Presented here is a list of the five stages and a brief explanation of each stage:
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Dead Color: This stage is also sometimes called "Local Color" and is the start of blocking in color to your painting in a very generalized fashion. Only mineral spirits or turpentine are used to mix with the paint at this stage to maintain a very thin or lean consistency. Mainly the artist wants to nail down the basic color of the object hitting the key notes of light medium and dark for each varying color and form.
First Painting/Direct Painting: Many artists only paint in the First Painting method. If you ignore all other steps and just do this step alone you are essentially alla prima painting. Alternatively you could end your painting after this stage and not move beyond it. Think of the whole painting as a birthday cake, "First Painting" would be the actual cake and everything else would be the frosting. The artist paints with a full range of colors, using only small amounts of medium.
Second Painting: With this method you apply paint to your canvas that has been diluted in a great deal of oil to your canvas (this is called a couch) and then you place paint unmixed with medium into that couch. This makes for a more transparent layer letting the "First Painting" show through while allowing you to still make adjustments. Mostly this stage is used for blending large areas.
Glazing: This method should always be reserved for the final stage of painting. It uses a great deal of oil and the paint that you are applying is nearly transparent. You can't really do any other method over the top of a glaze as it would cause cracking in your paint. But, you can glaze over a glaze, and keep glazing until you get the desired effect you are after. However at some point your paint might become too transparent to cause any real change.
I know many artist that only do "Direct Painting" or "First Painting", ignoring all other stages. Other artists "Dry Brush" entire paintings to give it that drawing with paint look. I even know of one artist in particular who has spent nearly 9 years working on one painting done entirely in glazes. Hopefully you will be able to take this somewhat dull information and infuse new techniques into your painting repertoire.
Side Note: I have posted a number of images of a figure painting using these stages to my website to help aid in the understanding of these principles: http://www.jphfinearts.net/Stagesofpainting.html
This article was originally published in the Corvallis Art Guild newsletter for January 2014. Here is a link to a pdf of the original newsletter:
http://corvallisartguild.files.wordpress.com/2013/05/brushstrokes_jan2014.pdf