Sunday, 28 September 2014

Oil Pigments Color Temperature, Paint Transparency and Hue Saturation

The artists’ first encounter with oil painting will be presented with a vast array of oil pigments in art shops. Many blues, browns and reds could cause confusion on which oil pigment to choose for painting. The cost of art materials will also influence the number of oil tubes to purchase. Which are the best oil colors to buy and how does each oil color differ regarding color temperature, coverage and intensity?

Different Blues in Oil Colors

Types of Pigments in Oil
A walk into the art shop will educate the artist on the number of art pigments available in the art shop. For instance, in regards to blue, the following can be found: French ultramarine, cerulean, Prussian blue, Monestrial blue, Pthalo blue, cobalt blue and more. The same applies to reds, greens, yellows and browns. I avoid packaged sets of oil colors, which do not work out cheap in the long run, as unnecessary hues are often included (and often the omission of an essential color). I will purchase the tubes separately, creating an essential collection of oil colors that will be used.

Pigment Temperature
Which Oil Pigments to Use

Most artists will use just a dozen or so oil paints (as do I) which includes a warm and cool version of the primary colors (red, yellow and blue) as well as earth colors, a few extras and white. I find the following oil pigments will mix just about any color needed for painting: Titanium white, French ultramarine, Pthalo blue, permanent rose, cadmium red, lemon yellow, cadmium yellow (pale), burnt sienna and burnt umber. The following are also useful extras: cerulean blue, viridian and alizarin crimson (an old favorite).

Using Oil Paints for the First Time

A good way of learning about the nature of each pigment is to apply each alone on a primed piece of card. The video clip informs on how each oil color differs in translucency and color temperature (how warm or cool it appears). Nothing quite equals trying out each color for yourself as opposed to reading about them, but basically, each color will have its own intensity, opacity, temperature and translucency. Find a YouTube clip on how I applied each oil pigment neat onto white card.

Translucent Blues and Reds

Color Temperature of Blue and Red
French ultramarine is quite a translucent color, not having the opacity of cerulean or cobalt. Pthalo blue is also quite translucent. Both require a little titanium to add coverage, but the addition of white will change the nature of the blue a little, killing its sparkle. The close up image shows translucent and opaque blues and reds. See how the translucent paint allows a little of the white gesso to show through, leaving a patchy feel to the paint layer.

This can be seen with viridian, which is also a transparent color. I applied it neat, and then with a little titanium white.

Opaque Pigments in Oil Colors

Color Temperature of Yellow Brown
Again, we can see here that lemon yellow and burnt sienna are rather translucent, where as cadmium yellow and burnt umber has more coverage. Translucent colors when applied over a white surface will appear vibrant. Opaque colors has good coverage but lacks this vibrancy.

Colour Temperature of Pigments

How warm or cool does the color appear? This is known as colour temperature. A warm color will be bias towards red, a cool colour will be bias towards blue. French ultramarine has a violet cast, meaning it has a warm colour temperature. Cerulean blue and Pthalo blue appears cooler. Cerulean has a slightly greenish tinge. Again, cadmium red has an orange-glow, giving it a warm cast. Permanent rose and alizarin crimson are cooler reds, having a violet cast. Similarly, burnt sienna is a warm, toasty brown; burnt umber is cooler. 

Guide to Oil Pigments Transparency and Colour Temperature

Adding White
To summarize, find a guide to the nature of each oil pigment below:

French Ultramarine: a warm, violet blue, tends to be translucent
Pthalo blue: a cool, deep blue, tends to be translucent
Cerulean blue: a cool, greenish blue, tends to be opaque
Viridian green: A sharp green, tends to be translucent
Permanent rose: a cool, violet red, tends to be translucent
Cadmium red: (deep to pale can be found) but tends to be orange-red, rather opaque
Alizarin crimson: a deep, violet brownish red, tends to be translucent
Lemon yellow: a pale, acidic yellow tends to be translucent
Cadmium yellow: (deep to pale can be found) but tends to be warm, orangey, rather opaque
Burnt sienna: a warm toasty brown, tends to be translucent
Burnt umber: a cool, coffee brown, tends to be opaque
Titanium white: a brilliant, opaque white. Will add opacity to any pigment it is mixed with.

More Articles about Art Pigments

My Science of Color site
Recommended Oil pigments for painting
How to make oil painting cheaper

Saturday, 27 September 2014

My Town Painting Looks a Mess: Help for Painting Houses and Harbors

Painting a town scene featuring lots of buildings and architectural features may cause frustration if the detail looks splodgy and lines wonky. How can the artist paint a town or harbour without the detail looking messy and amateurish?

Mistakes in Painting Towns in Detail

Painting a Torquay Scene
An artist presented with an intricate landscape scene for painting may be disappointed with the final result. The following oil painting practices may have contributed to an unsatisfactory town painting:

Completing the painting in one go, causing the artist to rush the end through tiredness. The result may be brush marks that appear carelessly rendered in the form of smudgy lines or paint that bleeds into neighbouring colours.

Not planning the underdrawing, causing mistakes to be inherited in the upper paint layer. No amount of artist precision will make up for an inaccurate drawing.

Poor art materials, particularly cheap brushes with no shape or springiness. This will rob the artist of paint control, causing the pigment to go into unwanted areas.

Applying the oil paint straight onto the white surface. Unless the artist is supremely confident, a degree of guesswork will result in a scene that is not centred upon the art surface properly or an imbalance in tones.

Another problem is that often, complex landscape scenes will feature darks and pales against one another. The result could be unwanted colour contamination within a small space. A messy painting may result.

How to Prepare for a Town Painting in Oil

This demonstration features Torquay Harbour on the Devon Coast in the UK. To make the painting easier I had prepared two acrylic underglazes prior to the oil painting: one to kill the white gesso, the other to reinforce detail so that the drawing will show beneath the glaze prior to oil painting. Prior to these, an accurate drawing is essential.

My art instruction YouTube clip shows how I prepared the underglaze for painting Torquay in Devon. Scroll to the bottom to see the second clip: the actual oil painting.

Tips for Intricate Town Painting in Oil

When faced with painting an intricate coastal town, the following are essential: a, clear photograph, fine quality sables for detail: no’s 1, 3 or 6 will suffice. A smooth art surface (fine canvas is OK, but the grain can make drawing smooth lines tricky). I used primed MDF. Don’t use old oil paints that have thickened with time.

Art Tutorial on Painting a Detailed Coastal Scene

The Under Drawing of Torquay
Torquay Harbour posed challenges in that it presents lots of tight detail in the form of houses, windows, roofs and boat masts. Rather than complete the painting in one go, I did so in stages and on separate days. Each painting session lasted only an hour or so with breaks.

Firstly, I conducted the underdrawing. Time is needed to get this right, but don’t go overboard with detail, as this will be covered with the oil paint anyway. I simply ensured the houses were drawn with reasonable accuracy and the composition centred upon the art surface in the way desired. A sharp HB pencil and eraser was used.

Underpainting with Acrylic Paint

Underdrawing and Glazing a Painting of Torquay
So that the drawing will show through the glaze (to be applied next), I reinforced the drawing by overlaying the lines with dark brown acrylic paint from a fine sable. Illustrating dark areas serves another purpose in that it supports the oil paint layer. Don’t use dark lines on areas that feature no lines or pale areas, such as the foreground reflections and the clouds, as the dark acrylic will show through the oil paint.

Art Lesson on How to Paint Torquay Harbor

Leave Lose Brushwork Till Last
Once the brown acrylic paint was dry, I overlaid the drawing with three coats of diluted blue acrylic paint. The application of one wash often results in unwanted streaks and brush marks. Three coats will create a more uniform appearance to the underglaze. This means that the overlying oil paint (which comprised mostly of pales around the houses) will be easier to key in to the surrounding.

Harbour Painting in Oils

Once the acrylic underglaze had dried, I began the oil painting, which was on a separate day. As can be seen, this preparatory technique means the artist is not faced with the prospect of laying colour straight onto a white surface or of guessing where to lay the paint. Fine sables are essential for detail such as windows and guttering. I used rounds no’s 3 and 6. Wider sables were used for the foreground reflections and the clouds.

Painting Detail Tips Art Instruction

Always begin with the most exacting area whilst feeling up to it. In this case, I began with painting the pale house frontages with varying amounts of white, burnt sienna and cadmium yellow. Painting pale prior to dark means the dark cannot contaminate the pales. As can be seen here, the houses vary slightly in their cream tones. It doesn’t matter if the pale colour goes over the windows, as the dark brown acrylic paint shows through. Reinforcement in the form of dark oil paint can be applied later.

This second YouTube clip shows the oil painting stage. Again, I began with the trickiest areas. I left the looser brushwork until last. This consisted of the sky and reflections.

Tips for Painting Towns and Cities

As can be seen, the huge challenge of painting towns with lots of buildings can be broken down into manageable tasks on separate days. In this case, the stages consisted of: the drawing (take time to get this right), overlaying the lines with acrylic paint, overlaying the composition with a series of acrylic glazes. Finally, the oil paint can be applied on a separate day via fine sables. Often, a touching up session is required once the oil paint is dry. This might be to sharpen detail around windows or straighten lines. A little linseed oil will help the paint flow.

More Tips for Oil Painting

Build confidence in oil painting
Torquay Harbour worked from a photo taken by Joseph Busby