Related notes: Lighting, Unreal Light
Electrons back to lower energy state emit photons. Red light is low on energy.
Light Source
- Incandescence (Burning stuf) - black body radiation (temperature of matter) > hoter more energy > brighter higher intensity light.
- Luminescene - not produced by heat. (Gas (most not white) ??)
- chamical bonds. Tribo/chemi-Luminescence
- Electroluminescene - LED’s (less generation of heat)) (hard to find blue leds).
- Remittance
- Fluorescent - neon (discharged and pump high voltage (add flurecent to controll collor)) Gas discharged lamps (high pressure gas) product arc. (high voltage). Pump electircity throu filament
- Posphorecence (farba fluores…)
CRI -color rendering index (90)
CRI -outside 100
Fake spectrum in lightbumlbs to be able to see all colors .
Wavelengths
The Compton wavelength (scattering of photons by electrons) is a quantum mechanical property of a particle. equal to the wavelength of a photon whose energy is the same as the mass of that particle. (The energy hν of a photon of this wavelength is equal to the rest mass energy mc2 of an electron.)
measured distance in meter to nanometer
| . | ||
|---|---|---|
| Gamma | - 100 pm | Short wavelength |
| X-rays | 0.01 - 10 nm | So strong taht can go throu skin (~atom lvl) |
| Ultraviolet | 10 - 400 nm | much energy - not healthy (~molecule lvl) |
| Violet | 380 - 430 nm | Visible Spectrum Strong (can penetrate material more) |
| Indygo | Visible Spectrum | |
| Blue | 430 - 500 nm | Visible Spectrum |
| Cyan | 500 - 520 nm | Visible Spectrum |
| Green | 520 - 560 nm | Visible Spectrum |
| Yellow | 560 - 590 nm | Visible Spectrum |
| Orange | 590 - 625 nm | Visible Spectrum |
| Red | 625 - 740 nm | Visible Spectrum Weak (like penetration in material) |
| Infrared | 800 nm - 1 mm | TV remote controls |
| Microwave | 1 - 1000 mm (1m) | ?300 GHz - 300 MHz |
| Sound waves high end | 17 mm (20kH) | 5-20 kH ( speed 343 m/s ) |
| Sound waves medium | 300 Hz - 5kH | |
| Sound waves bass | 17 m (20Hz) | 20-300 Hz Bass |
| Radar | ||
| Radio AM | 535 - 1605 kHz Up to 1200 bits per second. | |
| Radio FM | 88 - 108 MHz 1200 to 2400 bits per second. | |
| Radio Wave | 1 mm and at 30 Hz is 10,000 km. | 1 mm = 300 GHz - 10,000 km = 30 Hz |
Light measurement
Square law - Intensity of light disappear with square of distance (cd) ∝ 1/square of the distance.
Measure
| Def | Term | Unit | - | |
|---|---|---|---|---|
| At the Source | Luminous Intensity | Candela (cd) | Direction | Light (measures the visible intensity from the light source) |
| Flow per Area | Luminous Flux | Lumen (lm = cd * sr) | Solid Angle | Directional Candela (Candela steradians) how much emited off in given angle |
| Bright on surface | Illuminance | Lux (lx = lm/m2) | Distance & od Incidence | how much on Material |
| total bright of Surface | Exitance | Lux (lx = lm/m2) | Material reflectance | (white-black) how bright will be a 1m^2 of your surface. |
| Surface specific | Luminance | Nit (cd/m2) | Material dir specular | white-mirror (5% of lx (lux)) |
| Surface specific | Luminescence | cold-body radiation |
Solid Angle
Steradian (sr) (square radian) SI unit of Solid Angle
1 (sr) Ω = A/r^2
- A = Area on surface
- r = radius of sphere
| Lights | Solid Angle | ||
|---|---|---|---|
| Full Sphere | 4π sr | 1 Candela light-source uniformly radiates in all directions a total luminous flux of exactly 4π Lumen | 1 cd * 4π sr = 4π cd⋅sr ≈ 12.57 lm |
| 1 sr (“cuts out” an area of 1) | across a solid angle of 1 sr | 1 Candela light-source uniformly across a solid angle of 1 Steradian, equal luminous flux emitted into that angle is 1 Lumen | 1 cd * 1 sr = 1 (lm) |
| Spot 44° | 1.76 sr |
For Unreal
| Lights | solid angle | 1 lm ≈ | 1 cd ≈ | |
|---|---|---|---|---|
| Point | 4π sr | 49.7 * (1 unitless) | 4 x 3.14 = 12.566 lm | |
| Spot | 2π * (1 - cos(θ)) | 99.5 / (1 - cos(θ)) * (1 unitless) | ||
| Spot 44° | 1.76 sr | 354 * (1 unitless) | 1.76 * (1 lm) | |
| Rect | 2π sr | 1.31 | 199 * (1 unitless) | 3.14 *(1 lm) |
Blackbody
Theoretical idea. Color temperature of a blackbody measured in Kelvin (K) How strongly we heat up object determine light colors super hot > blue
| Color Temp (K) | Descrip | RGB Linear color |
|---|---|---|
| 1700 | Match | (255, 51, 0) |
| 1850 | Candle | (255, 60, 0) |
| 1 800- 3100 | Sunset/Sunrise | (255, 60, 0) - (255, 130, 40) |
| 2400 | Incandescent lamp | |
| 2700-3000 | typical home light | |
| 3200 | Studio lamp | (255, 134, 46) |
| 3500 - 3600 | Golden Hour | (255, 149, 62) - (255, 152, 68) |
| 4000 | Fluorescent | (255, 170, 91) |
| 3500-5000 | Early Morning\Evening | (255, 149, 62) - (255, 204, 154) |
| 5000 | Horizon daylight | |
| 5500 | Typical for photography | |
| 6500 | Daylight, overcast | (255, 242, 246) |
| 6500 – 9500 | LCD or CRT screen | |
| 8000 | outdoor Shade | (200, 208, 255) |
| 15,000 – 27,000 | Clear blue poleward sky |
Luminous Flux
| Lux (lx) | Descrip |
|---|---|
| 30,000 - 120,000 | Sunlight Range |
| 111,000 | Bright Sunlight |
| 20,000 | Full Sunlight Shadow |
| 1,000 - 2,000 | Tv studio lighting / Midday Overcast |
| 400 | Clear Sunrise/Sunset |
| 250 - 500 | Office lighting |
| 150 | Trainstation platforms |
| 100 - 200 | Midday overcast Storm Clouds |
| 80 | office hallway / toilets |
| 40 | Sunrise / Sunset |
| 0.01 - 0.25 | Clear Night with Quarter Moon - Full Moon |
| 0.0001 - 0.0002 | Moonless Night Overcast - Clear |