cyanotype. In GIMP you can do this doing the following:

Under the Image tab at the top, go down to Mode then select Indexed
A conversion options window will pop up, select Use black and white (1-bit) palette
The image should now appear as pure black and white, but in this case, the colors need to be inverted as the black will become the white of the final print. Under the Colors tab, go down to Value Invert
The image is now ready

After the photo/image has been prepared, load your printer with the tracing paper and print the image (in GIMP you can press Ctrl + P to print directly from the editor).

Step 4: Expose the Cyanotype

With both the treated base paper and the printed image on tracing paper now ready, it's time to expose the base paper.

Start by placing the base paper on a clean flat surface
Then lay the tracing paper directly on top of it with the sides aligned
Cover the paper stack with the sheet of plexiglass to ensure both papers are flat and contacting
Place the work light approximately 15" above the plexiglass (give or take 4") and turn it on and expose the tracing and treated base paper for approximately 1.5 hours. My worklight puts out 5000 lumens (LED) so your exposure time may vary based on the lighting source you use.
While exposing, the room should be dim with no additional ambient light (cover windows & turn off other room lights)

After the exposure, the paper should look almost grey with the lines being blueish but don't worry as the color will change after the wash.

Step 5: Wash the Blueprint

Fill a sink or tub container with enough water to submerge the blueprint, then add a cap full of hydrogen peroxide to the water and stir to mix it in. Then place the exposed paper into the water and gently agitate it for 30 seconds. The paper should start turning blue while the lines from the image should wash out, becoming white. Remove the blueprint and let it dry. For best results hang the print up and secure all corners to prevent curling.

Step 6: Your Finished!

After drying the blueprint should have finished turning a deep blue, giving you a fantastic blueprint! This was my first Instructable so if you have any suggestions or questions please ask!

If you enjoyed or found this helpful I would appreciate your vote in the Paper Challenge contest below!

Step 7: What When Wrong...

It took many tries to get a final result that was sharp and a deep blue-print. To help you troubleshoot any issues you might have, I have included images of my failures with a description of what caused it to fail. I hope that will help you out if you encounter the same!