Please be aware to keep the lid on tight when not in use to stop it hardening.
This is my favourite medium, it makes your paint stringy as if tons of lead paint is present. With experimentation it can lead to some really impressive and fascinating painterly effects. It feels to me like you have more control over the paint when using this. This is a 'putty' type medium similar to mediums used in the Renaissance.
"Velázquez Medium is an oil painting medium of finely ground calcite in bodied linseed oil. Use it to extend paint and alter its consistency, making oil colours 'long'* for finer detail and impastos. This flowing paste makes colours slightly transparent while allowing you to build impasto, thick applications of paint. When added to oil paint it does not alter the colour temperature. It can be thinned with solvent or oil. Depending upon the proportion added to paint, it does not affect the drying time significantly.
Velázquez Medium does not contain stearates, solvents, driers or natural or synthetic resins, so it is safe to add to oil paint without the worry of cracking or delaminating.
The soft white paste has little affect on colours, making them less opaque and slightly less saturated. Use it to build thick applications of paint."
Mix Velázquez Medium directly into your paint right on the palette.
Velázquez Medium is a great way to add calcite to your own paint. Add Velázquez Medium and linseed oil directly to pigment powder until a stiff paste is obtained (almost the consistency of putty). Grind the paste with a muller on a flat surface before storing in collapsible tube. Some of its properties will be temporarily lost when grinding Velázquez Medium with a muller, but should be restored when allowed to stand.