Daylight changes with weather, place and time. Its name alone does not guarantee a fair comparison. What matters at home is seeing two fabrics under similar conditions and then checking the result in everyday settings.
Understand the daylight reference
CIE standard illuminant D65 represents average daylight at approximately 6500 kelvin for defined colour measurement. Your window does not constantly reproduce it. No measuring station is needed for a wardrobe comparison; wait for steadier light if sun and clouds keep changing.
Choose the actual window conditions
Position the mirror so both sides of your face remain visible without harsh sunlight. Move back if needed. A north-facing window can be useful but is not mandatory; nearby buildings, trees and coloured surfaces also affect the light.
Reduce mixed influences
Turn off ceiling, mirror and table lights initially. A relatively unobtrusive background helps; moving the mirror may suffice. A phone camera can change exposure and white balance between shots, so inspect real fabrics first. Use photos as reminders with brief notes about place and time.
Choose a workable time
No clock time suits every season and room. If evening light is poor, prepare pairs and compare later. For paid advice, ask how lighting is controlled. A stated kelvin value does not describe every property of a lamp or establish uniquely correct lighting.
Check ordinary environments
Review office jackets, outdoor coats and evening clothes in comparable conditions to their use. Two navy fabrics may match at the window and separate under another lamp. Seek combinations whose variations you enjoy, rather than a supposedly permanent scientific seasonal identity.
Frequently asked questions
Is cloudy weather always better?
Even cloud can give soft light, but brightness, surroundings and viewing direction still matter. Check whether fabrics and face are comfortably visible.
Can I compare outside?
Yes, in steady light without strong reflected colour. Direct sun, moving shade or dense green foliage may complicate the comparison; a sheltered bright spot can be easier.
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