Whilst I have added extra tone to the mouth and teeth, the shadow section of the face and the dark underpainting to sections of the coat, I was not feeling that the portrait itself was as close a resemblance as it should be.
I pinned it down to the shape of the cheek and chin and so, I adjusted the profile in this area. It will still need a little refinement when dry but I am much happier with the adjusted profile. The lower picture is the original and the upper one the adjusted one.
I think that part of the problem in seeing this is the fact that, although it is a portrait, it is not a conventional upright pose. Note to self: rotate the painting occasionally to view the image in a conventional upright pose.

 I have added some colour to the mouth which helps to convey the expression.
Darker flesh tones have been added over the pale underpainting which can be seen more in the lower photograph.
I am now beginning to enjoy this painting. I am always a little apprehensive when I start a new work which is probably why I am such a slow painter!
There are many tones and details to be added in the hair and face yet, but I may under-paint the coat/jacket in my next session which is the large area just below the mouth. This coat casts a shadow on the lower part of the face which will be an important part of the composition and will add dimension.

The shadow area is mostly blocked in. The colour is very neutral at the moment, and will need a number of layers to achieve the right tone.
The tones will need to suggest the perspective, as the top edge of the face will need to recede into the background.
As an artist, even with experience, I am always anxious that the painting is a success.

The underpainting to the hair is quite textured with crude brushstrokes, but this is intentional, as when the hair texture is added it will provide the variety of tones that occur in reality. Even areas of highlight over the top of a darker background will add 'depth' to the image.

 
Slow progress, as I have been busy with garden landscaping, but I have added more detail to the right eye. I shall add the underpainting to the hair area next as I work my way around the head.

I am adding some of the basic flesh tones in the lit areas but more contrast will be needed as it progresses. I have a W&N preprepared flesh tone but only use it to add to the whites and yellows to make a basic flesh colour of my own. When I want to deepen it I also use Burnt Umber, Alizarin Crimson and a green biased blue. The use of complementary colours in facial shadow is well known, and, in some modern portraits, exaggerated to great effect.

I have added some flesh tones around the right eye and will continue along the right side of the face which is lit. The left side of the face will be in shadow.
The tones are only a first rendition and will have to be adjusted as I go along

Even though I am doing another portrait of Christopher, I decided to post a slide show of the progress of my last portrait of him.

A short 20 minute session today.
With a portrait, the eyes are the 'window' to the character and personality. They show what the person is 'thinking'. This is why I like to block in the pupils of the eyes early in the painting process. Naturally, once dry, I shall refine them in tone and colour.

The book is becoming apparent now even though the coverage is just the under painting.
This is a square painting but I have still tried to make the composition stable with a suggested triangle using the book as the base and the face as the rest of the triangle.
There will be a band of sunlight across the composition from right to left lighting the top of the book and the lower part of the face.
Having the top of the face in shadow will add dimension to the portrait. I haven't decided, yet, how dark the shadow will be.
When I am beginning a painting that I find challenging, I take a long time looking at it, and thinking about it between sessions and, if I am truthful, I am always a bit anxious about it being a successful work.

I have finally put paint to canvas. I was unsure with this composition, where the subject is lying sideways whilst listening to a story, but I like the 'gravity' that the book provides at the bottom. The background will be much in shadow, as will the book itself. The only hint as to which book it is, will be the colour.
The teeth are showing, as the mouth is slightly open, but they will not be as prominent once the paint tones are applied. He is wearing the same jacket as in my previous painting of him, which makes great contrast of texture with the smooth flesh.