Introduction
Through this experiment, we will be quantifying the effect of tungsten illumination. We will see if we can create any model which can measure the amount of broader spectrum incandescent illumination required in addition to low-pressure Sodium to obtain normal color perception.
The astronomer-friendly lightning, which is Low-Pressure Sodium (LPS) vapor, is very efficient and environment-friendly but produces poor image synthesis of illuminated lights because of its narrowband emission.
Basic Building Concept
1. Sodium Vapour lamp is a kind of lamp in which sodium is used in an excited state to produce light of wavelength 589 nanometers.
2. It is of two types:
- Low-pressure sodium vapor
- High-pressure sodium vapor
3. Low-Pressure Sodium vapor lamp is an efficient lighting source. It produces monochromatic yellow light, which restricts its application but it is highly used for astronomical purposes.
4. High-Pressure Sodium vapor lamp produces a broader spectrum of light than Low-Pressure Sodium vapor, but it still produces poor color rendering than other light sources.
Aim
To create a model for measuring the amount of broader spectrum incandescent illumination required in addition to Low-Pressure Sodium to obtain normal color perception.
Requirements
1. Computer
2. Digital Camera
3. Six Newtonian Targets
4. LPS Vapor Lamp
6. A Dimmer
Theory
1. Low-Pressure Sodium Vapour lamp is an efficient lighting source. It produces monochromatic yellow light, which restricts its application but it is highly used for astronomical purposes.
2. Tungsten illumination is incandescent that uses pressurized halogen gas for illuminating light. It works like another lighting source.
The Low-Pressure Sodium Vapor
Procedure
Step 1: Create six Newtonian color targets and illuminate them by 43000 lux from an eighteen-watt LPS lamp and by variable lux ranging from 0 to 3080 lux with a hundred-watt tungsten lamp.
Step 2: Regulate them with a dimmer.
Step 3: Click over 600 pictures of those targets and measure them photometrically.
Step 4: Now, you need to develop a program for converting RGB pixel data of each picture into CIE L*b*c values and for measuring delta E color variance against a hundred percent color reference by using a C++ programming language.
Step 5: Based on the average of delta Es of the Newtonian spectrum, make a Color Rendering Value (CVR) for each sample ranging from 0 to 100.
Step 6: Now, find out the average value of CRV’s sample and make its graph to find out an equation that relates the tungsten percentage and CRV.
Observation
1. We have observed that the LPS lightning is greater by 26%.
2. Tungsten lightning synthesizes images with near-normal color perception.
3. We can obtain higher standards by illuminating a higher amount of tungsten lightening.
4. LPS combined with broader spectrum illumination, like tungsten illumination, can prove to be an alternative for outdoor lighting. This is environment friendly and also cost-effective.
Result
1. The CRV
- for 2.5% illumination was 2.3
- for 15.0%, it was 3.4
- for 26.0%, it was 13.7
- for 35.9%, it was 30.1
- for 42.7%, it was 41.2
2. An equation that relates tungsten percentage W to color perception indexed by Color Rendering Value is
CRV = 38arctan (0.07W – 3.2) + 49.5
Precaution
1. Make sure the program is working properly.
2. Pictures should be taken clearly.
3. Camera should be clean before clicking pictures.
Conclusion
In this experiment for quantifying the effect of tungsten illumination, we have examined the effect of the illumination of tungsten on the color rendering of LPS vapor light with the help of a program that can analyze CCD pixel data and also derived a formula that relates color rendering and tungsten percentage.
VIVA Questions With Answers
Q.1 What was the aim of your experiment?
ANS. Quantifying the effect of tungsten illumination to create a model for measuring the amount of broader spectrum incandescent illumination required in addition to Low-Pressure Sodium to obtain normal color perception.
Q.2 What do you understand about sodium vapor lamps?
ANS. A sodium Vapour lamp is a kind of lamp in which sodium is used in an excited state to produce light of wavelength 589 nanometers.
Q.3 How many types of sodium vapor lamps are there?
ANS. It has two types- a) low-pressure sodium vapor and b) high-pressure sodium vapor.
Q.4 What do you understand about low-pressure sodium vapor lamps?
ANS. A low-Pressure Sodium Vapour lamp is an efficient lighting source. It produces monochromatic yellow light, which restricts its application but it is highly used for astronomical purposes.
Q.5 What do you understand about high-pressure sodium vapor lamps?
ANS. High-Pressure Sodium vapor lamps produce a broader spectrum of light than Low-Pressure Sodium vapor, but it still produces a poor color rendering than other light sources.
Q.6 What mathematical equation have you derived from this experiment?
ANS. CRV = 38 arctan (0.07W – 3.2) + 49.5
Q.7 What is the use of this equation?
ANS. This equation relates tungsten percentage W to color perception indexed by Colour Rendering Value.
Q.8 What do you understand about tungsten illumination?
ANS. Tungsten illumination is incandescent that uses pressurized halogen gas for illuminating light. It works like other lighting sources.
Saquib Siddiqui is a Mechanical Engineer and a content creator. He has special interest in science experiments and teaches the same to school and college students. He is also a technical lead at RUDE LABS PVT. LTD.
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