Acrylics Articles - All you need to know about Artists' Acrylic Mediums

We can all appreciate that when asked, most painters would say colour is the most important element of their materials and of course it is. However, colour is not enough; many painters want to be able to push it further, develop it, manipulate it and make it their own. That’s where mediums come in…

It is not often that we have the opportunity of re-thinking mediums from scratch but that’s exactly the chance we had following the introduction of Artists’ Acrylic Colour – a range of the strongest and brightest colours which no longer suffer from colour shift from wet to dry.

Using our new colourless binder we have breathed new life into acrylic mediums and have produced a concise range of 14 acrylic mediums which do not overlap, making it easier to choose and use them from the start of your painting until it is completed. Using these mediums with Artists’ Acrylics continues to maintain their colour brilliance and avoids suffering any colour shift whilst painting.

In this article we are going to look at each medium and investigate both the common and more unusual uses of the mediums and take some notes on the things to avoid too.

There are no rules with Acrylic Mediums

Unlike oil, acrylic paint films are more or less equal in strength and flexibility regardless of the pigment used. As a result there is no ‘fat over lean’ rule in acrylics – you can use any colour in any order with or without medium. As the colours dry at generally the same speed there are no rules either about thickness of film or drying rates. This makes painting in acrylics easier technically than oils – it is pretty hard to have a painting process problem in acrylics! This leaves you free to use mediums purely for how they change the colour and give you the effect you want without having to worry about ‘rules’.

Choosing and Using Acrylic Grounds, Mediums and Varnishes

The labels on our new Acrylic Mediums use a table device to show the characteristics of the product and this comes in really useful when wanting to compare mediums as well as when initially choosing in store. We have also developed a usage map to help you choose the product you need according to the effect you want to create.

Click here to see a full sized label

Artists' Acrylic Mediums usage map helps you choose the medium you need 

Notes and Advice on Artists’ Acrylic Mediums  - read through the complete article or click on the area you’re interested in:

Grounds & Primers
Mediums
Structure
Additives
Varnishes

Grounds & Primers

Grounds or Primers provide a sound structural base for your painting. They allow the control of the colour, texture and absorbency of the surface.  You can paint directly onto the support with straight colour rather than primer, as acrylics are made of larger molecules than oils and therefore the binder in the colour does not sink into the support as happens in oil colour. If you like painting straight on linen then acrylics are much better than oils for this reason. Otherwise, we would recommend the use of primer, the colour adheres well to it and it strengthens the support. In the very long term when the canvas embrittles and wears on the corners of the stretcher, a primer supports the painting during the relining process.

The quality of the primer is important. There is no point using artists’ quality colours on a DIY/ household paint. These are simply not made to last! Even within the artists’ materials industry this is the area where we see the poorest quality products. Winsor & Newton primers are as carefully formulated as any of our colours.

White Gesso
This is highly opaque, often one coat will be sufficient. Gesso can be used on any surface as long as it is not greasy nor too smooth. It has a good degree of tooth, essential for good adhesion between the ground and the colour.

You can paint on it in acrylics as soon as it is touch dry but for oils allow 24 hours before painting. Painting on white originated with the Impressionists who wanted the colours to remain as bright as possible.

Sometimes however, a bright white new canvas can be intimidating. You can resolve this by applying a dilute wash of a colour of your choice, often earths or greens, across the canvas. This will maintain the brightness of the white but brings the tones of the painting together more easily and allow you to retain the tooth of the primer.

If you prefer an even opaque coloured ground then mix your chosen colour into the primer first. The colours will be less bright but easier to control.

White Gesso on Canvas: (a) Transparent wash on White Gesso (b) Opaque tinted White Gesso

Clear Gesso
This is an unpigmented primer. Winsor & Newton were the first to make this type of primer to help painters who wanted to avoid a white priming and to allow primers of stronger colours.

So for oil painters you can use Clear Gesso straight onto canvas instead of sizing and your painting will be much more structurally sound. You can use any colour but if you want an even surface then opaque colours are recommended. Use up to 20% colour to maintain the tooth of the primer.

Clear Gesso on Canvas (a) Clear Gesso on canvas (b) Clear Gesso with transparent colour (c) Clear Gesso with opaque colour


You can still use a dilute wash of any colour over the plain Clear Gesso if you want a weaker effect.

Clear Gesso is a life saving product for pastel and charcoal artists. At last with Clear Gesso you are able to prepare your own paper with lightfast colours rather than conventional pastel papers which mostly fade. Not only that but the tooth in the primer grips more pastel and reduces the need for fixative. We recommend you stretch your paper first.

Clear Gesso on paper: (a) Clear Gesso on paper (b) Clear Gesso with transparent colour (c) Clear Gesso with opaque colour


If you are looking at ways to economise in acrylic painting but maintain quality you might like to try either primer on stretched paper rather than canvases and continue using artists’ colours.

Mediums

The two main purposes of acrylic mediums are to change the consistency of the colour and/or its level of sheen. Using our new resin technology in all the mediums ensures the clarity of colour is retained and there is no colour shift, this is the biggest breakthrough in acrylics since they were invented more than 50 years ago!

Gloss Medium
This is the most popular of all the mediums. It is used by millions who just want the colour diluted a little and find water too watery. It improves flow and depending on how much you use will increase transparency. It is a high gloss which will increase the brightness of the colour. You can reduce the level of gloss by combining with Matt Medium.

Gloss Gel
This medium is the consistency of the tube colour so is ideal for those who want to maintain the texture of the buttery paint but want a gloss finish. It maintains the good peak retention of the colour. You can reduce the level of gloss by combining with Matt Gel.

Glazing Medium
Artists’ Acrylic colours are now softer and ‘oilier’ than other acrylics and this suits today’s painters. Many artists want to maximise fluidity but not at the expense of colour. Glazing Medium is a medium gloss pourable consistency which can be used to make colours flow right across the canvas and its increased transparency makes for excellent glazing in layers. However you use it, the colour will remain brighter than ever before.

If you want absolute colour strength with flow have a look at Flow Improver.

If Gloss Medium is the most used medium, Glazing Medium is certainly the most needed. Without it, artists who want significantly fluid colours will use water and this is not safe on canvas or board. Water alone will dilute the binder too much, leaving the pigment underbound and the painting dull and susceptible to damage. Although any of the mediums can be combined with water to avoid this, Glazing Medium is already the most liquid so you are able to maintain a higher pigment strength whilst reducing to the consistency you want.

NB. Acrylics on paper can have as much water as you like, (as per water colour) because the pigment is held in the paper interstices.

Cross section showing pigment trapped in paper interstices.

Matt Medium
This is the matt version of Gloss Medium. It is dead matt and remarkably, thanks to our new resin is free of the cloudiness of other matt mediums, even over black it has good clarity.

Matt Medium can be used for sizing if you want complete transparency. For example, sculptors may want to paint wood or plaster which is overly absorbent. Thin with 10% water and apply a thin layer. This also makes a good ‘fixative’ for any mixed media works which need a bit of gluing down. Use stretched paper to prevent any cockling and use a plant mister to apply a thin layer.

Matt Gel
This is the matt version of Gloss Gel.  Matt Gel can be used as an archival adhesive to replace PVA for any collage or artwork.

Take care with mediums:

• Bear in mind that using too much medium will produce a softer paint film which will trap dust and dirt.  If you find you are using more medium than colour then we recommend you varnish the work or keep it behind glass to keep it clean.
  
• Don’t use any of the mediums as a varnish for the above reasons. Medium layers are not removable and extremely costly and difficult to clean. If you want a continuous matt or gloss over the final painting then use our removable varnish.
  
• All of the mediums will improve water resistance a little because there is more binder to coat the pigment.
  
• If you want an overall Gloss or Matt (or Satin) finish on your picture you might prefer to paint with either water alone or your own ‘satin’ medium by mixing Gloss and Matt around 50:50. This will make colour matching easier if you rework the surface a lot. You can then achieve the finish you like with varnish.

Structure

Modelling Paste
Our new Modelling Paste is the whitest paste available. This retains brightness of colour. It gives good peak retention, is hard enough to be carvable and sandable but is still flexible. Thanks to more new developments we have achieved all this without producing a heavy product. This puts less strain on the canvas and the rest of the paint film.
It is a great product for sculptors too and is really useful for restoring small chips on ceramics.

We recommend that really thick layers should be built up by a number of thinner ones as there will be better adhesion and more thorough drying.

Additives

Flow Improver
This colourless liquid increases flow without changing any other characteristics. It helps with hard edge painting against masking tape because the colour flows up to the tape. For staining techniques with raw canvas it drives the colour into the fibres to increase colour saturation.  If you want the maximum colour strength from the tube but need just more flow, use Flow Improver.

Use Flow Improver sparingly (pre-mix with water up to 10%) as too much will interfere with the drying of the colour. For more dilute colour use Glazing Medium.

Slow Drying Medium
This retarder is water white and will double the drying time of the colours. This will give extra blending time on the canvas and also keep the colours ‘open’ on the palette for longer. For hotter climates it can be essential to make certain techniques possible in acrylic. For extending the drying time even longer, you could try the Compact Acrylics Palette which keeps the colours wet and you can also mist over the palette and canvas with water from a plant mister.

Slow Drying Medium can also be used with colours for screen printing by preventing the colour drying in the screen too quickly.

Do not use more than the recommended 1:1 ratio, as the colour will become soft and cheesy.

Varnishes

Winsor & Newton were the first to introduce removable varnishes for acrylics almost 30 years ago and we are still unique in doing so.  The varnishes are available in Gloss, Matt and Satin.

Most paintings are made to last, hanging for decades. Like all household things they will get dusty and the dirt will become embedded in the acrylic. You need to protect your pictures or they will become dull and lifeless the dirtier they get. They can be protected by framing with glass but this is not popular with paintings on canvas. You need a removable varnish so that the dirt collects on the varnish and then that can be removed and replaced, leaving the painting as good as new.

If the picture is thinly painted we advise leaving it to dry for a week before varnishing, for thicker impasto leave it for longer.

Our varnishes have improved water resistance to protect pictures from accidental splashes. The block resistance is good which means the harder film attracts less dust, keeping the painting cleaner for longer. The coverage is better than other varnishes which results in one coat being sufficient in many cases.

All the varnishes provide maximum UV protection, improving the lightfastness of digital prints and giclée work. Artists’ Acrylics are already lightfast but you could use it on lower quality colours to improve their permanence.

The varnishes can be intermixed if you want any degree of sheen in between those provided.

Take care with varnishes:

• Nice as they may be, don’t be tempted to mix the varnishes with colour. This will make the colour removable.
• Don’t dilute the varnish as this would prevent the coat from giving an even sheen.
• Don’t be tempted into using the varnishes as DIY/household varnishes, artists’ varnishes are made with relatively soft resins, making them too soft for handling.
• You will need Winsor & Newton Varnish Remover when you want to remove any of the varnishes.
• If you want to avoid conventional solvents when oil or alkyd painting, the varnishes can be used on oils or alkyds. Remember though a minimum of 6 months (3 months for alkyd) is required for drying prior to varnishing.
  

And finally......

If you find you are bitten by the acrylic mediums bug, don’t forget to look at the Galeria Mediums range. The texture gels can give a whole array of different surfaces and effects and Iridescent Medium will add shimmer to all your colours, to mention but a few!