If you have an iphone, you can use the color filters feature to set the iphone to only output red light. This is done by going into settings > Accessibility > Display & Text Size > Color Filters. You can then set the accessibility shortcut on the phone (triple click home button) to toggle this red light only mode, in Settings > Accessibility > Accessibility Shortcut. I do this whenever I am in the darkroom, and with this on, and brightness at minimum, I have never noticed issues with fogging.
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