Flashing or Sheariness The situations termed, both describe the glossy streaks or patches which sometimes occur, through faulty application, with flat oil paint, matt varnishes, and eggshell or semi-gloss finishes. Flashing may be caused either by a paint settling too quickly and unevenly due to its application over an extremely porous surface, which results from insufficient sealing by previous undercoat, or by the application of one flat coat over another. Remedy: Application by paint roller is frequently successful in avoiding this defect. Alternatively a brush applied finishing coat of a thin easy brushing consistency should be used. Brushing should be speedy to avoid dry edges forming, and the paint quickly crossed and laid off, it should be recommended that matt or eggshell finishes, especially varnish are very prone to “flash” and should not therefore be touched in any way after the initial “set” occurs – to do so will result in a permanent-“flash” in that area. To rectify the entire surface, after hardening, requires to be sanded down and recoated bearing in mind the above application recommendations.