>>2255895I'm working from a photograph right now. Depending on the idea I work also from imagination together with photographs or only imagination. I dislike to paint from observation when it comes to human figures, it always make me feel awkward for having so much of the time of that person, uncomfortable and worried if the model is too bored or whatever else. It draws my attention way too much from the work.
>>2256576Depends. It is basically depositing the general areas of flat color, instead of working each area until the end separately. The advantages is that you have the idea of color and feel of your work and you can see the "whole picture" instead of getting lost into separate areas that in the end may not be nicely tied together. If you are painting wet-on-wet (alla prima, when you plan to finish in one sitting) that process is usually made with normal thickness paint, and after you are done with blocking your work with the blocks of flat color you deposited, you start softening the edges and working into the additional details. If you are working with layers, you make a thinner layer of paint to work with fatter layers after. To do the opposite can cause your painting to start cracking. I personally block-in using a lot of paint thinner as a medium, extremely thin layer, and then proceed to use turpentine + linseed oil. But you can makethe blocking in a bit fatter than I do. Here is some video of some alla prima process, he is blocking the colors, check the process at least until 1:30min, that's blocking-in.
https://www.youtube.com/watch?v=tskblblgElU 
