I have gotten a couple of questions about priming with the flake white. Since there are several varieties of white paint which contain the lead carbonite pigment, I thought it might be helpful to just give this quick primer about paint pigments.
And hey, I am no expert, but I do know where to look for help.
First of all, companies that make our oil paints can call a color anything they want. So "medium red" from company A might not look anything like "medium red" from company B. You will have to learn by trial and error which brands of paint for which colors you prefer. For example, I like Windsor Newton's Cadmium Yellow Light better than Rembrandt's Cadmium Yellow Light, but I do like Rembrandt's Transparent Oxide Red.
There is however, a way to compare what colors MIGHT look like before you buy them and take them home.
For each of the chemical compounds that comprise the many different color paints we use, there is a chemical ID. This ID is consistent in the industry, so you can look at a tube of paint and know what's in it. It's the "recipe" for that particular tube color.
For example, let's say you usually use Windsor Newton's "Windsor Green". It's a nice dark cool green and you like it. But the store is out of Windsor Green and you have to get something TODAY! How do you find something that is similar? Look at the old tube of Windsor Green, and you will see that the pigment ID on it is PG7. It is a Phthalocyanine green made actually from polychlorinated copper phthalocyanine. (doesn't this make me sound smart?)
So, just go looking through the other brands of green until you find one with that same chemical name. For example, Blockx Green, made by Blockx, is also PG7. You could safely assume that it will behave similarly to the Windsor Green. Be sure and check for other ingredients as well, as some will be mixes of other compounds, as well as fillers.. try to find an ingredient list that matches the color you've been using.
There are several other factors that are identified on your paint tube.
The "permanence rating" which goes from I to IV, (I think - I"m writing this from memory)
will tell you how light fast a particular pigment is. Alizarin Crimson is notably bad in this regard, turning almost black eventually (thought maybe not in our lifetime ) and if you look at a tube marked Permanent Alizarin, you will see it is a different chemical compound, usually some form of a quinacridone red.
Also, if the name of the color includes the word "hue" then it is usually student grade, and it is NOT the actual chemical that comprises that color. For example, Cadmium Yellow HUE is NOT cadmium yellow. It LOOKS like cad yellow when you put it on your palette, but it will NOT behave like cad yellow when you use it. HUEs are cheaper, and if you're serious about your art, I'd avoid them if at all possible. It's like buying the cheap potato chips at the store. Just not the same at all.
If you are really interested in all this stuff, and it IS fascinating to get an overview of what our paints are comprised of, then you can look at this chart. Not all brands or names are listed but it has a vast array of them.
There's way more information, and it is helpful to some extent to know how some pigments are likely to behave, or which are more or less transparent,, etc.
Or, you can just GO PAINT......