Thank you ^^
I've never red Naruto, sorry...
And why red ? I had a blue too, but and I can't remember where I put it. Anyway, its color was darker than the red one and I had some grey shadows after aplying the filter, so maybe that's why artists use the red.
In Toshop you have trhee type of filters : Red, Blue or Green. You can't do it with an other color.