Temperature and tint solve different casts
Temperature is the blue-to-amber direction; tint is the green-to-magenta direction. Warm indoor lamps often make a white card look yellow. Blue sky light can make shaded neutral surfaces look cool. The three panels above use one photo with illustrative cool and warm treatments to make this direction visible.
Find something that should be neutral
A white shirt, gray card, or unpainted paper can help, but only if it is actually neutral and shares the subject's light. Compare several neutral areas; a colored wall can reflect onto one side. Avoid forcing every shadow to pure gray because real light can have different colors.
Tint is a separate green-to-magenta direction.
Protect skin and intentional mood
Faces are useful checks, not perfect gray references. A correction that makes a wall neutral may turn skin green or remove the warmth of sunset. Adjust in small steps, then compare before and after at normal viewing size.
What Pixlena offers today
Pixlena currently provides resizing, compression, conversion, and image preparation, but not a white-balance slider. Use this lesson to judge a source image before export; changing JPEG to PNG cannot remove a color cast already baked into the pixels.