Paper that holds the line

A house portrait is only as permanent as the sheet under it, and the choice of paper happens before the first line is drawn, because the paper decides what the pen can do. Three properties carry the decision: weight, surface and sizing. Get them right and the sheet outlives the frame; get them wrong and the drawing is a letter that yellows in a drawer.

Weight is the floor

Paper weight is measured in pounds or grams per square meter, and for a portrait it is not a luxury figure, it is structural. Light stock, the 20-pound bond of office printers, buckles the day a wash touches it and cockles under a mat within a year. Working drawing paper for inked portraits starts around 100-pound cover weight, roughly 270 grams, and a washed sheet wants more, the 140-pound watercolor stock that can take a wet brush and dry flat.

The weight also sets how the sheet feels in the hand, and that matters more than it sounds. A portrait is handed around at closings and Christmases; a sheet with body reads as an object made to last, which is precisely what it is.

Surface is the line

The surface decides what the nib sees. A hot-pressed or plate finish is nearly smooth: the pen glides, the line stays sharp and thin, and hatching resolves into fine texture. It is the surface of choice for small detailed portraits where the window muntins are two millimeters apart. A cold-pressed or "not" finish has tooth: the line drags slightly, edges soften, and the paper's grain becomes part of the drawing. It suits bigger sheets and livelier hands, and it loves a wash because the tooth breaks color into granulation.

Sizing is the shield

Sizing is the least visible property and the one that decides whether the ink bleeds. Sized paper has gelatin or a modern substitute worked into it so liquid sits on the surface instead of soaking in. An ink line on well-sized paper stays exactly where the nib left it; on unsized paper it feathers into the fibers and every stroke arrives a half-weight heavier than intended. The wash depends on sizing even more: watercolor on an unsized sheet sinks instantly and dries dead, with none of the luminosity the medium is for.

The acid test

Permanence closes the choice. Wood-pulp paper carries the acid that browns newsprint; rag or acid-free stock does not. A house portrait is bought to hang for fifty years, so the sheet is always acid-free, buffered where possible, and the board it ships on and the mat it goes into must be as well, because the acid migrates.

The three finishes side by side

Laid next to each other, the stocks announce their trades. Plate finish gives the sharpest line and the least forgiveness: every hesitation shows, so it flatters a confident hand and a detailed subject. Cold-press gives a line with grain in it and a wash with life in it, the forgiving middle ground most portraits are actually drawn on. Rough finish is the specialist: beautiful for big foliage and weathered stone, wrong for a sheet whose windows are three millimeters across. The artist chooses once, for the subject and for the wash it will or will not take, and the client sees the consequence framed, which is why the choice is worth one conversation.

The sheet, filed

The paper is chosen once and it answers for the drawing forever: hold the line, take the wash, stay white, stay flat. The next sheet follows the portrait past the drawer into its first housing, the mat and the frame it will spend its life behind.