Wednesday, November 25, 2015

Paint Basics

Knowing Paint Better

Watercolour Paint - Daniel Smith, QoR

I have wondered for a long time about the true nature of artists paints.  I have been searching for answers to some questions about how paint functions and how watercolour, oil and acrylic paint compare.  Here is what I found out.

What makes paint dry?  What are artists paints like on a microscopic level? 


Watercolour paint is a solution of gum arabic (the binder) and water and microscopic-sized pigment particles.  Gum arabic is an exudate from a gum tree.  More precisely it is the sap of two species of acacia trees.  Microscopically it is a long chain that is soluble in water.  The pigment particles are in suspension in the liquid.

When watercolour paint dries the water evaporates leaving the gum arabic to become a solid which holds the pigment particles in place. You can lift dried watercolour paint because the gum arabic will redissolve in water. 

Watercolour Paint in Palette

Acrylic Paint 

Acrylic paint is a suspension of spherical polymer particles (about 1 micrometer in size) in water.  The pigment particles are also suspended in the water.  When acrylic paint dries the water evaporates, the polymer particles coalesce to form solid sheets which trap the pigment particles.  You cannot lift this paint because the polymer is now a water-insoluble solid.

Gesso is made up of water, acrylic polymer and gypsum (calcium sulfate) particles. 

Oil Paint

Oil paint is a mixture of an organic solvent like turpentine or mineral spirits and drying oil (linseed oil, tung oil) and pigment particles.  The oil is soluble in the solvent so they do not separate.  The pigment particles are so small they remain in suspension.  When oil paint dries the solvent evaporates leaving the oil and pigment on the surface.  When on the surface the oil oxidizes and becomes a solid which is no longer soluble in either solvent or water.  
Why can you put oil paint on top of acrylic paint but not the reverse?  Oil paint can be put on top of acrylic paint (or gesso) because the dried acrylic paint is essentially a plastic sheet and the oil  will bond to it.  However, you cannot put acrylic paint on top of oil paint because the dried oil paint is hydrophobic and it repels the water in the acrylic paint thus causing it to flake off.  

How do each of these paints stick to a paper/canvas substrate?  They use a process called wetting in which they form a strong physical bond with the surface.  

Why do we need gesso on a canvas before painting it?  It helps to keep the paint from absorbing into the substrate and it also smooths out the surface. 

What does water do when added to watercolour paint (oil to oil paint or water to acrylic paint)? It reduces the viscosity, which means it dilutes the paint.  If too much is added to acrylic paint, it will not harden.  When considerable dilution is desired you should use acrylic medium which contains acrylic polymer particles and so it acts the same as the paint. 

Paints usually have a fourth component termed an ‘additive’ which is used to make the paint flow well, maintain its quality in the tube, keep it homogeneous, etc.

Water Miscible Oils

Water Miscible Oil Paint is a modern invention that may be going to revolutionize the oil painting industry.  Time will tell how well it is accepted.  Right now it is just in the trial stage by most artists.  How is it different?  It can be thinned by just adding water and brushes can be cleaned in water only.  No solvent is needed.  How is it formulated so this can happen?  

The oils in oil paint are made of long-chain fatty acids.  Most of these fatty acids are hydrophobic (water repelling) so the paint is incompatible with water.  However, in normal oil paint there are normally some hydrophilic fatty acids (water loving).  If this portion of hydrophilic fatty acids is increased, the paint becomes water soluble.  Water can then become the 'solvent' for the oil paint!  Just like magic, the paint can then be thinned with water and clean-up done with water.  Organic solvents (turpentine, mineral spirits) are no longer needed.  

How does water miscible paint dry?  The water evaporates leaving the oil and pigment on the substrate.  The oil then oxidizes and hardens, trapping the pigment. 

Pigment particles 

Pigment particles are made from natural and artificial compounds which are pulverized into ultra-small particles (0.1 to 100 microns).  Some pigments are derived from naturally occurring compounds like iron oxides (ochre, umber, sienna), carbon black, lapis lazuli.  Others are from manmade pigments which are usually based on metal compounds like cadmium, chromium, cobalt, copper, lead, titanium and zinc.  When a tube of paint is labelled ‘hue’ it means that the colour will be almost identical to the genuine paint for which it is named.  However, the pigment is not the same as in the original. It is often a cheaper or a blended form. 

Golden has recently marketed an innovative watercolour paint called QoR, an acronym for ‘Quality of Results’.  They are advertising it as possessing some nice features like:  incredibly smooth transitions, good flowing while maintaining liveliness on the paper, excellent resolubility in water, excellent glazing qualities, vivid depth of colour in one stroke, greater resistance to cracking and flaking, more density of colour than traditional watercolours, and easy clean-up.  Besides these stated advantages they have marketed new  grounds and mediums to go with the paint.  These apparently increase gloss, improve flow or wetting properties, and allow you to achieve different textured surfaces.  It is exciting to be part of modern advances in paints and materials.

QoR paint has a newly formulated binder called Aquazol.  It appears that the company is keeping a tight lip on its formulation.  I have not been able to determine its chemistry but expect it is an acrylic or an acrylic/gum arabic mixture.  I have used QoR paints only minimally so far and find them bright and easy to use.  The only negative is that I have found the Aquazol has separated somewhat from the pigment in one or two of my tubes.  Time will tell how successful they are.  They are probably the forerunner in a lot of new products in the watercolour industry.

There is some discussion about QoR paints not ‘lifting’ as well as traditional watercolours.  I have done a short, uncontrolled test on my own and find that to be true.  See the photo below which shows lifting in traditional paint compared to QoR paint. The two on the left show lifting from traditional paint and the one on the right shows lifting from QoR paint.   I used the same amount of water, the same bristle brush and the same number of strokes on each followed by dabbing with dry paper towel.  It appears the traditional paints lift better than the QoR paints.  However, this is too simple a test to draw any conclusions.  One would need to do many more samples and under more controlled conditions.  I like the QoR paints and will continue to use them and time will tell how they work out.  

Lifting Watercolour Paint; Traditional Paint Left and Centre, QoR Right

Thursday, November 19, 2015

Vagrant and Out-of-Season Birds

Unexpected Birds

Every fall we are privileged to have vagrant birds arrive here.  A vagrant is a bird that is beyond its normal range.  In other words, its presence here is accidental.  The Franklin's Gull shown below is one such species.  It appeared in a ploughed field in Ste-Marie-de-Kent last week and has remained for several days, associating with a large group of Ring-billed Gulls.

Franklin's Gull [Brian Stone Photo]
 The Franklin's Gull inhabits mainly the mid-continent of North America where it breeds.  It winters in fresh water marshes off the Pacific coast of South America.  It lives inland in North America because it likes ploughed fields and prairie land.  This trait earned it its common name,  'prairie dove'.

It is a medium-sized gull being 36-38 cm long (14"-15").  It is a black-hooded gull and has prominent white eye crescents and a slaty-gray back.  In winter the black hood is washed out with white and the bill changes from its prominent orange of the breeding plumage to black with an orange tip.

Franklin's Gull [L Nichols Photo]
The bird which arrived here is a 1st winter bird.  Note the dark gray-brown on its back.  Older gulls would be all gray on the back.

Ring-billed Gull and Franklin's Gull
Shown above is a Franklin's Gull with a Ring-billed Gull showing the difference in size.  This Franklin's Gull was seen at Scotch Lake several years ago in the fall.  Note it, too, is a 1st winter bird.

Overbird [Nelson Poirier Photo]
The bird shown above is an Ovenbird which has been coming to a feeder in Moncton.  This species is a common warbler species seen here in summer.  It is unusual because it is still here, appearing healthy and coming to a feeder.  It normally feeds on the ground usually in the forest.  It is not a feeder bird at all.  It is called an 'oven' bird because of the domed-shaped nest it builds on the ground with a side entrance.

The season for rare fall vagrants and out-of-season birds is still upon us.  Keep a close eye for anything unusual.

Thursday, November 12, 2015

Art: Watercolour

Watercolour Workshops

The Storm
Recently I have had the good fortune to attend two watercolour workshops.  The most recent was presented by Peggy Holt of Fredericton.  Peggy put on a day filled with excellent instruction and demonstrations showing her work and skill.  She motivated us with her excellent teaching skills.  The session was complete with coverage of nearly every possible aspect of watercolour painting.  She even introduced some cutting edge ideas!  

The painting above was done from a photo which she used to have us paint a landscape.  I was intrigued by the severity of the storm and what it was doing to the landscape.  I enjoyed putting that on paper.

At the end of September I attended a 5-day watercolour workshop put on by the Canadian Society of Painters in Watercolour in Cornwallis, NS (see previous post).  This was a fantastic experience.  There were 8 teachers covering all aspects of watercolour painting.  Each was a master of her/his area.  We could choose to spend a day or more with our choice of 5 of them.  Some selected more than one day with some but I chose a day with 5 individuals.

Calgary Cityscape
One instructor was Rex Beanland from Calgary who specializes in cityscapes.  We had a fun day learning his techniques.  The painting above is what I was able to execute.  Getting the perspective right was the challenge.  

The symposium was also filled with extras.  We had a lobster banquet one evening.  On another we had a 2-hour presentation on Golden products.  We were shown dozens of their products with concrete examples of what they can do.  We finished the evening with lots of take-home samples.  Other extras included a life drawing session, night painting demonstration, and a welcoming reception.

I am not sure I am a watercolorist but I certainly enjoyed being shown what they can do.  Most of them are transparent and I love the luminosity they show.  It is also interesting to see what they can do by themselves as they move around on the paper.  They are a challenge to use but a rewarding challenge!

Thursday, November 5, 2015

Late Birds

Saying Goodbye to Our Summer Friends

Eastern Phoebe
One thing birders often do is keep track of the dates during which species of birds are actually here in New Brunswick.  This gives us early and late dates for each species and also information about what the species is doing, its arrival and departure, its geographical locations, its movements from place to place for food, nesting, etc.  

Two species I watch carefully are the Eastern Phoebe and the Ruby-throated Hummingbird.  They feed and nest around our place and are easy to monitor.  I consider them my friends and am always sorry when they leave.  I wish them well as they wing to warmer climes each fall.  

Eastern Phoebe
The Eastern Phoebe arrives earlier than many of our migrants.  That is because it is a bit hardier than some flycatchers, of which it is one.  Its main diet is insects which it catches by flying from a good vantage point like the one on the roof above.  It also eats berries and other fruit so it can survive a bit better in cold weather when insects are difficult to find.  The last phoebe we saw here in Fredericton this year was on October 11.  We saw one later than that, on October 18 on Covedell Road near Tabusintac.

It can be a problem for flycatchers if they return too early in the spring.  If the weather is unusually warm, sometimes they will appear early.  That is fine if some insects have hatched providing food.  If, however, the weather turns bad and there are no insects about, it can be difficult for our phoebes.

Ruby-throated Hummingbird Female
Another species I watch carefully for early and late dates is the Ruby-throated Hummingbird.  They arrive almost every year on Mother's Day weekend.  Sometimes it is a day or two on either side, but I can usually depend on having visitors to our hummingbird feeders on Mother's Day weekend.  They usually leave around Labour Day weekend.  This year we saw our last hummingbird on September 23.  I still have my feeders out in case an unusual hummingbird shows up looking for food.  That is very unlikely but it has happened in NB before in late fall and in almost every case the hummingbird has been a rare species.  One time it was a Rufous Hummingbird and one time it was a Broad-billed Hummingbird.  You just never know what surprises our avian visitors have for us.

Ruby-throated Hummingbird Male
Ruby-throated Hummingbird Male