U N D E R P A I N T I N G:

There are several ways to go about your underpainting- also known as the first layer of your oil painting process. The underpainting is the most critical part of your piece as it is the foundation for all other layers to follow. It is where you establish your composition, and values. The method of underpainting will become a personal preference depending on your individual strengths and weaknesses as well as what your personal goal is for the finished product.

Almost always an underpainting is done in one colour.The colour used for an underpainting varies upon the technique being used and the painters requirements.

By painting the piece monochromatically first it allows you to focus on values, lighting, composition and form (the more critical elements to achieving believability and a strong painting). By leaving the colour out of this stage, you can focus on the foremost important areas of concern, while then tackling colour separately without divided attention. This means when it comes time for the colour application, it has your full attention, and you will be much more inclined to apply correct tonal shifts that adhering to correct values and form. This decreases the chances of having to make corrections related to light, form or composition later in the painting when it will be most difficult to correct.

Some underpainting techniques include:

The most common underpainting technique is an umber wash across the whole canvas.

Start by staining the canvas with an earth tone such as raw umber. You can do this a few ways- either by by taking raw umber and smearing it directly on the canvas from the tube. Then use a cheap cloth dabbed in some odorless solvent to wipe the paint all over the canvas (don't be a twat- WEAR GLOVES!).The result is a coffee-stained appearance.

Then make inconsequential strokes with a brush to help get a feel for where things will be positioned. You can also lift up the umber with a dry rag to block in your lighter highlight areas.

Then wipe the canvas down so that there is no excess build-up of paint. You want this layer to be thin so that it dries quickly.

Do not mind if there are different textures and brush markings on the canvas as this creates an interesting surface to paint on, especially if I am painting a landscape. If you were to paint a realistic portrait, then you may want to ensure you have a more smooth and consistent surface. (This is one technique-though most common- is not one I personally use)

Another way to approach an umber underpainting is once you've sketched it on with pencil, start painting your piece monochromatically in umber only. (I only do this to the parts of the painting I know I'll need it) You can use OMS here but, but since I prefer not to use solvents, I either dry brush it on our use a small touch of Galkyd or Liquin if I need it to glide smoother. The finished underpainting is a coffee coloured version of the final painting. I can then use a combo of dry brush, glaze, or thin paint application over to render it fully in colour layers. This gives me incredible believability in depth, value and tone. 

Here's a look at a painting I completed using this technique.

 

Grisaille is a monochrome painting executed entirely in different shades of gray or a grayish tone.

'Gris' is a French term for gray. Paintings in a brown scale are referred to as brunaille and paintings in a green scale are referred to as verdaille.

Grisaille was typically used during the Renaissance period as a stand-alone painting technique to imitate sculpture, but it can also be used as a preliminary painting stage, where the grisaille forms an underpainting which can then be glazed over once it is dry. Glazing technique is best to follow this underpainting since so much care will have gone into perfecting your rendering that to cover it with more opaque paint layers would be redundant. This of this technique as pretty much finishing a painting in black and white/grey scale perfectly to then tint it with colour after. It is the longest most precise underpainting but only effective if glazing tints over a monochrome piece is what you're after. This can be great if you are painting a piece (say a verdant landscape) that you really want to transcribe light to. However it would take many many glaze layers to achieve a nice affect, though tedious it would produce rich and beautiful luminous results.Rendering a grisaille underpainting to perfection  to follow with strictly glaze technique is not a very common choice.

There is a more common use of this technique in which you paint in grisaille but looser with the intent of covering it in opaque colour, and even though you the underpainting won't affect the final product, this is more for the confidence of the painter... if you struggle with getting correct values, this could be a beneficial grisaille technique. 

I've formulated another take on the grisaille underpainting-  tweaking the underpainting process to suit my needs. Here's how:

-first step is to paint the whole canvas in a medium grey tone

I chose to use medium grey acrylic paint as my base. I do this b/c I am a portrait painter and getting accurate skin tones and believability is critical, and a medium grey base is the best way to see colour and assess proper skin tones going down. (paint the same colours on a white background, a grey background and a black background, or any other colour background and you'll see they all appear different even though it is the same colour. Grey keeps it truest to tone.)

 -Then used the oil dry brush technique to block in the deepest shadows.

- I then roughed in all my lightest highlights using a white acrylic. I chose to use acrylic white b/c I want my highlights to be the most textured area of the painting, so when the light hits it, it catches those highest peaks and makes them stand out even brighter. (you want your shadows to be your most flat areas and your highlights to be the highest texture on the canvas) And since these highlights are textured, if I were to use oils, it would not only take a long time to dry, but break the fundamental 3 RULES of oil painting. Since my base was a grey acrylic, its safe for me to use acrylic still. Since you can put oils over acrylic but not acrylic over oils, this is a great way to utilize the mediums. Another reason I wanted my highlights to be raised was that I knew I was going to paint over the majority of them in the layers to follow, and I wanted to be able to easily find them again. Unlike the shadows that got less paint and thinner paint applications over them, the darker underpainting areas you can see through easier than the highlighted areas. It's easier to cover white than it is to cover black (think of when you're painting a house... it's no trouble to paint colour over a white wall, but complete hell to paint over black without it showing through.. it takes a lot more layers to cover that black.

One of my weaknesses as a painter is I tend to zone out and get lost and render without attention, and so for me I find it easier to mark reference points out in early stages that I then find and use in later layers to make sure I'm on target compositionally to make sure nothing is getting out of proportion.  So I use this underpainting technique to highlight these reference points like moles, or highlights ect.

Heres a look at my technique and how it comes together. (keep in mind this was my first hyperreal portrait painting, and first time experimenting with my technique

Here you can see the painting on the LEFT and the photo reference on the RIGHT to see how my points of reference and highlight and shadow areas aligned. as well as how accessible achieving skin tones was with the neutral grey background.

As Time went on, I very quickly realized values were one of my strengths and no longer needed to spend time focusing on those too much in my underpainting, so I omitted mid-tones and just plugged in my darkest darks and lightest lights. Keeping the rest of my technique intact. Here's a video that shows the progression of one of my paintings using this technique

Similar to the umber wash underpainting technique is to do this but in a specific colour that relates to the over all affect of your painting. The colour of your underpainting sets the tone for the final piece. So feel free to utilize this in ways unique to your practice or style. 

Here's an example of a piece where I painted the whole canvas in a dirty chartreuse/green colour to give the paint a gritty grimy feeling in the end.

In progress

This is one of the works I ended up cutting up (part of a series), so this is the only photo I have of it showing the final painting look using that raunchy green underpainting. You can see how bits of it resonate through to give a feel and affect to the finished piece.

The last underpainting method I'll get into is one I employ most often these days. If the canvas is white, I'll paint it all a neutral grey with acrylic first. Otherwise I get clear gessoed linen, so it already is a neutral warm beige/grey tone to act as my base.

I then go in with my base tones and do a thorough colour block in (first square). making sure I use colours that are lighter in value than what I want my final piece to be, and making sure I lay down tones that as I blend them together, they become less saturated than how I intend the final result to be. Since I can easily add saturation and value, but cannot undo saturated tones or lighten value with glazing, I always play it safe and shoot just under. so when I'm done blending it (second photo) it is a smooth, lighter, less vibrant version of the final piece. 

The third square you see is the result of the the next layers to follow after my underpainting in square two was dry. 

It takes several layers after this initial colour block in to get to the final result. 

This method will be more difficult to execute well in the early stages of learning to oil paint. It requires a well-rounded understanding of value, tone, and how your paint interacts with itself in its wet layer, as well as how it will come to be when planning future layers, and how it reacts over dried colour layers. The way colour interacts when wet on wet, vs wet on dry, vs glazed  is all different. You can learn more about understanding colour in the UNDERSTANDING COLOUR tab