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The success, value and durability of a painting are to a great extent determined by good planning. This entails the following general guidelines:
- defining the idea in concrete terms
- determining the quality of the given or chosen support
- checking on need for priming or pretreatment, which depends on the quality of the support and the type of paint to be used
- selection of suitable colours and painting mediums
- choosing the painting technique
- preparing the colours ( e.g. thinning, thickening, improving adhesiveness, amount, etc. )
- deciding on a special protective final coating ( varnish, sealer )
In this planning phase there are, of course, a number of other factors to be considered, such as for instance external conditions ( weather, temperature of the substrate, local conditions, time allowed for completion ), proper tools, containers, auxiliary installations, accessories, etc.
The physical properties of the support and the pretreatment of the ground determine the durability and permanence of the work, as a painting is only as durable as its substrate or base. Application of acrylics onto traditional supports such as canvas, cardboard and paper etc. proves largely unproblematic. Such supports can be painted on directly without special preparation, keeping in mind only a few basic principles about priming, acrylic colours application ( e.g. open time, retarded drying ) and painting techniques.
The following information concentrates on mural paintings on different surfaces making particular demands that must be dealt with in a professional manner if the success and durability of the painting is to be ensured. The following are some basic guidelines which should always be considered about the supports and grounds when painting with acrylics or other paint:- never paint on alkaline grounds.
- surfaces must be clean, greasefree and dry in order to ensure good adhesion for subsequent coating.
- walls in wet-rooms are problematic regardless of the ground, due to environmental physics.
- the
substrate should be compact. It should neither crumble nor flake, and when old
coats of paint are painted over the surface must not be prone to peeling or
chalking. A priming coat will only stabilise the thin exterior layer without
penetrating into deeper layers. Chalking or crumbling supports can be
stabilised to some extent by first applying a penetrating sealer. However, this
is impossible with surfaces that are already loose and starting to
disintegrate. In such cases, the first step is to re-establish a sound painting
surface by removing all the loose material (by knocking it off, scratching it
off, brushing it off etc.) in order to create an even, stable surface for
filling and smoothing with plaster, cement or concrete, in order eventually to
seal it evenly.
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too smooth substrates or surfaces covered with layers of old, oily paint and varnish, should first be roughened with a weak ammonium hydroxide solution and if necessary treated with a wash primer.
- metal surfaces must be free
of rust and grease. Ferrous metals should be primed with a matt, synthetic
resin antirust coating.
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the support should always be tested for absorbency. Porous or unevenly absorbent surfaces should be sealed with diluted acrylic paint or primer. The basic rule is:
the more absorbent the surface, the thinner the first coat should be in order to ensure proper adhesion.
A second layer can be applied, depending on covering power required. When the primer is applied without sizing on a support directly, it needs to be diluted with water in a ratio of at least 1:1 ( except when prone to bleeding ). Acrylic colours can also be applied directly to the sealed support. In this case the colours must be diluted already for the first coating, as this will replace priming.
Wood needs to be completely dry and pollution-free ( sanded off or washed with solvent). To prevent warping we recommend sizing front and back sides with Lascaux Transparent Varnish 1 gloss, diluted with water at a ratio of 1:2 up to 1:3 (in order to avoid distortion) and eliminating protruding fibres with fine-grained sandpaper. Surfaces can be painted onto after sizing or after adding an additional coat of Lascaux Primer, Gesso or Studio Original White, in each case diluted with water to 10-25 %.
Fresh fairfaced concrete must be clean and dry ( max. 2-3 % of residual moisture ) before it is suitable for painting. If a wooden formwork was used, the concrete must be cleaned with a brush or, better, a pressure washer, in order to remove loose concrete, burrs, wood splinters and traces of formwork oil. Concrete with a very smooth surface, especially the plastic or metal formworks variety, should be cleaned with special care. If necessary, perfectly smooth surfaces should be roughened with fine sandpaper.
Paraloid B72-10 % or Lascaux Hydro-Sealer can be applied, diluted with water at a ratio of 1:4 in areas with special requirements such as bathrooms or outdoor spaces. Subsequently apply one or two coats of Uni-Primer, diluted with approx. 10 % water, or Studio Original White 982, diluted with 10-25 % water. Exterior painting on fair-faced concrete can be treated either with a fresco technique or prepared as follows: sizing with Lascaux Hydro-Sealer, diluted at a ratio of 1:4 with water and then apply one single coat of Lascaux Medium 2 matt diluted by 25 %. This treatment prepares the concrete surface without altering its matt character or colour. The sized surface is then ready to be painted with acrylic colours or gilded with Mixtion gold leaf.Pure lime mortar takes a long time to set and has a strong tendency to crack. The ground should first be allowed to dry thoroughly, then be rubbed down with a piece of wood in order to remove loose sand particles. The next step is to apply a single coat of sizing with Lascaux Hydro-Sealer, diluted 1:4 with water. After this a single coat of primer is applied by using Lascaux Primer or Lascaux Studio Original White 982, each diluted at least 25 % with water. See also the chapter «Fair-faced Concrete».
Lascaux acrylic colours exhibit good adhesion on a variety of non-absorbent synthetics such as acrylic glass, polyester, PVC, melamine resin etc. Please note that adhesion is very poor on polyethylene and polypropylene.
Surfaces should be sanded carefully and subsequently cleared of grease with e.g. methylated spirit. For white priming we recommend Lascaux Uni-Primer, whereas for transparent priming use Medium 1 gloss. When painting mix Lascaux acrylic colours with Medium 1 gloss or Transparent Varnish 1, gloss at a ratio of 1:1 up to 1:2 which increases adhesion even further.
It is always advisable to enhance the durability of a work and protect it from possible damage by varnishing with a sealing agent even when acrylic colours dry to yield a water- and weather-resistant finish. A suitable varnish effectively protects acrylics against dirt, mechanical stress, light and weathering.
For indoor applications Lascaux acrylic varnish will be sufficient in most cases but with strong exposure to UV rays and for outdoor applications it is recommended to seal surfaces with Lascaux Transparent Varnish UV. Non-water-resistant paintings can be protected against wear and corrosion by spraying with Lascaux Fixative ( light protection and little change of surface ) or varnishing with Lascaux UV Protect spray ( homogeneous film, strong protection against mechanical stress and UV exposure, possible changes in the appearance of the surface ). Please note: UV Protect spray and Fixative spray need to be applied in very thin layers. Follow instructions in video or on spray cans.
If a painting ever gets damaged, we recommend consulting Lascaux before attempting any repairs on your own or contact a restorer directly.
Once dried, Lascaux acrylic colours are not soluble in water, but can always be swelled in alcohol (methylated spirit) and other solvents. Lascaux Gouache Colours dry to a water-soluble finish.
Removing paint spots from textiles is problematic, as all pigments exhibit a special preference for textile fibres. However, often stains can be removed from clothing using liquid detergent applied directly by means of a compress. Hard-dried brushes should be cleaned with Lascaux Brush Cleaner and then washed with water and soap.
Lascaux Colours are well suited for the airbrush technique. Depending on the result desired and final purpose for the finished object several ranges with water-resistant finish are available: Lascaux Artists’ acrylic colours, Studio Original, Sirius acrylic colours and Perlacryl. If water-resistance is not a prerequisite nor desired, one can choose between Aquacryl, Sirius Watercolours, Gouache and Decora.
Airbrush is a demanding technique which requires the utmost care and attention to the cleanliness of tools. Nozzle size is chosen based on the desired outcome, however, it should not be any smaller than 0.15 to 0.5 mm. Additionally the right balance between pressure, nozzle opening and dilution determines the results. It is always advisable to mix a sufficient amount of paint and to have the colour readily available as remixing of a specific hue might prove difficult. We also recommend sieving the paint to eliminate extraneous particles.
Lascaux acrylic colours need to be diluted with water until they reach the desired consistency appropriate for spraying. Add water in small amounts and stir with a continuous motion. The paint’s consistency is determined by the size of nozzle and selected air pressure. Dilution ratio can vary between 1:1 to 1:3 paint/water. Dilution can also be achieved by mixing Lascaux Transparent Varnish and water at a ratio of 1:1 to 1:4 which results in extended work life and delays drying of the paint on the nozzle. Highly diluted colours have a tendency to settle and must therefore repeatedly be stirred well.
You can buy special pouring mediums if you wish – but you don't need those if you have the Lascaux Transparent Varnish at hand. Together with some Lascaux Studio acrylics and a bit of silicone oil you are ready to go.
Our instruction leaflet guides you through the process.