A window is a large source whose effect changes with position. Beside it, one side of a face may be bright and the other noticeably darker. Farther into the room, illumination is distributed differently and usually becomes weaker. For a portrait, the first requirement is therefore not extra lamps but finding where light, shadow and background work together.
Read the window and its surroundings
First check whether direct sun enters the window or mainly diffuse skylight. Direct sunlight can create hard bright patches, while an overcast sky often gives softer transitions. A thin pale curtain can diffuse direct light but reduces brightness. Judge the effect on the face rather than simply how bright the window looks.
Turn off distracting room lamps if they cast a different colour onto skin. A warm lamp in the background may remain visible as long as it does not unintentionally mix with window light on the face. A strongly coloured wall can also tint the shadow side. A neutral background is not compulsory, but controllable mixed light helps.
Turn the person gradually
Start with the person beside the window and ask them to turn their head slightly towards it. Watch shadows move across nose and cheek and notice when both eyes become readable. Small changes often suffice. A fixed angle is less useful than the actual face shape and window height.
If eye sockets remain dark, the source may be relatively high or the face turned too far away. Adjust head direction or position before brightening the entire exposure. Otherwise already bright forehead and cheek areas become too light while the unhelpful shadow shape remains.
Fill the shadow side
A white card opposite the window can bounce light back. Bring it closer for more fill and move it away for stronger contrast. Make sure it actually receives window light. A surface standing in shadow has little light to return regardless of its size.
Compare a frame without the reflector and one with it. Shadows do not need to disappear; some detail in an eye or dark hair may be enough. A silver reflector can be stronger and more directional but harder to use unobtrusively. A matte white surface is easier to control at first and produces less conspicuous bright reflection.
Two arrangements for different results
For an even portrait, the person can face almost toward the window while you photograph from beside it. Turn them enough toward you for a natural gaze and inspect the nose shadow. If it crosses the mouth awkwardly, first change facial angle or height. A bright reflector does not always solve an unsuitable shadow shape; initially it merely makes it lighter.
For stronger modelling, place the person more sideways to the window. This creates a clearer bright and dark side of the face. Begin with a white surface well away on the shadow side and move it closer until enough detail appears. Compare a frame without and with that fill. If both sides become almost equally bright, the desired sense of volume may disappear.
Then move the person a step farther from the window without changing their rotation. Inspect brightness and background together. A distracting window edge may move away from the head, or the wall may form a calmer relationship with the face. Readjust exposure after moving; unchanged settings do not fairly compare different positions.
When photographing several people in succession, mark a starting position but adapt it individually. Height, glasses and gaze change reflections and shadows. A repeatable basic setup saves time but does not replace a brief check of the actual face.
Check exposure and focus together
Choose an aperture that supplies enough depth of field for the head position. With a turned face, a very wide aperture may render only one eye clearly. Check shutter speed as well because a seated person still moves slightly. Raise ISO when necessary rather than automatically accepting a very long exposure for a quiet portrait.
Expose for the important skin area and check bright patches. A very bright window within the frame can influence automatic metering. If it is not part of the story, a slight reframing simplifies capture. Use eye autofocus if it reliably selects the intended eye, and magnify a test frame. A bright catchlight does not replace a genuinely sharp iris.
A short coherent sequence
Once light and position work, avoid continually changing every setting. Make a quiet head portrait first, then a wider view including hands, and finally one with more surroundings. Keep the lighting direction recognizable. This creates a small sequence with different information but consistent colour and shadow. Pause to check when a cloud substantially changes brightness or the person changes position.
