Jo Sonja's Crackle Medium is a transparent medium used to create fine, crackle finish over completed acrylic paintings. This medium dries clear and will produce a 'cracked varnish' effect like that found on old porcelain. Once dry, this medium is intended to be sanded smooth and antiqued to highlight crazed areas.
• Prepare piece and paint in the usual manner. Allow to dry.
• Using a soft brush, apply an even layer of Jo Sonja's Crackle Medium over the surface where the crazing effect is desired. The brush should be used similar to a palette knife, laying on the medium instead of 'brushing' it out. After it is applied to the surface, overbrushing or reworking produces very fine, wispy crackles.
• Crackling will occur if room temperature is moderate to warm. Do not touch during the drying process. If surface is uneven when dry, lightly sand.
• Medium will be cured when completely dry. To emphasize the crazing, brush a darker colour thinned with either Jo Sonja's Flow Medium or Jo Sonja's Retarder into the cracks. Use a soft cloth moistened with Retarder to remove excess colour.
• Practice on a sample piece is recommended before attempting a project.
Thicker applications of Jo Sonja Crackle over fresher paint will create larger crackle patterns.
Cracking is not evident.
Possibly not enough medium applied or overworking of the medium. 'Spread' rather than brush across the surface, apply a generous amount. A good test is to pour some Crackle Medium directly onto your palette. Allow this to thoroughly dry. If the Medium has cracked then the product is not being applied thickly enough on your piece.
Crackle Medium dries unevenly.
Sand smooth when thoroughly dry and antique to highlight cracks. Uneven size of actual cracks is normal. If a more consistent result is desired, try to apply the medium more evenly. A ruler is useful for spreading.
Jo Sonja's Décor Crackle is a transparent medium to be used BETWEEN layers of Jo Sonja's Artists' Colours to provide a weathered paint or aged appearance.
The top colour will break apart to reveal the base colour. Metallic and Iridescent colours should not be used over Décor Crackle as they will not work effectively. They may however be used as base coat colours.
Pre-test varnish over Decor Crackle as some water based varnishes can reactivate this medium. Solvent varnishes may be used.
• Seal the surface with All Purpose Sealer or mix Sealer with your base colour. You may use tube or Background Colours.
• When dry, apply a medium-to-thick even coat of Décor Crackle Medium.
• Allow the Décor Crackle to completely dry; a hair dryer may be used.
• Apply a contrasting coat of Jo Sonja's Artists' Colours. This top colour will separate to expose the base colour.
Wide cracks will result from a heavier application of paint, finer from a thinner application. (The crackle effect will appear slowly as the top coat dries).
Jo Sonja's Décor Crackle is formulated to work with Jo Sonja's Artists' Colours. If using an alternate brand, particularly as the top coat, we suggest pre-testing to ensure compatibility.
Jo Sonja's tube colours generally give a better result than Jo Sonja's Background Colours. House paints in most cases are not compatible.
Once crackled and dry, if not sealed or varnished, water can reactivate Décor Crackle and cause it to blister and peel. If you wish to crackle a background and paint a design directly over it, we recommend a coat of Clear Glaze Medium to lightly seal before proceeding. Be light and quick when applying your medium or varnish and do not over-work.