View Full Version : Let's talk temperature

08-27-2001, 01:43 PM
Color temperature is relative to surrounding colors, so how is it that there are so many different ideas as to what the temperature of a particular color is or isn't. Let me restate my question......

What is the importance of temperature in the first place?

huhhhh.... I mean.... if you say that a green-blue color is warm because it contains yellow....then do you always have to think about that green-blue being a warm color.... I don't think so, but as you can see, I'm confused about the importance of knowing.

Again, what is the importance of temperature in the first place?

Help me understand. :(

08-28-2001, 04:38 AM
llis,,,,,you're overthinking.

color "temperature" means nothing. green is green, and red is red. it doesn't matter what TEMPERATURE they are. it will only cause confusion,,,,which is why you asked what the temperature of blue green is.

first of all,,,,,it doesn't matter. secondly,,,that the idea of blue green being warm because it has yellow in it only proves my point. just enjoy the expressiveness of color.....{M}

08-28-2001, 09:43 AM
Thanks Milt.....

You always come thru with the right words.

Keith Russell
08-28-2001, 05:34 PM

I thought 'colour-temperature' had to do with lighting. Don't astronomers base their estimates on the temperature at which stars burn, by the colour of the light the stars radiate?

'Daylight' (from our sun, on earth, on a cloudless day) has a colour temperature that is blue, and a certain number of degrees Kelvin. (Daylight colour-balanced bulbs give the same balance of 'colour' as sunlight, represented by a certain number of degrees Kelvin.)

I thought that this is what is meant by 'colour temperature'.

I didn't think it had anything to do with 'warm' or 'cool' colours...

...I could be wrong...


08-29-2001, 02:37 AM
When I took my first class after the 15 year layoff, the teach lined us up and asked what the temperatures of the colors in an outfit were.
I had a little nervous breakdown in art school over color theory and I agree with milt. Now that I am living it instead of trying to analyze it I get it.
The answer was "warmER than this and coolER than that"
It is a circle with tendencies to right or left. No hot, no cold, just warmER or coolER.
THAT'S my story and I am sticking to it!

09-01-2001, 10:56 AM
color temperature is relative. its just a way of describing color, like "light" or "transparent".

colors which are closer to red or orange on the spectrum are "warm", colors closer to blue on the spectrum are "cold". since the spectrum is continuous (circular?), these things can go either way.

a cold red is one that appears violet or bluish. a warm red is orange. a cold yellow is greenish, a warm yellow is orangey.

a phtalo turquoise could either be a cold green or a warm blue. cad yellow deep is a warm yellow, cad lemon is a cold yellow. manganese violet is a warm violet, dioxazine purple is a cold violet.

this is very hard to describe. does this help?

09-01-2001, 04:20 PM
Knowing about color temperature is important because it’s another tool you can use to your advantage in making your artwork sing. Contrast is so important in creating a focal point and directing the viewer’s attention through the painting. You can have contrast of value, edges, line, texture, color intensity, and color temperature.

Temperature is relative. You know that 80 degrees F. can feel pretty hot. But if you’ve been out in 100 degree weather with high humidity, and come into an air-conditioned room at 80 degrees, it feels pretty cool!

Same with color temperature. Most of the time, blues, greens and purples are cool. But there are some that can jump out at you and be hot!

You can figure out for yourself what’s what by putting colors next to each other and comparing. You will easily recognize that orange looks warmer than blue. It may not be quite as easy to recognize the difference between a warm purple and a cool purple, but if you put them side by side you will begin to see.

The exciting part is using the warm/cool contrast to jazz up your paintings. Color has some visual dynamics. Warmer colors tend to come forward and cooler colors recede. That is, an orange circle will seem closer and larger than a blue circle of the same size. You have noticed it in the mountains, as they are farther away they are more and more cool in color.

So if you have a focal point you want to punch, you can make it a warm or hot color and surround it with cool colors.

Color intensity plays a part in temperature, too. More intense colors appear warmer than muted or grayed colors.

Here are some pictures of a colored pencil sketch of mine that may help. The table top is pink. It has more yellow and orange in the pink in the part that appears closest to you. It has more purple and blue in the part that appears farther away.

There are some temperature contrasts in the sketch. See the difference in temperature on the light side and shadow side of the fruit. I tried to put cool background next to warm object, such as the blue wall behind the red apple. I also tried to put warms and cools together in the objects. See the close-up of the grapes for an example of this. Some red in the shadows makes the green grapes seem greener. Some of the greens are warm and some are cool.

To me, making use of color temperature gives a lot of life and atmosphere to a painting. That’s why it’s important to be aware of it.


09-02-2001, 09:31 PM
llis, I think colour temperature is important but you don't really need to intellectualise it as IMO it's one of those aspects of painting where feeling has as much, or more, to say.

Some facts about colour temperature first (snooze :)). Keith mentioned astronomy and this is a classic example of where facts get in the way. We all know the visible spectrum from mnemonics we learned in school - Richard Of York Gave Battle Vainly - red, orange, yellow, green, blue and violet. This is a small fraction of the electromagnetic spectrum with radio waves and infra-red below it and ultraviolet light, gamma- and x-rays above. So in actual fact red stars are coolest, blue and violet stars are hottest: doesn't really help does it?! Keith also talked about daylight which is 5000K and it is indeed bluish, particularly indirect northlight, because the atmosphere is best at scattering lower-energy photons (the red end of the spectrum). Early morning light is typically 3500K - lower in temperature but warmer to us, which is one reason for our emotional response to morning. Overcast skies are around 7000K (because of even more scattering) which again is hotter in real terms but cooler to us, hence warmer colours look so dull and people can feel depressed on rainy days and during the winter (and is directly responsible for SAD).

So our interpretations of colour temperature are quite complex and relate, I think, to our origins: it may be based on something as simple as fire being hot and ice being cold, which certainly makes sense. For us red, orange, yellow are hot and green, blue, violet are cool; for most people the hottest colour is an orange or a red and the coolest a blue.

I read a long time ago in an oil book that Cadmium Red Light is the hottest pigment (one of the reasons it is so often described as fiery) and for me this still holds true but I can't tell any more if this is because it is actually 'hotter' or just because I know it's supposed to be! As for which blue is coolest among paints this is open to interpretation. I have four blues and in masstone I would have to say Ultramarine looks coldest to me, despite the fact that intellectually I know this is a violet-biased blue and is by definition warmer than a neutral blue. It's possible this is because its value is slightly higher than Phthalo Blue so it is simply easier to see, so for this reason I mixed an equal volume of Titanium White into each of the four to see what the undercolour said when compared directly to its neighbour. Here I would say Cobalt Blue had the edge although I was surprised at how hard it was to decide - Phthalo Blue GS's cleaner tint may have been a factor here.

Knowing some of the properties of colour temperature certainly helps when one wants to manipulate things. Warm colours tend to come forward visually and cool colours to recede: this is again an interpretational thing and here I think it is based on atmospheric perspective - items appear lighter and bluer the farther away they are - and is one of those things we all learn fairly early on and everyone can appreciate. One can use this to deliberately push or pull pictorial elements to make them more or less visually important in an image, in addition to adjusting value and saturation - cooler shadows will recede more than warmer ones, warmer highlights will pop out more than cooler ones. Most talented figurative painters know this sort of thing, some without being able to explain it, they just know what works.

As you yourself said, colour temperature is relative, which is one of the things that makes it so exciting. Greens are a cool colour but are warmer than blues so in a restricted palette they can be the warm accents; ditto with violets. The reverse can be also used - in a warm painting greens or violets can be used as cool accents, it all depends on the amount of contrast one wants and the effect one wants to achieve. By the same token all oranges are hotter than all violets, all yellows are hotter than all greens and all reds are hotter than all blues. But it gets complex when one compares other colours - not all reds are hotter than all oranges, not all blues are cooler than all violets and so forth. And what about violets and greens compared, which is warmer? Here it is a matter of observation and deciding for oneself - all part of the fun of colour mixing :)


10-29-2001, 02:04 PM
I don’t know what the ‘importance’ of temperature is; that is very much a personal view. However an understanding of why human perception is shaped in such a way that knowing (to the degree that things can be ‘known’) why red is perceived as warm and blue as cold may help. Some reference was made to astronomy and it is a starting point and what follows is very general.
True enough infra-red is towards the ‘cold’ end of the electro-magnetic spectrum. Red stars are indeed colder. “But red is a warm colour!” I hear you say. Let’s look at that. Why do we perceive it as such? Well, a lot can be gleaned from the two terms sometimes used in colour analysis of both stars and the visible spectrum; Brightness and Luminosity. Luminosity is the rate of energy released by an astronomical body, in our case pigment or light. Brightness is the rate that energy is received by a detector, in our case the eye. Luminosity does not depend on the observer as it is a standard measure. Brightness does as it is a variable - an inverse square law. The lower temperature of Red thus emits lower energy. The higher temperature of Blue emits higher energy. Green is ‘cooler’ only because it is to the left, on a wavelength scale, of Yellow. However it is also below Yellow on the amplitude scale. Green appears harmonious and balanced because its amplitude AND wavelength are symmetrical. The brain tends to do that – balance information. Green thus has balanced Luminosity and Brightness. Red does not, nor does blue. Yellow is half way between Red and Violet on the wavelength scale but virtually opposite to both on the amplitude scale, hence its brightness. The electro-magnetic properties of light (luminosity in this case) cause an electro-chemical reaction to occur in the brain and body. The brain attempts to balance the information. Think of it as a see-saw that is 'off' centre. To compensate/balance for brightness it therefore requires MORE energy to balance the LESSER luminous property, Red. And LESS energy to balance the MORE luminous property, Blue. Thus Blue doesn’t need as much energy to balance your perceptions as much as Red. Thus it feels cooler as a colour. Less energy=less temperature.

Of what importance this may be is probably irrelevant. Mixing colours is supposed to be fun.



11-03-2001, 06:28 PM
No one has mentioned the other value (no pun intended) in understanding the temperature of colours - we perceive cool colours as further away and warm colours closer (something technical to do with our eyes focussing and where they hit on the retina or something). Hence you can use temperature to your advantage to pull a foreground closer with a touch of warmth or push a horizon away with bluey greys.

But I agree wtih teh others - I find the technical stuff fascinating but there's no need to overdo the facts and figures.