Work from large to small
Pacyra reads local colour variation, edge strength and focus weight. Large calm areas stay broad, while busy or important areas divide further until the region limit or the physical size limit stops them.
The order is the point. A shape that is wrong at stage one is wrong in every stage after it, and no amount of accurate detail rescues a mass in the wrong place. Settling the largest relationships first is what makes the later decisions cheap.
- Stage 1: large value and colour masses
- Stage 2: secondary shapes
- Stage 3 and later: controlled accents
How many masses to ask for
Two values give a notan, which answers the only question worth asking before anything is mixed: does this design hold as an arrangement of light and dark. If it does not, nothing later will fix it, and it is better to find out in ten seconds than after a day of painting.
Three to seven is the working range for a block-in you intend to paint from. Below three there is not enough information to place a brush. Above about seven the plan stops being a plan and starts being a picture of the photograph, which returns you to the problem you opened the photograph to solve.
The exception is a value study you are using to read a subject rather than to paint from, where more bands are genuinely useful. Pacyra goes to forty five for that reason. It is not the setting to export and tape to an easel.
Closed regions make transfer practical
The block-in underneath is a complete, non-overlapping partition. It covers the picture once, gives every region a stable identifier and a safe place to put its label. Painterly overlap never disturbs this layer.
That is what makes it traceable. An edge-detection filter produces lines that stop halfway and shapes that do not close, which look like a drawing on screen and fail the moment you try to fill them.
Edges describe relationships
Hard edges keep a clear contour. Soft edges stay visible but understated. Lost edges are suppressed in the painterly view while the technical boundary remains available for selection and export.
A lost edge is a decision to let two masses merge, and it is worth having marked, because it is the first thing that gets accidentally painted back in. A block-in that draws every boundary at one weight has thrown away the information saying which shapes belong together.
The guide cannot paint for you
Simplification depends on the source and the settings. It cannot promise a successful painting, replace observation, or reproduce the decisions of a particular artist.
It also inherits the photograph's mistakes. A camera compresses value in shadow and blows it out in light, and the block-in reproduces both faithfully, because it has no way of knowing which parts of the scene you would have seen differently standing in front of it. Where the photograph has gone dense and black the guide offers one mass, and the painting usually wants two. Read it as a proposal.