Introduction: Colours and Fluorescence #phablabs

About: PHABLABS 4.0 is based on combining the World of Photonics (Science of light and light technologies) with the growing creative ecosystem of existing Fab Labs. The “Photonics Workshops” introduce a variety of fu…

Construct an experimental system, which will allow you to investigate the colour and fluorescent properties of different objects such as highlighter ink, tonic water, vitamin B dissolved in water…

During the workshop, you will perform the following tasks:

1. Assemble an electronic circuit to control an RGB LEDs.
2. 3D print a mount which will hold the electronics in place and through which you can look.
3. Construct a box to block ambient light. The 3D printed mount sits on top of the box and the sample objects are placed in the box.
4. Examine the colour content of various objects by illuminating with different bands of the visible spectrum (a special colour chart can be printed and examined using this experiment)
5. Use an ultra violet (UV) light source or ‘black light’ to investigate the fluorescent properties of some materials and investigate their applications (fluorescent materials such as markers/paints, tonic water, vitamins dissolved in water)
6. Get creative by painting some artworks using regular and fluorescent paints and will look at their appearance under the various lighting conditions.
7. Use your smart phones to capture images of all of the above

Properties of this workshop:

Timeplanning: Total: 2h

1. 3D-print the mount: 30 minutes
2. Prepare box in cardboard: 60 minutes
3. Electronic circuit assembly: 20 minutes
4. Perform colour and fluorescence experiments: 40 minutes

Target audience: Young minds (10-14 years old)

Estimated cost: € 22

DISCLAIMER: By using this information you agree to be legally bound by these terms, which shall take effect immediately on your first use of the information. PHABLABS 4.0 consortium and its member organizations give no warranty that the provided information is accurate, up-to-date or complete. You are responsible for independently verifying the information. VUB cannot be held liable for any loss or damage that may arise directly or indirectly from the use of or reliance on the information and/or products provided. PHABLABS 4.0 consortium and its member organizations disclaim all responsibility to the maximum extent possible under applicable laws: All express or implied warranties in relation to the information and your use of it are excluded. All liability, including for negligence, to you arising directly or indirectly in connection with the information or from your use of it is excluded. This instruction is published under the Creative Commons licence CC-BY-NC.

Step 1: Part List

Photonics parts:

*Hand held UV note checker/black light

Other parts:

*Battery pack
*AA batteries (8x)
*3 switches
*Colour chart
*Fluorescent samples (tonic water, glow-in-the-dark stickers, tonic water, bank notes...)
*Colouring pens
*Cardboard box

Tools (for example in Fab Labs):

*3D printer
*Soldering iron or wire glue

Don't find the material you are looking for? Via this link you could buy all the photonics material needed for this workshop.

Step 2: Assembly of the LED Circuit

Start by 3D printing of the viewer eyepiece and the circuit base. STL files attached.

a) Photo 1: Insert the viewer into the large hole in the circuit base and glue in place.

b) If your battery box has a plug attached to the black and red wires
then remove it by cutting the wires close to the plug. You don’t need the plug.

c) Cut a new hole in the battery box as shown and run the black and red wires through this hole. Photo 2

d) Run the black and red wires from the battery box through the hole provided in the circuit base. Photo 3

e) Glue the battery box to the front of the viewer as shown. Be careful that you put the cover to the front and the switch to the back on the eyepiece side. Photo 4

f) Mount the red, green and blue switches like this and tighten the nuts by hand. Align them so that the pins underneath look like they do in the picture. Photo 5 & 6

g) Glue the RGB module to the front of the viewer so that it’s underneath the battery box with the pins facing towards the switches like this. Photo 7

h) Strip about 6cm of the black wires from the battery box and connect it to the same side of the three switches. You can just run it through the hole in the terminal on the switch and wrap it around a couple of times. When finished it should be similar to this picture. Photo 8

i) Nearly finished. Now get your other 4 wires ready by stripping about 1 cm of the end to expose the wire. Do the same on the end of the red wires coming from the battery box.

j) Twist the ends of the red wire from the battery box and one of the other 4 wires and then connect it to the V pin on the RGB led module. Wrap the exposed wire in a little tape to protect it.

k) Finally connect the second terminal of each of the red, green and blue switches to the R, G and B pins on the led module using one of the 3 wires remaining. Your final circuit should look like this from the bottom. Photo 9

l) Now install the 3 x AA batteries in the battery box and turn the switch to on if there is a switch on the box. When you press each of the buttons the led module should light up with the same colour led.

Photo 10: result of the eye piece

Step 3: Construction of the Box

The box acts as a ‘dark room’ and is very easy to assemble. Any cardboard box can be used. The box shown in photo 1 has dimensions of 420 x 380 x 360 mm (length x width x height).

Three holes need to be made in the box which can be made using a scissors or blade

The first hole is so that the mount can sit on top of the box (as shown in photo 2.). The dimensions of this hole are 70 x 82 mm.
The second hole is to place the black light for UV illumination. The dimensions are 160 x 23 mm.
Thirdly, the bottom of the box is completely cut off. This is so that it is easy to lift the box up and place the samples or artwork inside the box.

Step 4: The Colour Target

The colour target is shown in photo 1. This can be printed using any printer. Note that the three white circles labelled ‘Fluorescent Yellow’, ‘Fluorescent Pink’ and ‘Fluorescent Green’ need to be coloured in after printing using highlighter markers. These act as fluorescent colour samples and will fluoresce under UV light.

When the colour chart is placed in the box, and viewed under various illumination colours, each colour will appear light or dark.

Fluorescent materials and the UV light source

The hand held checker or 'black light' is the UV light source used in this workshops. Photo 2. It is used for viewing fluorescent samples such as yellow highlighter ink as shown on the white page.

Using the LED circuit, the three switches control the red, green and blue LEDs which can be used in any combination to produce white, red, green, blue, yellow, magenta or cyan coloured illumination. Examples of each of these can be seen in photo 3. In addition, the spectra of each combination was measured using a spectrometer.

Preparation of fluorescent samples

Instructions for looking at some fluorescent samples, photo 4
1. Dissolve some highlighter ink in water
2. Tonic water
3. Vitamin B dissolved in water
4. Colour pages coloured in with regular and highlighter markers

Be creative, make a drawing or colour in a page from a colouring-book using standard colouring markers and fluorescent highlighters. Take a look at your drawing under the different types of illumination from the LED and the black light.

Step 5: End Result & Conclusion

What we learned?

By creating your own mini dark rooms and interrogating a range of different samples, you have the opportunity to learn about how colours and light are connected. You get to construct a simple electronic circuit that allows you to combine light sources and see how these combinations change what you observe in the experiments while also introducing you to electronics. The samples mentioned in this document are not meant to be limiting, and we certainly hope that further examples and samples are investigated based on your creativity when you try this at home. Although no directly 3-D printing, you can start to ask how were those components created and what else can made using this technology.

By using UV light to illustrate fluorescence and make the invisible visible on bank note, the concept of invisible information made visible by light is introduced. Using photonics to unlock secrets of our world is an exciting prospect and in some sense all scientists are detectives of the nature world, our workshop participants can take this feeling home with them!

Concluding thoughts

The spirit of scientific enquiry can be fostered by revealing knowledge previously hidden using the power of light! White light is not itself a single entity but is composed of a combination of different colors or wavelengths. The response of different colours to different illuminations brings questions about the nature of visible light and how we perceive the world.

This workshop serves as a primer to the amazing nature of photonics and its link to our perception of our environment every day, every colour can be measured and quantified giving us information about our world. When we isolate and focus on particular colour combinations, we learn more about their true nature.


PHABLABS 4.0 is a European project where two major trends are combined into one powerful and ambitious innovation pathway for digitization of European industry: On the one hand the growing awareness of photonics as an important innovation driver and a key enabling technology towards a better society, and on the other hand the exploding network of vibrant Fab Labs where next-generation practical skills-based learning using KETs is core but where photonics is currently lacking.

This workshop was set up by National University of Ireland, Galway, NUIG in close collaboration with Makerspace NUIG.