Everything you need to know about oils for oil painting
Bleached linseed oil differs from purified linseed oil only in terms of colour. As the colour of linseed oil is affected by conditions (light, oxidation), the difference in colour between the two oils will largely disappear over time.
It is a very oily oil and therefore particularly suitable for application in final coats. Link to Oils for oil paint
Boiled linseed oil is a linseed oil heated with siccatives that can be used in a homemade oil paint medium to make the paint dry faster.
Compared to linseed oil, poppy oil dries slower, is paler, yellows less and is less likely to scorch the paint. Because of these properties, a homemade medium based on poppy oil can be used in combination with light colours in the "alla prima" technique. However, poppy oil forms a weaker film than linseed oil and, when used in the lower layers, can cause problems for the adhesion of linseed oil paint in subsequent paint layers. It is therefore recommended to use poppy oil only in the last layer when layered painting. Link to Oils