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Guide notes on drawing and painting in watercolour

Introduction:

The following notes are based on material offered to TAG members during early sessions in the group's existence, and they are reproduced here as a guide for new members (or as an aide memoire for members with some experience).

They comprise notes on materials and drawing techniques, followed by some suggestions about composing watercolour paintings.

For more comprehensive guidance there are two good "basic" books you might consider purchasing:

  • "Watercolour for the Serious Beginner" by Mary Whyte  (1997) published by Watson -Guptill Publications, New York.
  • Watercolour Workshop" by Glinis Barnes-Mellish  (2005) published by Dorling Kindersley

(Both should be available through 'Amazon' on the internet, or from most good booksellers.)

Materials

Paper:  Three types:  smooth (hot-pressed); medium (NOT = "not rough" dry-pressed); and rough (dry-pressed).  Several weights from thin (72 lb), 90lb, 140lb (the best general use paper); and 200 or 300 lb.  Bockingford is the cheapest, and other good makes are Whatman, Fabriano, Saunders Waterford, and so on.

Papers are produced in Imperial size sheets (22" by 30"), and the most economical way to buy them is by the sheet.  Cut into four quarters they provide, potentially, eight painting project opportunities, since most papers can be used on both sides.  Half Imperial 140 lb or less sheets should be "stretched" (dampened and fastened down on all four sides to a backing board using gummed paper tape, and allowed to dry);  this prevents the paper from buckling when washes are applied.  Watercolour boards can be purchased which do not need special attention in this way, and 'blocks' which are gummed all round also do not need stretching.

Cartridge paper is intended for drawing, but can be painted on, especially when making preliminary sketches, but it does not suit 'finished' watercolour works.

Brushes:  There are round and flat brushes as basic tools:  round brushes come to a point and are good for lines and fine work, while flat brushes (like those you would use to paint your house, but much smaller) are good for painting broad washes.  Sable hair is the most expensive, but artificial (nylon) brushes are very practical for practising.  A good selection would be a No. 9 and No. 14 round, and a half inch and a one inch flat brush, plus a "rigger" a small round brush with long hairs which is useful for twigs and thin lines.

Pencils:  The best 'general purpose' pencil is probably a 2B pencil, which is soft enough not to make indentations in watercolour paper, and versatile enough to make rough sketches in a sketchbook or on sheets of cartridge paper.

Paints:   The choice boils down to using tubes or pans, with either "artists" or "student" quality.   Tube paints are soft and easy to mix, and artists quality paints have less filler in them, so give better results, but student paints ("Cotman paints are fine to learn techniques with and are cheaper, so if you don't want to spend too much at first, they can be an acceptable choice.  The question of choosing colours is examined in more detail under the section on "the colour palette", below.

Miscellaneous items:  Some of the extras which come in useful include the obvious ones:  a white pallet for tube paints (plastic pallets are available in art shops, although a good substitute is a plastic tray - butchers' trays used to be easy to find until "elf and safety" rules made them undesirable, but a reasonable alternative is a small white plastic plant pot tray); an eraser (preferably a "putty rubber" which is soft enough not to damage the surface of watercolour paper when you need to erase some of your initial drawing lines), and a pencil sharpener (some folk like to use the small metal sharpener with a built-in blade, but for getting a good point on your pencil you can't beat a small knife -  either a pen knife, or better still, one of the small retractable blades in a plastic holder, which are easy to use and safe when closed up).  Other items are a small bottle of masking fluid for reserving areas before you paint which you want to keep as highlights, and perhaps a bottle of gum arabic, which helps to strengthen the tone of watercolour paint when mixed with it on your pallet (a small dollop in the corner of your pallet is sufficient to dip the tip of a brush into after taking up the paint).  Finally,  a roll of kitchen paper for cleaning your brushes and pallet, and don't forget a small plastic bottle for water - plus a container to pour the water into - for when you venture outside for a plein air session.  (These last two are easy to forget when you are packing your things for a session in the country!)

Drawing

Note that in any drawing, it is useful adopt a set procedure each time.  First of all think about how you hold your drawing instrument (whether it is a pencil or a paint brush).

Using the finger gripUsing the "finger grip"

The "finger grip" illustrated above differs from the "writing grip" (below) in that it obliges you to hold your hand away from the paper -- unlike the writing grip in which you rest the heel of your hand on the paper. The latter is fine if you need to draw fine lines and detail, but it is difficult if a free and easy drawing action is needed, as when you are drafting out general shapes, or if you draw guidelines (as when you divide the paper into thirds, both vertically and horizontally, in order to start composing a painting or drawing, as explained below). This is when you should normally use the finger grip, since it allows you to move your hand and your whole arm freely, producing lightweight lines which can readily be erased if you wish to get rid of them. The writing grip, on the other hand, is for when you wish to draw or paint detail, when you need more control.

Using the finger gripThe "writing grip"

Composition and Perspective

Having sorted out your pencil-holding technique, try following the system outlined below, to make sure the images or subjects you want to portray are not too large or too small in your picture area, and are in their correct perspective.  Many people find "perspective" a daunting problem, but all it is, is a technique for making sure that, as in real life, distant objects are the correct apparent size, smaller than those which are close to you.  See the note at the end of this section for getting perspective right.

Before touching on perspective, some thought needs to be given to composing your picture, and the following procedure offers one method of composing which produces results which are satisfying to the eye, using the "one-third rule".  [There are many ways of composing pictures, others being triangular, circular  or "Z-shaped" compositions, and none of them is "right", as there are no rules which have to be followed, other than those which help you get perspective right.  So if you want to forget about the "one third rule" for composing your picture, that is up to you.  But if you think about it, there is some logic in avoiding the centre of the picture for your main subject.   A painting which portrays a scene in which the main subject is "off centre" or asymmetrical usually is more satisfying, especially if it has a supporting feature to balance it.  This is the real 'justification' for the one-third rule.]

The "one-third rule"

All this means is that you start your composition by dividing your painting area into thirds, whether or not it is in "landscape" (horizontal) or "portrait" (vertical) format.   In the diagram below, just two of these one-third lines are shown, with the 'main subject square' centred on where they cross - a good place for a focal point.   Notice that the main subject square is itself about one third the width and height of the painting area, a good size for a building if that is your principal subject: any larger and it dominates the picture too much, and smaller it becomes rather insignificant.  This 'rule of thumb' is worth following whatever your main subject (a group of trees, a vase of flowers, or a figure).   The balancing second subject is much smaller (about half the main subject).

Perspective

1.   Draw in the eye level line (an essential guide for any landscape picture) from left to right, either one third up from the bottom, or down from the top, of the drawing area, depending on whether you want plenty of sky area, or plenty of foreground.   When drawing from life, this is the 'horizon' when you look straight ahead;  in a photograph, the eye level can be found by looking for clues in the picture - where horizontal features on buildings are level with the bottom of the photograph.  Remember that the eye level line is not usually the ground line of a foreground feature like a house:  the eye level will be close to the top of a doorway (imagine yourself walking through it).

2.   Draw two vertical lines, top to bottom, each one third from the sides of the drawing area.  These vertical lines, in a 'normal' horizontal format picture, usually divide the area into a square and a vertical oblong.

3.    Draw a large square, one-third the width and one-third the height, of the drawing area, centred on where the vertical line you plan to use for the location of your 'main subject' and the eye level line cross.   This square defines the approximate size of the main subject of your drawing, and as previously mentioned, is a good place to put a focal point, or centre of interest.

4.   Draw a small square half the size of your 'main subject square' (ie. one-sixth the width/height of the drawing area) centred just to the far side of the second vertical line (ie, away from the centre of the picture).   This square defines roughly where you will place the supporting or 'second subject' of your drawing.

5.  Draw two lines starting from the bottom and one side of the picture, meeting at the point where the vertical and eye level lines cross within the large square.  These lines (labelled the "leading triangle" in the diagram above)  form an 'arrow head' which leads the viewer's eye towards the centre of the main subject square, which is where you will normally place your focal point.  Use these lines to construct a path or river leading into the picture:  try not to run one edge straight into the bottom corner of your picture - it works better if you have it cutting the side of the picture frame.

Please note (if you are a 'beginner'):  

All these lines are 'guide lines' which you will probably need to erase once you have completed your drawing, hence the need for them to be drawn lightly, using the finger grip throughout.  Eventually, you will be able to visualize these guide lines instinctively, and will not need to actually draw them on your paper.

Remember that the diagram shown above places the "main subject" in the bottom right segment of the composition, but the layout can be reversed so that the most important feature is on the bottom left, or even top right or top left.

The see-saw priciple

Another feature of the "one-third rule" is that it produces a composition which is asymmetrical, automatically giving a balanced feeling to a painting, which relies upon the "see-saw" principle, where by a large object is closer to the centre and is supported by a smaller feature closer to the opposite boundary of the composition.  (Think of a fat boy sitting on a see-saw with a thin boy.)

This helps to make a picture interesting and not boring.  It also helps with the painting process, as a large object can be difficult to render if it has large areas of blank space (for example, a building without windows in an otherwise blank wall,  although you could put a tree or a person in front of the wall, or some strong shadows across it). 

GETTING  PERSPECTIVE RIGHT

The important thing to remember when perspective becomes a problem is that it is all based on using a device to ensure that the  size of features is correctly rendered, to create the impression that distant objects are further away from the viewer than nearby objects.  Any photograph of a scene shows you that distant buildings are much smaller than one which is a few yards away. There are a couple of points which are all important.

"RULE ONE"   EYE LEVEL is crucial!  As well as breaking the ice when you are faced with a blank sheet of paper, and wonder where to begin, drawing in the eye level line is necessary to give you a basis from which to proceed with getting your perspective right.  So do get into the habit of always drawing  that line first.  (Once you have grasped the way it works, you will find your can visualise the eye level line instinctively when you draw buildings or such features as fence posts leading off into the distance.)

"RULE TWO"  YOUR "CONE OF VISION":  This is important because whenever you draw a scene, you are doing so from a fixed point of view.  Just as when you take a photograph of a scene, the camera records what is in front of it from a fixed position, so, when you draw or paint a scene, you will end up with a work which records for the viewer, what you saw when you composed that picture.  The "cone of vision" is a term which describes what you can see clearly in front of you when you look straight ahead, without moving your head, and this is basically a 'field of vision' which is about sixty degrees wide.  It is what you can see if you extend your arms straight in front of you, keeping them the width of your shoulders apart.  Any objects outside that field of vision you are aware of, as they fall within your peripheral vision, but to see them clearly you need to look directly at them, moving your head to do so.  As soon as you move your head, your "cone of vision" changes, and so does the perspective of any objects which were only in your peripheral vision beforehand.  So, once you have grasped that, you should have few problems with getting your drawing of a scene in its true perspective. 

Cone of Perspective

The role of "vanishing points"

"Vanishing points" are imaginary points on your eye level, and can be found by extending lines which you draw, for example,  to represent the top and bottom of sides of buildings which are at an angle to you when you look at them from your fixed viewpoint, within your "cone of vision".  It stands to reason that the distant corner of a building is going to appear smaller than the nearest corner, so to help you get your drawing of the building right, you should extend the lines to infinity (which is another term, in this context, for a vanishing point on the eye level line, or horizon, if you could see that far without distant obstructions.)  In the following sketch of a house, seen from an angle, you will see that these lines actually extend to two vanishing points ("VP"s), one on the right and one on the left of the building as we see it.  This is because we can see two sides of the building.  (For the moment, ignore the reflection shown below the house -- this is discussed later).

House in Perspective

"RULE THREE"  THE NEAREST CORNER   Yet another rule - but this is the last one!  When you start to draw your house, barn, or whatever, having decided that a 'three-quarter view' of it is best (more interesting than a 'flat' all square view) always draw the nearest corner as a single vertical line, first.  Its up to you how long (high) that line is, but it will represent the height of the house as you wish it to be in your finished drawing.  Only you can judge how large you want the building to be in your composition, but as suggested above, a good 'rule of thumb' is to keep it to no more than one third the size of the overall drawing you are making. Don't forget to extend the bottom of the line below the eye level line. Assuming you intend the picture to appear as though you are standing on level ground in front of it, you eye level line is about five feet above ground level. 

Now you should have two lines on your paper, your eye level, and the nearest corner of the building.  Have a good look at the subject you are representing, whether it is a "live" on-the-spot scene, or a photograph, and assess angle, or slope, of the top of the building's front wall as it appears to recede from your viewpoint (to the left of the building in the sketch).  Start at the top of your 'nearest corner' line, and draw that "slope" line until it meets the eye level line, which is the first vanishing point.  Now connect the bottom of the vertical line to the same vanishing point.  This will be a very 'shallow' slope, as , as the far corner of the building is not that much below the eye level. You can now assess where to put the far left-hand corner of the front of the house, and can draw that vertical.  The lines extending to the vanishing point can now be erased as they are redundant.  The same procedure can be followed for the side wall of the house, on the right, which is visible to you.  You will now end up with a box shape which should look like the house below its roof.        

Dealing now with the roof, once again you have to judge the slope of the roof, and draw that in from "A" up to the peak of the roof where the chimney is, this point being found by drawing lines which  join the opposite corners of the side wall of the house (as shown on the left of the sketch), and draw a vertical line through the point where those cross lines meet.  This establishes the true centre of the side wall in perspective, and thus gives you where the peak of the roof lies.  You then connect the peak to the first "VP" on the right.  This now gives you the correct perspective for the roof.

Note that a chimney, since it has four sides which are parallel to the house walls, has exactly the same vanishing points as the house.  You will see also that window ledges and the tops of any doors, rely on the lines to vanishing points in the same way.  [Use the same rules for drawing fence posts retreating into the distance.]

Reflections

If a building sits (as in the sketch) behind a pool (or a puddle of water) it is reflected in that water and follows exactly the same perspective lines as those governing the actual building.  It is necessary to be a little careful about extending the nearest vertical corner line into the water, since the reflected position of "A" is determined by the distance from the bottom of the house wall (at "X") to point "B".  You will note that the amount of roof seen in the reflection is not the same as in the drawing of it above water, because the reflection gives an oblique view of the roof: by the same token, more of the underside of the eaves, where the wall joins the roof, is seen in the reflection. The corollary of this is that the further away from the reflecting pool the house lies, the less of it will be seen in the reflection.  Remember this when you paint reflections of distant hills in lakes or rivers. Something next to the water line (the small post to the right of the house) has virtually an exact mirror image when it is reflected.

If you follow these guidelines for yourself, perhaps reversing the building, so that your drawing of the house has its front facing to the left, instead of to the right, you should begin to grasp what may appear to be very complicated instructions, and you should have no problems with perspective in future.

Sketching "shapes" (and not objects)

Good practice for drawing landscape features is to follow a controlled sequence of pencil marks.    The important thing to remember is that you can develop one method for drawing anything, whether it is a face, a flower or a building, and that method is to look at the object not as an object (a face, a flower or a building), but as a series of shapes which have to be recreated on paper.

If you write the capital letter "A", you basically draw two sides of a triangle, and place a crossbar between them.   If you see a face, draw an oval, and divide it by a horizontal line, placing the eyes on that half-way line.  And so on.  A flower is probably a circle or an oval, depending on its angle to your point of view, and it is then divided into segments to represent its petals. Forget what the objects are, just treat them as shapes.  Try turning the photograph upside-down, and copy its shapes onto your paper - this helps you concentrate on the shapes!

Shapes

Try analysing any photograph of "objects" or a scene you would like to practice drawing.   As an example, the photograph above may look complex, but it boils down to a series of quite simple shapes:  a vertical block (note it is conveniently on a "one-third" line) for the totem pole; a triangle for the background hill; and a series of rectangles for the buildings and vehicles.  Other shapes are a small triangle for the anchor and its support, and a circle for the tree.  The first line you draw should be the eye level, one third up from the bottom and running in this picture along the base of the large building on the left.  The eye level gives you the essential information you need to get the perspective right, as described below. (You could sit a brightly-clothed figure at the base of the totem pole as a focal point.)

Note that all these shapes are best seen by half closing your eyes, and squinting at the picture.  If you were in the open air, you squint at the three- dimensional shapes in the scene, and analyse them in the same way. Squinting in this way helps you to identify the main darks and lights (tones) so you can create an interesting pattern.

It is good practice to drawn a small 'thumb nail sketch' of the scene to allow you to get a feel for it, and to work out how you plan to make some parts darker than others.  To avoid a scrappy appearance in your sketch (and eventually your painting) try to connect the darks together with shadows or some other device, such as grouping the dark parts of objects into one overall shape.

Now sketch in lightly the overall shapes of the objects you have identified NB. having first marked in your eye-level line!, taking care to judge their correct positions and sizes.  One way of doing this is to choose one object (say, the large building on the left, which is about as high as it is wide) and use it as your "standard measurement" for deciding on the size of the other objects:  the anchor is about the same height as the building, and the totem pole twice its height.

Only when you have got a series of fine outlines showing accurately where the objects you want to include in your drawing/painting are to be, should you start to draw the individual objects more carefully.

The final stage in drawing these views is to shade in the medium and darkest tones, so that you have a good feel for the scene.  Cross-hatching is probably the best way to carry out this shading.  A lot can be learnt from drawing a scene in the foregoing way, before starting to paint it, so plenty of practice in drawing is good!

This procedure will work for whatever subject you want to draw!

The colour palette

Having decided which paint manufacturer you plan to support, and whether you will opt for tubes of paint or pans in a paint box, start by limiting your palette (that is the range of colours you plan to use) to as few as possible.  This is because you will give yourself the best chance of avoiding the biggest bugbear of watercolour painting - namely, producing "mud" when you mix colours - if you keep to a small selection.

What you need to know is that, because of some chemical reasons, paint manufacturers have found it virtually impossible to produce any 'pure' colours.

The effect of that is that each of the three primary colours, red, yellow and blue, (from which all other colours - 'secondaries' such as green, violet and orange, greys, browns and so on - can be produced) have elements of the other primaries in their make-up, or spectrum.  So every red has a bit of blue, and a bit of yellow in it, and so on.   For this reason, to have a chance of mixing a really good range of colours, you need a "warm primary" and a "cool primary" in each case.  (Warm means tending to be hot or reddish, and cool means it tends to be cold or blue.)    Some colours which fall into the different categories are:

                                           warm                            cool
        RED:                    Cadmium Red                Permanent Rose
        YELLOW:            Cadmium Yellow*                  Lemon
        BLUE:                French Ultramarine*          Cerulean Blue                                 

*  There is a proviso here:  a fairly medium yellow, tending to warm, is Aureolin, and a medium blue is Winsor Blue (Red Shade).  If you want to limit your palette to just one of each of the three primaries you could do worse than have just these two separate colours, and add Permanent Rose to them. And to complicate matters further, it helps to have a dark and a light brown in your palette too, and you could have Burnt Umber and Burnt Sienna as extra colours.

If you are feeling particularly extravagant, you could have all eleven colours, which is not too bad when you consider that paint box producers have a whole range of colours, greens, black, and white in them.  But too many tempt you to use them all, and you can end up with mud.   You can get perfectly good greens by mixing either lemon or aureolin with either winsor blue or cerulean (see below for dark greens), and good violets and purples from the range set out above.  

Techniques for watercolour washes

Note that in the following suggested procedures, the most important  points are emphasized in bold type.

A key feature of a good watercolour is its clarity, a characteristic which is difficult to achieve when mixing colours to get the colour required.  Most colour mixes need at least two primary colours to be mixed to arrive at the desired secondary colour (for example, a green, purple or orange), and a common problem is that muddy colours result unless great care is taken in the choice of the primaries (the red, blue and yellow) used.

One way to keep clarity is to avoid mixing colours on the palette, but rather to "leave it to chance" to determine how a colour is arrived at.  By chance, I mean the random effect of allowing primary colours to "swim" into each other on the painting surface.   This can best be done by painting an area which is to be, let us say, green foliage, with a moist wash of clear water (just a little water, so that the strength of the colour applied is not reduced too much).  Before the water has a chance to dry, touch in some yellow and let it "swim" around inside the borders of the wet wash, and then clean the brush, and pick up some blue paint (not too much!), and touch the brush into the wet area - not necessarily where the yellow is most prominent.  These two colours will blend where they meet, and produce subtle greens.  Depending on the green effect required (for example, whether it is distant trees, or foreground grass), some warmer tones may be needed, particularly in the foreground details, and here a touch of red or burnt sienna can be added judiciously to the still damp green area. 

It has to be emphasised that practice is needed to get this technique right, so the amount of water in your first "moist wash" has to be just right, something that can be affected by the temperature and humidity where you are working.  Also, the amount of water you have in your brush when you pick up the yellow and blue paint is equally important.  So practice getting the effect you like before using this method on your masterpiece in the making!

It is important to allow the resulting area to dry before starting to overpaint it with extra colours.  The drying process can be accelerated with a hair dryer (if you are working indoors), otherwise you need to be patient.

One way of practising is to try out this process by sketching a summer tree outline and washing it with clear water, then adding colour as described above.  Remember not to stir the wet area around, but leave it to find its own mix of colours. 

Watercolour painting technique reminders

Remember that while watercolour is a popular medium to for developing painting  skills, as it requires few basic materials -  paints, brushes, paper and water, and it is a clean medium, with no unpleasant odours or extended drying time, ideal for outside work (unless the weather is very hot, when its tendency to dry quickly can inhibit the painting process), it can also be a difficult -- perhaps the most difficult -- medium to master, as the technique of getting the right density of paint (the value or tone) with one application is dependent on a range of factors.  The paint, whether from a tube or a pan, normally has to be diluted with water (except for the rare occasions it can be applied undiluted from the tube), and the quantity of water can be critical.  A watercolour wash can be very wet, moist, damp or "dry" (ie. applied to dry paper).  At the same time the paper can itself be wet, moist, damp or dry before the paint is applied, and the ambient temperature and humidity will always affect the length of time it stays that way.

So considerable experience is necessary before a totally satisfactory (to the artist) painting can be completed.

Some points to bear in mind when painting a watercolour masterpiece! 

  • Use a reasonably large mixing palette, and squeeze out a generous amount of paint.  Too small a palette doesn't allow enough room to dilute and mix your colours, and too little paint can lead to insipid tones in your painting.
  • Think about the range of colours you plan to use, especially the blues and yellows, since these are crucial in the production of clear greens.  For example, mixing French Ultramarine Blue with Cadmium Yellows does not give the clear greens you get with Winsor Blue (Red Shade), or Cobalt Blue, with Lemon Yellow or Aureolin.
  • It's a good idea to make a colour chart of your own, particularly of the colours you like to mix greens.  Try various combinations of blues and yellows, and add some browns/reds to the mixes (burnt sienna, burnt umber and even cadmium red).  A touch of burnt sienna will tone down the rather acid green which results from Winsor Blue and Lemon Yellow, and mixing burnt umber with a green can give a really deep dark green for shadows.
  • Remember the importance of WATER in watercolour!  Use plenty when diluting your colours, especially when laying in your first washes.  Experience will tell you how much water to use for first washes, and when painting detail:  try out the effect on a piece of spare watercolour paper (the same as you are painting on) before painting on the main picture.
  • Do not over mix your colours on your palette:  stirring blue and yellow together until you have a uniform green, however clear it is, can result in a dull painting, and it is better to keep your pool of blueish and yellowish green varied so you can dip into different hues of green as you work. 
  • Try painting a landscape features as a clear wash of water, then drop in touches of colour (including pure primaries - blues, reds and yellows) and allow them to blend naturally on the painting while keeping the various colours fairly separate until the paint starts to dry.  You can then touch in stronger colour where you feel it is needed.  this gives a more interesting and eye-catching result than "flat" secondary colours.
  • Avoid "dabbing" colour with the point of your brush: sweep the colour on with the side of the brush, and try applying it with less water and an up and down motion, to add texture to the painting.  Only use the point of the brush when painting details, usually when your washes have dried
  • Avoid a spotty effect when painting distant trees, as less detail in the painting of them gives a better feeling of distance.
  • Try adding some Gum Arabic to your foreground details and focal point, as this makes the paint dry a stronger and more brilliant tone, which can transform your contrasts.
  • Remember your paper can be wet, moist, damp or dry depending on how much water you use, and this condition changes with humidity and as the paint dries.    
  • Draw as accurate a picture as you can before you start to paint, but don't be too careful about keeping within your pencil lines.  Stay loose!

Painting river scenes

The picture on the left is a quick colour sketch of a Wareham scene:  I suggest this type of scene is best be tackled is by roughing in the three main 'objects' (the bridge, the small building in the centre, and the church), on an eye-level line one-third up from the bottom (not across the centre of the picture as in the photo), and bring the left-hand path round so that it sweeps towards the centre of the picture at the bottom, thereby becoming a feature which leads your eye into the composition, rather than running up the left side of it as in the photograph.  On the right, is a slightly more finished treatment which suggests the contrasts which should be aimed for in any painting.

River scene 1River scene 2

This subject was discussed during a TAG meeting, when the problems of getting really dark greens into paintings was raised, and I suggested that, as outlined above, it is worth trying the system of applying  clear water wash, then  after applying colours unmixed into the wash then dropping in a second colour (such as blue into a yellow wash), and allowing the colours to blend naturally on the painting, a darker green can be achieved by adding a brown (burnt umber or burnt sienna) and/or a violet (winsor blue red shade plus permanent rose of alizarin crimson) to the mix.  Allow these added colours to 'swim' a little, without stirring them together on the paper, so a variety of colour is visible:  this gives an "interesting" colour range, which is an improvement on the flat green which results from mixing a blue and a yellow in a dish or on your palette.  I suggest (again!) you use Winsor Blue (red shade) and Aureolin or Lemon Yellow, as other blues and yellows do not mix so well to give clear greens. 

Finally, try something of your own choice!