Possible Clues:

• Tune: primarily audiovisual artist's medium
• Outburst of anger over a painting
• Artist's medium or moderate ability, initially
• Way of painting causes a tantrum
• What's used for painting sacred building, with pounds spent on artist
• Soften a medium for artists
• Casual period that may be useful to artist
• Soften a medium
• Method of painting; emulsion
• Ruler wanting gold colour put in appreciated painting method