Chromatic gilding varnishes are found in a number of historical objects, paintings, sculptures, products of artistic handicraft. Scrumbling on metal foil was applied in order to obtain the effect of glittering, evidencing the high value of the applied material. On white, silver or tin foils, golden-blue varnishes are often put to replace gilding as well as red, green or blue varnishes imitating jewels or glazy gowns. The reconstruction of blue gilding varnishes is a difficult conservation problem as they are in most cases poorly preserved, they have lost their scrumbling properties and their tint undergoes changes. Prussian blue is among the most often used blue dyes. The dyes applied to gilding varnishes during restoration shoould have a tint similar to those used previously, a good resistance to environmental agents and light, and should be easily dissolved in varnishes. Among the synthetic dyes, the aliphatic ones give good results in the industry, and experiments have been carried out to verify if they fulfil the above requirements. Results are given and discussed. They evidence a good resistance of aliphatic Follblau 143040y, Leuchtenblau and Blau dyes (Talens and Rowney) to light destructive agents and damaging substances. These dyes can be applied in foils in synthetic varnishes, e.g., Rembrandt (Talens or Rowney) as well as in mastic varnish. Aliphatic dyes can not be applied in oil resin varnishes as they are hard to spread over the foil surface and slow down the drying of oil.