[scribus] Lighten dark colors

[JLuc]

Hello

My new printer didnt provide an ICC profile file when asked (said it's not required afaicr).

Printed photos are not too bad but are quite often too contrasted
and dark areas appear flattened and shifted to the very dark.
Sometimes also the light areas appear also flattened and shifted to the very light
but most issues are with darker areas.

I've asked some advices to the printer but i'm afraid i wont get usefull answer.
(Do you sometime get any usefull answers from your printers ?)

As for now i'm thinking of bash-editing all images so as to curve the dark colors lighter.
How could i best bash achieve this on linux ?
What should i care do to avoid worsening the print ?

JLuc