Size, framing and the three numbers nobody checks

Most guidance about professional portraits is about expression, wardrobe and confidence. The things that actually decide whether an image works are three numbers, and they are boring.

Number one: the display size

Not the file size. The size it is actually seen at. In a feed or a search result, forty-eight pixels. On a conference badge, about fifteen millimetres. On a business card, less.

At those sizes skin texture, eyebrows and fine gradients are gone. What survives is the outline of the head and two or three masses of light and dark. What size actually means here goes through the specifications, and the useful takeaway is that you should be selecting at the display size, not at full screen.

Number two: the crop ratio

Everything below the collarbone is wasted area. A perfectly good photograph becomes unusable purely through framing, and this is the single most common fixable problem — no reshoot required, five minutes of cropping.

Number three: the contrast between hair and background

The one that is invisible until it matters. Dark hair against a dark wall gives a silhouette with no face in it once scaled down. The fix is not white; it is separation from *your* hair colour, which is a different colour for different people.

The rest of it

The general treatment covers the conventions, and it is worth reading against the three numbers above rather than instead of them. Advice about smiling and posture is real but second order; the geometry decides first.

If you want to go deeper by subject

The material splits into a few genuinely different problems and it is worth going to the right one. The full index lists them; the tools section is about choosing software, the photography section is about how the images are made, and the industry section covers the profession-specific conventions, which genuinely contradict each other — medicine wants warmth, law wants restraint, and the same photograph cannot do both.

The test

Scale your image to forty-eight pixels and set it beside the original. If you cannot tell where your head ends, that is the version most people see, and no amount of resolution changes it.

One minute, and it is the only test that reproduces the real viewing conditions.