system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why when you wash a white load with a red item the colour runs and it goes pink, but if you wash a load of colours none of them get mixed?
gpt
Answer: They do get mixed if you wash them on hot and they aren’t color-fast (dye that won’t bleed over).

White clothes are often washed at higher temperatures and higher temperatures make the dyes from color clothing mix into the water. Mixed loads are usually washed on colder settings to prevent this/prevent colors from fading.

Newer clothing hasn’t had a chance to have that initial excess dye washed out, so most heavily dyed clothes should be washed with like colors or by themselves on the first wash.

Some clothes will bleed dye regardless. These should only be washed with like color clothes, not a mixed load.