in this q a video we're going to answer the question why is it that led fittings rely on
red green and blue leds to make different colors instead of red yellow and blue
this question relates to our free training package to help with your cpd that we've made with bg
Luceco on the subject of smart homes systems it's completely free fully certificated by cpd uk you
can take it anytime and upon successful completion you'll receive a certificate and be able to count
an hour towards your annual cpd requirement you'll find this over on efixx.co.uk under the knowhow tab
or at lucecoacademy.com under the courses tab however, let's answer this question now looking
at the packaging for this smart light fitting you can see that you've got the letters r g b
on there now that stands for red green and blue and it means that the light source can be used to
create different colors by combining the output from red green and blue leds within the fitting
now it may seem a little odd that this is red green and blue and not the classic primary colours
red yellow and blue that we learnt at school as being the ones that make up all the other colors
now this is because as is often the case you only get half the story while you're at school red
yellow and blue are what's called a subtractive color model in other words the more you add
together the combinations of colors the darker the colour becomes i'm sure like me when you used to
combine all the colour paints at school you were kind of bemused by the greenish muddy mess that
you'd get only to go next door to your science class and be told that all the colours combined
together give you white well let's demonstrate what happens with these poster paints and this
canvas and I'm going to go into full bob ross the mode here hello and welcome to this episode of
the joy of electrical what we're going to be doing in this video is we're going to be looking at what
happens when we combine the primary colors red yellow and blue so we've got our happy little
colors on the palette here and we're going to be using these to create some artwork on the canvas
behind me what we're going to do we're going to start off with some royal red here so we'll get
this red look at that you just want to dab it on the brush there and you just want to then
gently stroke it under the canvas like that and you can see there we've got that
lovely bright red now what we don't want to do is start mixing up our colors straight away so what
we're going to do is we're going to take another brush we're going to take our jasmine yellow
and we're gonna get that really deep into the bristles and we're gonna create a new
patch of color there look at this look at that isn't that beautiful it just makes me happy just
seeing that on the screen there and that's the important thing to remember about painting is that
it doesn't matter what anyone thinks about it or what anybody does about it it's just about you
and enjoying yourself now we'll get some of this midnight blue here and there's our fourth square
there and those are our three primary colors as you can see aren't they beautiful don't they just
make you happy now we all know what happens when we start to combine these colors what we're going
to do is we're going to take our blue and our yellow and we're going to mix those together so
we'll take a little bit of the blue and we'll take a little bit of the yellow and then we're
going to mix them up real good there and you see what happens there look at that instantly
the color starts to get darker and you've got this this beautiful turquoisey green color right there
so we mix that up we mix that up real good and then we introduce that to the canvas and as you
can see we've got this beautiful deep green look at that beautiful color there deep green color
makes me happy makes me think of childhoods by the sea enjoying our youth but now look what happened
when we bring in the the red here as well so we'll get a big blob of the red and we'll mix that in
and look what happens now we get this absolutely hideous
brownish reddish mess here and when we whack that onto the canvas you can see
it's just got darker and darker and darker the more colors that we've combined and that's what we
mean by a subtractive color system it gets darker the more colors you add and it's nice to see
we've not made any mistakes on here because we don't have mistakes what we have are happy
little accidents now when it comes to lighting we use rgb or red green and blue and that's
what's referred to as an additive colour model which means that the more you mix them together
the lighter the colour gets let's demonstrate that here using these fittings from bg lucico okay so
we've set up the different lamps and fittings from bg lucico on the bench here and we've just wired
them up with some temporary connections and we're going to use these to demonstrate this principle
of an additive colour model using the red green and blue leds now it's really important to note
that each of these fittings can achieve that color changing effect by themselves with the red green
and blue leds that are inside them however here we're just using these as solid individual colors
to demonstrate the principle so what i'm going to do first of all is turn on the pendant style
lamp and that's giving off this bright red colour onto the surface of the canvas which i painted my
masterpiece on earlier you may remember now if i turn that one off and i bring up the
recessed style fitting that is purely green you can see there that's giving off this
really deep bright green color there you can see and now if i switch that one off
and bring up the blue light source you can see there that deep blue color there
however if i now bring the pendant back up you can see that the blue and the red light source when
the light combines and hits the surface creates this kind of purpley effect here and that's
because we've added those two colors together to create that slightly brighter color effect there
however if we now bring in the green light source as well you can see now we've created this white
light source here so those three lights combine their colors to give a white light and that is
the principle behind an additive colour model the reason that these two models behave differently is
that when you paint red yellow and blue colours onto a surface they absorb and reflect different
wavelengths of light the painted surface is not a light source in itself however when you turn on
a light with red green and blue leds inside it's actually giving off light so by turning the leds
up and down to different brightnesses you can get an almost endless variety of colors emanating from
the fitting so there we go simply put when adding colour to a surface we use a
subtractive colour model of red yellow and blue because the colours on the surface reflect and
absorb different wavelengths of light but when we adjust a light source to change the colour output
we use an additive colour model because the fitting is generating the light we see by for
more detailed information like this on different aspects of smart home systems please click the
link either in the description below or just head over to the know-how tab over at efix.co.uk
or lucicoacademy.com under the courses tab and as always we want to hear from you were you
aware that you'd been under-informed at school about colour models do you incorporate colour
changing led technology into your installations whatever the case please leave your thoughts and
questions in the comments section below and as always thank you very much for watching