The Joy of Hand-Held Spectrometers: Exploring the World of Light and Color

As I sit here with my trusty hand-held spectrometer, I am reminded of just how fascinating this gadget can be. Not only is it a tool for measuring the light spectrum emitted from various light sources or ambient light around us, but it also offers endless possibilities for experimentation and exploration. In this article, we'll delve into the world of light and color, exploring what makes this device so special and how it can be used in both practical and fun ways.

One of the most exciting features of my hand-held spectrometer is its ability to test out different light sources around the house. I love watching as the colors and intensities change depending on the source. For instance, taking a look at sunlight is a great starting point, as it's considered an ideal light source. But what exactly makes sunlight so special? The answer lies in the concept of a blackbody light spectrum. A blackbody is essentially a metal object that absorbs all wavelengths of visible light and emits them back out as heat. When heated up, the metal undergoes a transformation, shifting from a glowing orange to a brilliant white, and eventually to blue or white hot. The color temperature of a blackbody is measured in Kelvin, with lower temperatures resulting in warmer colors and higher temperatures producing bluer, whiter light.

So, what does this mean for us? Well, when looking at a light bulb box, it will often display the color temperature, which can range from warm to cool. Warm colors are generally associated with incandescent bulbs, while cooler colors indicate LED or other types of lighting. However, not all light sources are ideal, and that's where my hand-held spectrometer comes in handy. Take, for example, a daylight-balanced LED bulb, which is designed to mimic the brightness of sunlight at its peak outside. Upon closer inspection, we can see that this bulb has a pronounced blue spike, giving it a whiter, bluer appearance. In contrast, warm-colored LEDs, like those with a 2700K rating, have much less blue in their spectrum, producing a warmer orange glow.

But what about incandescent bulbs? These, too, exhibit an ideal spectrum, mirroring the naturally occurring colors of a blackbody radiator. When looking at an actual incandescent light, we can see that its spectrum is smooth and continuous, providing a high quality of light. This is in stark contrast to other types of lighting, which may have a more pronounced spike or be less balanced overall.

Now, I know what you're thinking: "So, how does the quality of light affect our perception?" Ah, my friends, it's quite fascinating! The color temperature and spectrum of light can indeed influence how we perceive colors in real life. For instance, if you were to look at a color through an incandescent light versus an LED bulb, you might notice subtle differences in hue and saturation. This is because our brains are wired to respond differently to various wavelengths of light.

To illustrate this point, I'd like to share a cool example from my experience with Philips Hue bulbs. These RGB bulbs can be programmed to produce any color or shade, but when set to just blue, they exhibit a pronounced spike in that particular wavelength. When I shift the color to red or green, I get spikes on those colors as well. However, when I set it to yellow, the result is a beautiful combination of green and red spikes – a truly mesmerizing effect! This demonstrates just how nuanced our perception of light can be, depending on the source.

Of course, my hand-held spectrometer isn't just for show; it's also a powerful tool for measuring various parameters related to lighting. In addition to showing graphed spectra, this device can provide an array of other values, each with its own purpose and application. Whether you're looking to optimize your light bulb selection or simply appreciate the beauty of light in all its forms, my hand-held spectrometer is an essential companion on any journey of discovery.

As I wrap up this article, I hope I've inspired you to explore the world of light and color with me. With a hand-held spectrometer by our side, we can unlock secrets hidden within the electromagnetic spectrum and appreciate the intricate dance of wavelengths that surround us every day.

"WEBVTTKind: captionsLanguage: enThis right here is a hand-held spectrometer.It's one of my favorite gadgets that I own,and it's used to measure the light spectrumemitted from light sources or just the ambientlight around you.So in addition to this video just being aboutthis cool gadget in general, how it works,what it's for, I'm also going to be doingsome cool experiments, I think, such as testingout these blue light blocker glasses, howwell they really work.And I'll also talk about some practical informationand tips about lighting in general that youcan use when you go to buy your next set oflight bulbs or whatever, because this canalso actually tell you the quality of thelight.Yes, that is a thing.And I'll go over how that works.Alright so let's talk about some actual usesof this thing.And probably the most fun feature I thinkis the ability to test out what the lightspectrum is for different light sources aroundthe house.And here are some examples.So first we can look at sunlight because sunlightis considered an ideal light source.But what exactly is an ideal light source?Well, they basically look at what color isemitted when you heat up metal, for example.So you know how when you heat up a metal thing,it first turns like a glowing orange, thenit becomes more and more white.And that is called a blackbody light spectrumbecause it's something that is like a blackmetal, and as you heat it up, it goes fromblack to white and eventually blue or whitehot.And as it progresses, getting hotter and hotter,which actually is measured in Kelvin, it thenis going to emit a light spectrum for thatparticular temperature.And then what that spectrum looks like isthe color temperature.So that's why if you look at a light bulbbox, it'll tell you the color temperature,whereas the lower the temperature, it's goingto look more orange, and the brighter it'sgoing to look more blue and white.But not all light sources are ideal.So here's an example of a daylight balancedLED bulb, which is balanced for 6500 K, whichshould look like sunlight at its brightestoutside.And you can see it looks a lot different thansunlight.There is actually a big blue spike which kindof gives it that whiter, bluer color.And then of course, there is the other colorsmixed in.And you can see if we look at a warm colorLED of course, it's going to have a lot lessblue in it.Now, these LEDs, I believe, are balanced for2700K, which is a very warm orange light.And of course, this is not an ideal spectrum.But if we do look at an actual incandescentlight, which basically is a blackbody radiator,so this will produce a ideal spectrum at thistemperature which looks like this.And you can see that a naturally producedspectrum is going to look way more smoothand continuous.So this is going to have a better qualityof light, you would say.And I'll go over all that later, though.Because minor spoiler, yes, the quality ofthe light and the spectrum actually can affecthow things look in real life or how they appear,compared to if you did look at it throughan ideal light source, like an incandescentor outside.Here's kind of a cool example.If we do Philips Hue bulbs, which are ourRGB bulbs, if we set it to just be blue, ofcourse there's a big blue spike.And if we set it to red or green, again, it'sgoing to have spikes on those colors.But if we set it to yellow, for example, it'sgoing to have a combination of green and redspikes.So that is kind of cool.Now, in addition to showing you just a graphof the light spectrum, this device can alsoshow you a whole bunch of different valuesof different purposes.Now you're probably thinking, \"Oh what inGod's name are all these?\"Don't worry, you don't have to know what allthese are for, not going to go over all ofthem.And if you're curious, though, I will puta chart for the names of all these values,maybe if you want to look it up at some point.But basically a lot of these values are usefulfor in filmmaking and videography purposes.Getting the light colors correct, and alsoagain measuring the light quality, which I'llgo over later.So all of that is very neat,but why did you even buy this?How is this actually useful?And like I said, I mostly bought it for thevideo making purposes.And specifically that is going to mean gettingaccurate colors on the lights that I'm using.So for like skin tones, so I don't look extrared or something like that and also gettingconsistent color, I can use the measurementsto match up the light sources, because eachlight source, even if it's like the same brandsame model, they're going to be slightly differentfrom each other.So I can use that to match them up by changingsome of the settings.So let me show you a real life example ofdoing this.So if I wanted to set the color temperatureon my lights, these ones are kind of fancy,they actually do let you set a color temperaturejust by turning a dial.But how do I know that that's actually thecorrect ideal temperature for what it's supposedto be, likeif I set the camera to match that color temperature,maybe it is a little bit off.Or maybe if I set one light again to thatcolor temperature, it might not be the sameon the other one, even though the number'sthe same.And actually you can see that is exactly thecase.If I set both of these to say, 5000 Kelvin,then they're not exactly at 5000 Kelvin andeach one is a little bit different.It might not be enough to notice, but if youreally want to be 100% accurate, then thisis what you would use.But color temperature is not actually thewhole story, because it could also have acolor cast of magenta or green.I'm not going to get into why those particularcolors are the ones you have to worry about,but it is.So this meter can actually tell you how muchof a slight color cast it might have, andtherefore how much you have to adjust thelight by, to get it back correct.Now, like I said, these lights are prettyfancy and fortunately this actually literallylets you adjust a dial to increase and decreasethe magenta-green levels.But you can also do it the old fashioned way,which is to just overlay a so-called gel orbasically a filter over the light source tokind of cancel out some of that magenta orgreen.And here's actually a fun fact.A lot of times office buildings will use fluorescentlight bulbs, which have a green color castjust because of the spectrum, the chemicalsbeing used in the light.And you have to adjust for that if you wantto get a correct color, if you're doing video.So to adjust for that, to cancel out the green,you would use the opposite, which is a magentafilter.You'd literally just put it in front of thelight.So to avoid any confusion, these filters arenot usually called magenta filters.They're called \"minus green\" filters.Because otherwise, if you called it a magentafilter, people might think, Wait, does thatmean that the filter itself looks magenta,or it filters out magenta, which means itwould look green.So that name removes the ambiguity and it'sjust called minus green.If you want to get rid of green, you buy aminus green filter.Now speaking of filters, another really coolthing this device can do is, it has a bunchof filter brands plugged in.So for video making, there's a bunch of manufacturersthat make minus green filters and it has theseplugged in.So you can actually use this on a light sourceand it will tell you the closest brand andmodel of filter that you would need to getto correctly correct for whatever color castyou have.So that's just another thing built in in termsof videography features.So next up, let's do something a little bitfun.So I bought a bunch of these different blueblocking glasses of different strengths andwe can actually test out exactly what theydo and what they look like on the light spectrumwhen you look through them.And there are different strengths of these,obviously, that you can buy.For example, these ones are supposedly goingto block all blue light, effectively.And this is something you would use at night.Like if you want to help with your sleep,you might know that blue light tends to messwith your circadian rhythm and keeps you uplater.So if you wear this at night, then this couldhelp out by reducing that blue part of thespectrum.There's also these more lighter ones whichdon't block out all the blue light, but mightblock out a good amount.These are usually advertised as like computerglasses.They can help reduce eyestrain supposedly,that sort of thing.And then there are even those that almostlook completely clear and they're actuallyadvertised as having a clear lens.So do these actually work, especially theseones?That's kind of what I wanted to find out andthe results are kind of interesting.So the three different types I bought, thefirst one is this cheapo \"Livho\" brand advertisedas having clear lenses.This is the one I was actually really skepticalabout because on the pictures it looked likeit was not tinted at all.And it's like $15 for a two pack, I thoughtthis might be some kind of scam, so I wantedto test.I also bought Gunner Optiks, these are likea more expensive brand.This was like 45 bucks, and this is the Ambertint of glasses.They also do make a clear one, this is thesecond weakest strength.So it goes clear, amber, and then there'stwo other stronger ones.And then these are Spectra brand blue blockers.And these are advertised to block basicallyall blue light virtually, and even some inthe green spectrum, so we can test that out.And basically I did two different tests foreach, for two different light sources.One was sunlight, and then another one wasmy monitor set with a just white screen.And then I did a before and after with theglasses in front of the sensor, and then not.Now first we have this cheapo Livho brand,and like I said, I was skeptical about thisone because the pictures look like it hasno tint.They also include this test card, which supposedlyshows you how the glasses block \"harmful bluelight\", they say.But this is clearly just a UV light sensitivetest card, and this is clearly a UV flashlight.And actually, if we look at the light throughthe meter, it actually does show that it'ssmack dab in the middle, 400 nanometers, whichis like the edge of ultraviolet.So, yeah, this is not a blue light test card.It's a ultraviolet light test card.So I was kind of thinking, all right, thismight be a scam, actually, but if you do putthese on, they do have an ever-so-slight yellowtint, so we'll have to test it further.So this is the spectrum of direct sunlight,and now we can compare it to through the glasses.And in this comparison, the yellow line isthe original sunlight, and then the coloredspectrum is what is through the glasses.So right off the bat we can see it blocksUV light, which starts at around 400 nanometers.So the part about blocking UV light is correct,but it only slightly reduces the blue onlya little bit.So next we can test with the computer screen.This is what it looks like.No glass or anything, just right on the screen.And it's interesting, you can actually seethe three different colored peaks for theRGB.And again, we can see that it does slightlyreduce the blue, although it kind of reducesit across the board, but slightly more inthe blue.But subjectively though, do these actuallywork?Well, I think it depends on the use case.So if you're just purely using this to tryand reduce eye strain while maybe lookingat a computer, maybe it would help.So for example, I have this TN panel thatI am using while I have my IPS monitor outfor repair.And this thing like sears my eyes, it's sobright, so blue shifted.And when I put it on, it does ever so slightlyI think, take the edge off the bright bluenessof it.So there are also have been reviews I readon the Amazon page, and people did say itkind of reduced the eyestrain, so that mightbe useful, just taking the edge off some ofthe blue light.But I definitely wouldn't really considerthese like blue blocking glasses.And it says it blocks the \"harmful blue light\",although that's mostly just the UV and likea little bit of the blue.If you want to really reduce the blue lightyou're seeing, you're going to have to gowith something that actually looks yellow.If it doesn't look yellow in the lens,then it's not going to be canceling out anyblue-ness.And by the way, that's going to apply to anybrand of glasses that have a \"clear\" typeblue blocking lens.It's only going to block a very slight amountof blue.So if you're going to be using these for likesleep to reduce blue light, it's not goingto work at all, or at least a negligibleamount.Now let's take a look at these Gunnar Optiksones.And these are going to obviously have a morestronger result because you can visibly seethat they are yellow.And here's the results for sunlight for these.And right off the bat, you can see that thereis a much more noticeable difference.So it reduces more blue light at more wavelengthsof blue and by a larger amount than the clearones.So that shouldn't be a surprise.Now, when we look at the monitor, though,it actually kind of was surprising becauseit looks like there's a way bigger differencein this situation, though.That could be because the blue spike in generalis just bigger.And in terms of subjectively using these,I did get the aviator ones because it coversmore of your visual field, I think.And this one obviously is much more noticeablewhen you put these on.And I definitely think these actually do reducethe harshness of at least the monitor I'musing.So if you do have a big bright monitor thatyou think is kind of annoying to look at,then something like this I probably wouldrecommend.There's definitely cheaper options than GunnerOptiks, so you can maybe look into those.But there are also software solutions thatI can mention in a minute.All right now we can look at what I thinkis the most interesting one.This one supposedly blocks all blue light,or at least like 99.9% of it.And you can see these literally look orange,so this one should be interesting.So again, here's what sunlight looks likenormally.And here it is through the glasses.Wow.I think it's safe to say that it does workas advertised, it's just flat lined on theblue, and it even cuts down a vast majorityof the green as well.And it shows on the page that I think it'ssupposed to block out 80% of green, so thatseems to be true.And if we look at the test with the monitor,here's before, and then after and yep, samestory, all the blue is gone.And these are actually kind of interestingbecause if you have any devices around thehouse that have a pure blue led, when youwear these, it just looks like it's off completely,the light.So that's just kind of interesting.And when looking at monitors, another thingto note is that because monitors have RGBsubpixels, if you look at something that'skind of a mixed color, it will often makeit look green because it reduces the greenbut doesn't completely eliminate it like theblue.So some things will go from looking kind ofbluish to green.And then of course, the red ones still show.Now, all this being said, you actually needto go and buy computer glasses.Probably not.Now, if you want to use these for like sleepaid purposes or whatever at night, then yeah,you would actually have to go buy true blueblocker glasses, and you have to get themthe blocks all blue light like these.And these are ones I actually use,so I'll put the link in the description, Iwould recommend these.But if you just want to reduce some of theblue light on your computer, there is actuallya software solution called Flux.I've recommended this for years, and it basicallyjust changes the color of the screen to reduceblue light, look more orange and it's free.And you can crank this down pretty much aslow as you want to reduce as much blue asyou want.And you can see that it really does get thatblue light way down.So that might be something to try first.Or you can just do it a little bit, again,just to maybe take the edge off.All right so moving on, we can now talk aboutthe topic of light color quality, which Iactually think is really interesting.Now in general, the quality of light, you'rebasically going to be comparing it to a blackbodylight source.So that would be daylight at like 5500K or6500K or an incandescent light at 2700K.And again, this is what daylight looks like.This is what a incandescent light bulb lookslike.You can see they're mostly continuous, thelight bulb more so.But the daylight still kind of there's nospikes or anything.Now, at this point, you might be thinking,\"now, what are you talking about?The light quality from a light bulb.Every light bulb I've ever bought looks fine\".And that's because our brains do a reallygood job of adjusting to light.So yeah, for 99% of time, it's not reallygoing to make a difference.And that's why if you use really warm lightbulbs, 2700K, then if you're looking at stuff,you can still easily tell what color it isand how the color compares to another colorin that light.It's not like if we're inside with a warmercolor light bulb that everything literallylooks orange, our brain adjusts for it, soit doesn't matter.And of course we can do the same thing ifwe're outside.And that also applies to maybe not-ideal lightsources that have kind of spiky spectrums,our brain mostly just for it.But if you want to take the red pill of lightbulbs, I can tell you that most light bulbsactually do not reflect the real color ofthings when you're looking at it.So what you might be seeing might actuallybe slightly wrong.Now again, it's going to look close enoughwhere most people, vast majority of peopleare not going to notice, unless maybe theychanged it to an ideal light source.And this might make a difference if you havelike nice paintings on the wall or something,or nice photographs.Then it is very possible that with a higherquality of light, that painting or whateveris going to look better, or at least closerto what the artist intended.And yes, of course, I will talk about howyou can tell how good the light is in a second.But first, if you're still not sure what I'mtalking about or you're skeptical, let megive you an extreme example to show my point.Take for example those yellow street lightsyou may have seen in the past, not so muchanymore,they're more LEDs.But you used to see these yellow street lightsthat were actually called low pressure sodiumlamps.And this has a very funny looking spectrum.It's literally just yellow, a narrow spikeof yellow.And if you look at this picture of two carsunder this type of light, you might think,\"all right they look like they're both black,right?\"But actually, the one on the left is brightred, and the one on the right is actuallyblack.But they both look black in this picture.And that's because the reason that car isgoing to look red in regular light in thefirst place, is because the paint absorbsall colors that are not red and then reflectsonly the red light back to you,and that's why you see it as red.So since there is no red wavelengths in thislight source, it's just yellow, then thatyellow wavelength is going to be absorbedby the paint just as it normally is.And since there's no red wavelengths to bereflected, then it's just going look black,there's nothing coming off it.So if you imagine this on a way less extremelevel, then you can see how if you have alight bulb that is producing too much or toolittle of certain wavelengths, then that inturn is going to mean it's going to reflectoff objects too much or too little of certainwavelengths.And then it's not going tolook correct technically.So what do we actually use to measure andrepresent the light quality of a light bulbor light source?Well, the general term is the Color RenderingIndex, and this actually uses a bunch of differentsampled colors that are kind of standardized,and these are test color samples, TCS.And there are different values that are \"R\"values with a number, and each color sampleis assigned to one of these \"R\" value numbers.And the higher the R-value means the moreaccurate that light is emitting that particularcolor.And it goes from 0 to 100.Now, there is one thing that's a little bitconfusing.There is a overall term for one combined ratingthat is often used, and that is also calledColor Rendering Index or CRI.So Color Rendering Index, usually when yousee it, it's referring to a combined valuewhich takes into account the first eight Rvalues, so R1 through R8.And usually on light bulbs and stuff, youwill see, it'll say CRI 95 or CRI 80.And that is basically saying how good thefirst eight colors are and just kind of usingthat as a general representation of the qualityof the light.And this combined rating is also called Ra.So if you are out shopping for light bulbs,you can look to see if it has a CRI rating.And basically anything above 80 is considereddecent.It's, you know, good enough, passable.Anything above 90 is good, and anything above95 is excellent.However, this CRI rating is not actually perfectbecause like you probably saw, there's waymore color sample possibilities.This literally only uses the first eight.And actually does not use some important colorsamples such as R9, R13 and R15.The R9 is red, and the other ones are moreskin tone color.But all of these are important for renderingcorrect skin tones.So it is possible for manufacturers to kindof game the rating where it might have a reallygood CRI because the first eight colors areright, but then the rest of them might suck,but it's still going to have a high CRI rating.But there is another better newer rating calledTM-30.Although you don't really see this very often,but I still want to talk about it.Unlike CRI, which only uses eight color samples,this one actually uses 99 color samples.And instead of being represented as just onebasic number as the quality, it actually showsyou way more information for this rating,because you can show it as a circle.And how you actually read this is, each pointon this circle is basically a sub-selectionof all the 99 colors or like combination ofthem.And if the circle of the light source is outsidethe ideal circle, that means that particularcolor is oversaturated.If it's inside the circle, it means is undersaturated compared to the ideal light source.And those little arrows also show how far-offthe hue is for that color.So the more the arrow points sideways, thatshows there is a hue shift and the color iswrong, like number 11.And if it points inward or outward, that showsthe saturation is wrong, like number 1.But it could be both, like number 15 lookspretty far off for both.So unlike CRI, which just gives you one simplenumber, this one actually shows you whichcolors are not as good or better and how.Now there is an average number rating thatyou can get with this TM-30 system, althoughyou actually get two of them.So one of them is Rf, which is the fidelityindex.This basically is the \"sameness\" of the colorsoverall, so you might say this is how thehue of the color compares to what it's supposedto be.And then also there is the Rg, which is theGamut Index, which is how much that particularcolor is saturated compared to how it's supposedto be.So you kind of get a little bit more information,well, a lot more if you're looking at thecircle chart.And that might help you make a decision onwhich ones you want to get depending on thepurpose.Unfortunately, it's not very common to seethis TM-30 rating, most still use the CRInumber.But again, if you're just using this for houselighting and stuff, the CRI is definitelygoing to be enough.And again, over 95 is excellent, 90 is goodand above 80 is like acceptable.But if you are trying to look up like videolights or something, you're going to be usingprofessionally, or you want the highest quality.Then definitely look for ones that might havea TM-30 rating, or see if you can find someonewho rates it themselves.All right, so I know we went over a lot inthis video.If you enjoyed the video, let me know whatyou think down the comments, give it a thumbsup.And also maybe consider checking out the restof my channel, maybe take a look at some ofthe videos I've made and see if you want tosubscribe and if you do also click the bellnext to the subscribe button to enable notifications,so the videos don't get lost in the rest ofyour subscription feed.If you want to keep watching, the next videoI'd recommend is another gadget video whereI talked about a microphone that is an ultrasoundmicrophone.It can record up to 100 KHz way more thanwhat we can hear as humans.And then I test some ultrasonic devices tosee what they would like if we couldhear them.Really cool, I'll put that video right there.So thanks so much for watching guys, and I'llsee you in the next one.\n"