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Opaque and Transparent Colours: Acrylic

March 30, 2020

This is the first of my art challenges for Art Challenge Tuesday which I hope to publish every Tuesday on this blog.  Hopefully it will be a good way to cheer everyone up till we can meet again face to face.  I have been running a course on watercolour and acrylic glazing techniques for my group at Norden Farm and will be running a similar course in the autumn for another group.

Sadly the isolation rules came in half way through the course, so the project below exploring acrylic glazing techniques has already been sent to that group by e-mail.  Below is a bit of a recap plus a few of the things we would have explored in the remaining Tuesday sessions.

Magic Pear: monochrome under painting in acrylic

 

Magic Pear: glazed with alizarin crimson, azo yellow and ultramarine

 

Acrylic: Opaque and transparent colours

To explore grisaille (working in monochrome) and glazing techniques we have been producing under paintings in greyscale and then adding layers of transparent glazes to colour them.  It’s obviously important to know which the transparent colours in your box are, so here are a couple of things you may like to try.

Number one may be a bit basic for some of you but have a look and do what you feel like attempting.

 

  1. Opaque and transparent colours

To find which paints in your box are transparent

Paint half a small sheet of thick paper with black and half with white.

Paint a stroke of colour across the white and black.

Opaque paint will obliterate the join where black meets white.

Very transparent colours that contain no white will almost disappear on black making the surface look rich and shiny.  Dioxazine purple and phthalo blue and green will do this.

However they won’t if the tube also contains any white.

To keep working transparently always mix your transparent paints with medium or water NOT WHITE.

Most yellows are either opaque or translucent.  Translucent colours become more transparent when diluted.

 

Judging how much to dilute pigments for glazing.

Sometimes you will require quite an intense glaze and at others you will want just the merest hint of colour to tint your painting.

You can practice different strengths of pigment by glazing on newsprint that either has text or greyscale images.  You need only glaze small areas but if you have time do glue the newsprint down on a sturdier piece of paper first with some acrylic medium.

When dry paint over with acrylic colour.  Try different colours and make a note of which colours are transparent when dry.

Diluting acrylic paints;

Do the same thing with more dilute pigments.

Dilute with water or acrylic medium.

Medium makes it easier to blend pigments and to control where the paint is laid down.  Acrylic mediums usually appear milky when wet but dry transparent. Diluting with water makes the paint behave more like water colour.

Always add a tiny amount of paint to the medium or water not the other way round or you may waste a lot of paint.  You can always add more but generally you won’t need as much  paint when you are tinting an underpainting than when working in colour from the start.

These are experiments so can be done on a very small scale.

They will help you find the right paint dilution for your purpose.

You can also experiment with overlaying different colours but always ensure one layer is dry before adding the next.

 

  1. Subtle and bright glazes

3a. If you have access to a photocopier you could photocopy a landscape or room interior in greyscale on to watercolour or other substantial paper.  It would be great to make two copies of the same image and glaze one in a very subtle way with very dilute glazes and a much more vibrant version with bolder colours and some more concentrated colour.

It is always best to use your own photos if possible.

After Hammershoi: acrylic under painting from sketches made at the RA

After Hammershoi: with very dilute glazes of alizarin, raw sienna and transparent burnt sienna

3b. Make two similar under paintings in greyscale for a simple composition, then glaze with colour to produce a subtle version and a more vibrant one.  Take care with the tones in your under painting.  Think about the fact that every time you add a layer of transparent paint that area will become darker.  Make sure you paint some white areas for the palest glazes and any areas that will remain white.  However, with acrylic if you haven’t got the tones quite right you can always repaint with white or the right shade of grey and add more glazes.

You could choose to make your versions of a Matisse interior for this exercise; judging the tones will be a challenge.  Or you could make your version of a Hammershøi interior.  His paintings are very tonal with very subdued colour, so getting the under painting right will be much easier.  It would be a good exercise to do one version with subtle glazes echoing Hammershøi’s use of colour, and a second with vibrant glazes of bright transparent colours.  Remember in either case you can glaze part or all of the painting and you can further modify the colour and tone by overlaying glazes.

The response: Your Paintings

Monochrome Under Painting and Same with Transparent Glazes

 

Sunflowers in a Basket: Acrylic under painting and finished painting with glazes

John was has added white to the petals and reglazed with yellow to make the flowers brighter. With acrylic it is always possible to modify your painting in this way, so if your colours look dull you can go in with a paler tone and reglaze, and you can modify again with further glazes of the same or a different transparent colour if shadow areas are needed where you have already reglazed.

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