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Author Topic: Pigment Exercises  (Read 2873 times)

bottleman

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on: November 18, 2010, 09:42:47 PM
When studying the colour wheel, one potential problem, or even surprise, is that you might not have a pure primary colour in your paint box!  The popular Ultramarine Blue, for example, actually learns towards violet; it's a "warm" blue.  Phthalo Blue leans towards green, making it a "cold" blue.  You don't have to run back to your local paint shop.  Instead, a simple exercise will help you learn exactly what colours you have.

For acrylics and watercolours, a page in a sketchbook will suffice.  Oil painters will have to prepare a piece of cardboard or paper with Gesso.  Using a palette knife or brush, cover an area of about 1 square inch with paint directly from the tube.  Below, write down the exact name of that colour.  Now create a mixture of one half that colour, and one half white, and apply it next to the dab of pure paint.  For watercolourists, the paper will be your white, so a thinned out tube colour will be used.

White paint is the ultimate identifier of other pigments. Compare the diluted sample with the original; is the colour warmer or colder than you thought?  The pigment's tinting strength will also be revealed.  You may find that most yellows weaken quickly, while most blues remain strong.  The attached photo is from my own comparison of Phthalo and Ultramarine Blue.

It should be noted that there is a theory, usually referred to as the split primary palette, that claims primary colours do not exist, strictly from the point of view of available pigments.  The solution is to have two of each: a cold yellow and a warm yellow, a cold red and a warm red, ect.


nolan

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Reply #1 on: November 19, 2010, 03:12:22 AM
here is my split primary palette I use



Val

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Reply #2 on: November 19, 2010, 03:56:24 AM
 :confused: I think this may help with my limited colour palette but I need a little more clarification on how this works.  :help:
Cheers, Val

”Creativity is allowing yourselves to make mistakes. Work on knowing which ones to keep!”

- Alvaro Castagnet


Kelley

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Reply #3 on: November 19, 2010, 07:39:17 AM
 :coffee: Interesting and useful reading.  I understand that bringing the white (to lighten) the colour makes it more apparent where on the wheel the pigment leans toward.  The pthalo blue leans toward green vs. ultramarine blue having reddish pigment mixed in to lean toward violet.  It didn't occur to me that there would be such differences.  Thanks for the tip Bottleman.
Kelley


nolan

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Reply #4 on: November 19, 2010, 01:22:24 PM
Val the idea is that if you want to mix an orange, then you will use Cad yellow and Cad red because they are the two warm primaries, ie. next to each other. If you are looking for a green, you will use Lemon Yellow and Pthalo Blue as green is a cold colour and they are your two cold primaries.

This way you keep your colours as intense / pure as possible - the Chroma component of your colour.

eg if you use cad yellow and pthalo blue to mix the green, it will be less pure, read more grey / lower chroma as the cad yellow had a red component to it and red is the opposite colour of the green you are trying to mix, so you are lowering the chroma of the colour by adding the opposite colour to your green mixture.

The split primary colour wheel helps you when you want to mix high chroma colours, but most of the time it isn't necessary to worry about using the split primary wheel as very few colours, in nature at least, are in fact high chroma. They usually have a lower chroma (have a bit of the opposite colour in them).

It's great to know this principle though as sometimes you just can't get to the bright / vibrant colour you require, then chances are you are mixing a cold primary into a warm primary


bottleman

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Reply #5 on: November 19, 2010, 06:08:16 PM
nolan, that's exactly my split primary palette, although in recent times, I've changed the Alizarin Crimson to Cadmium Red Deep.

Val, I can't add to nolan's post, except to say that I think these exercises, and discussion of the split primary palette, put focus on the actual paints & pigments we have.


nolan

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Reply #6 on: November 19, 2010, 09:05:38 PM
Colour mixing is such a "sensitive" subject because everybody has their own "secret recipe", including myself, that works for them. All are similar, yet so different. That is why in the colour mixing section of the Perfect Painting course I tell everybody to try a few and find one that works for them.

Even my own palette of favourite colours "improves" every now and again as I learn new things and try new paint colours.


Val

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Reply #7 on: November 20, 2010, 05:09:07 AM
 :help:  :confused: OK... is there a set rule as to which red, blue, yellow one should start with on their primary colour wheel? How do I know which ones are pure? As an example, here are the colours I was able to find:.

Blues: Phthalo Blue, Ultramarine, Cobalt Blue, Cerulean Blue

Yellows: Lemon Yellow, Medium Yellow, Yellow Ochre, Deep Yellow

Reds: Rose Madder, Brilliant Red, Crimson

Which  3 would be a good combination to start my colour wheel?
 
I'm having trouble trying to decipher what makes a warm yellow compared to a cool yellow as exmaple. I've never had colour theory, is there an article or book you could recommend to help me wade through?
Cheers, Val

”Creativity is allowing yourselves to make mistakes. Work on knowing which ones to keep!”

- Alvaro Castagnet


Kelley

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Reply #8 on: November 20, 2010, 08:08:31 AM
It is difficult to see, but it appears that there is a "C" for cool and "W" for warm on the posted colour wheel. If this is the case, I noticed that Alizarin Crimson is on the left with the warm and French Ultramarine is on the right with the cool. Is this deliberate? :confused:
Kelley


bottleman

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Reply #9 on: November 20, 2010, 02:50:05 PM
Val - For me, the point is not so much about colour theory; a yellow is still a yellow. Is there a perfect set of pigments to represent the primaries? I don't know. Is there an imperfect set? I don't know that either. Instead, it's about looking at the pigments you have. Since you're asking questions, and listing paints, you're doing exactly what's right. So, let's take a look:

Phthalo Blue - definitely a blue that leans a bit towards green, making it colder

Ultramarine - leans towards violet, so a bit warmer

Cobalt Blue - probably the closest to primary blue, although it still might lean either way

Cerulean Blue - leans towards green

Yellow Ochre - more of an "earth colour" that usually leans towards orange. Good to have, but not as a primary substitute.

Now, the rest of the paints on your list use generic names that the manufacturer decided on. For example, had they named it "Dull" Red as opposed to "Brilliant" Red, think you would have still bought it?  ;)  That being said:

Lemon Yellow - almost certainly a cool yellow, leaning towards green

Medium & Deep Yellow - probably leaning towards orange

Brilliant Red - towards orange?

Rose Madder & Crimson - probably leaning towards violet

No question it can be difficult to truly identify every paint out there. Put dabs of each yellow in your sketchbook, and compare them very carefully. What makes them different? Doesn't one seem just a bit cooler than the other? Which one would you use when mixing an orange?

Kelley - I don't think nolan meant for that particular wheel to split down the middle, unlike in his colour wheel video tutorial.  It's really just to show that each primary can have two sides, strictly from a pigment/paint point of view.
« Last Edit: November 20, 2010, 02:58:54 PM by bottleman »


nolan

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Reply #10 on: November 20, 2010, 02:53:53 PM
Yes the w and c = cold and warm. The bottom w and c just work out so they are "opposites", but they match because you will find that french ultramarine has red in it and crimson has blue in it, so they work together.

Val from the paints you have, you can use :

cold yellow: lemon yellow
warm yellow: deep yellow, possible even medium yellow
yellow ochre is basically yellow with purple (opposite) in it already

cold red: crimson
warm red: brilliant red

cold blue: pthalo blue or cobalt or cerulean
warm blue: ultramarine


Val

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Reply #11 on: November 20, 2010, 05:05:30 PM
 :clap: Thanks everyone, I'll get a start on that tomorrow. I think once I make a chart and can see the variances it will become a lot clearer.  :)
Cheers, Val

”Creativity is allowing yourselves to make mistakes. Work on knowing which ones to keep!”

- Alvaro Castagnet


 

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