I am talking about scenes where lets say a woman loses her father and they show scenes of them at the beach when she was a child and her father was chasing her.
These kind of scenes look blurrier, greyish. I can’t describe.
And I can’t find a clip of what I mean. Maybe someone has a clip to something simular with that filter?
There’s no one, specific way to do it, and in Hollywood films it’s usually not a plug-and-play filter like you’re thinking. Usually it’s some combination of lighting, color grading, post-processing, and even retiming.
With lighting, they might light the scene more softly and evenly, reducing overall contrast. This can be simulated in post, but it’s often more effective to do it in-camera. In more stylistic flashbacks, they may even include bright backlighting to further drive home the feeling of memories that focus on specific moments.
In the realm of color grading, sometimes just some slight desaturation, which would give the grayish look you’re talking about, is enough. Sometimes they go with that plus turning down the blue to give it a “warm” look, and sometimes they’ll go all the way and make it look sepia or black-and-white.
With post-processing, they might indeed reduce the sharpness by applying a blur, or they might just apply a slight vignette (which darkens the image slightly at the edges).
With retiming, they might slow down the film from the memory ever so slightly; by 15-25% or so. Not enough to make it distracting, but just enough to lend it an ethereal air.
Most of the time, they’ll do one or two of these; they wouldn’t do all of them unless they were trying to make a joke. Also, don’t rule out the powerful effect of sound design in scenes like this; with a few slight visual cues and a few subtle sound elements, it can completely change the vibe of the scene.