Chroma’s Jo Sonja Crackle Medium is a transparent medium, which causes Chroma’s Jo Sonja Artists’ & Background Colors to separate into fine cracked or crackled patterns in a one step process. Use to simulate the effects of aging. Recommended for use with Chroma’s Jo Sonja Artists’ & Background Colors only. We suggest you test your technique before committing to a project.
Directions: • Apply a thin coat of medium for fine cracks, moderate coat of medium for medium cracks, thick coat of medium for large cracks.
Background Crackle: • Prepare surface by sealing and applying basecoat. For one step preparation, mix All Purpose Sealer and the basecoat color beginning with a ratio of up to 1:1 for the first coat only. Allow to air dry and lightly sand. Apply additional coats without the addition of All Purpose Sealer. • When final basecoat is dried to touch, apply Crackle Medium working a small area at a time with brush suitable to surface size. Work quickly using a criss-cross motion to apply Crackle Medium. Slightly blend out the brushstrokes as you apply the medium. The crackle pattern will follow the direction of the brushstrokes. Do not brush back over previously applied medium that has started to dry as doing so may cause the Crackle Medium to lift. Crackle Medium will level out slightly as it dries and will dry clear. • Allow to air dry undisturbed. • Crackle Medium is formulated to separate into a cracked or crackle pattern as it dries. Paint layers that have dried but not cured may also separate. The thicker and fresher the paint, the deeper and cleaner the crackle pattern will be. DO NOT USE A HAIR DRYER between coats of base color. Warm air will cure the paint and prevent the crackle from working properly. The base color will show through the crackle pattern if an uncured contrasting color is applied before the application of the Crackle Medium. • After crackled surface is completely dry, gently sand surface using #400 to #600 grit sandpaper until desired smoothness is attained. Wipe to remove dust. Any that remains in the crackle pattern will disappear with antiquing or glazing. • Crackle Medium will leave surface slick. Pattern application may need to be modified. Light sanding should decrease “slickness” of the surface. • Antiquing may be applied to the surface to accentuate the crackle pattern. If painting is applied over the crackled background, 1-2 coats of Clear Glaze Medium may be applied as a barrier coat. Thin contrasting color with Retarder Medium and brush into cracks. Remove the excess with a soft cloth moistened with Retarder. • Allow to dry completely before varnishing. A coat of Clear Glaze Medium is recommended prior to varnish application.
Variations: • Crackle Medium can also be applied after painting the design or over photocopies or prints, which will produce fi ne crazing for an aged effect. A coat of Clear Glaze Medium is recommended prior to crackle application. You may choose to antique the surface to accentuate the crackle pattern. A light sanding before antiquing is recommended.
Approximate Coverage: 1 ml = 62 sq cm / 1 oz = 2 sq ft