Re: [Gimp-user] How to edit/modify part of an image (sub-area of animage)?

[Pat David <patdavid gmail com>]

Hi Rhimbo!

Did you try any of the answers to your question on the pixls.us forums?
You asked the same question there a week ago:

https://discuss.pixls.us/t/gimp-how-to-edit-modify-part-of-an-image-sub-area-of-image/2041

and we gave you some things to try (but hadn't heard back from you).  In
particular, I pointed you to a tutorial on the www.gimp.org website:
http://www.gimp.org/tutorials/Luminosity_Masks/

There is also a complementary tutorial that introduces the concepts of
layer masks if you wanted to take a look:

http://www.gimp.org/tutorials/Layer_Masks/

Those should be a decent start towards the skills and concepts you'd need
to do what you want, I think.  If you get a chance to try them out let us
know how you got along (or if you have any further questions).

pat

On Sun, Aug 21, 2016 at 6:41 PM Rick Strong <rnstrong magma ca> wrote:

> Rhimbo:  Try using a Quick Mask and a black to white Gradient to select the
> area you want to work on. Then use curves (or levels) to lighten or darken
> your selected area. You can also paint on the gradient mask to include or
> exclude things from what you will be darkening or lightening.
>
> Quick Mask is Shift+Q in multi-window mode or the little dotted rectangle
> at
> the lower left end of the scroll bars in the single-window mode. Or, Select
>  > Toggle Quick Mask.
>
> See Quick Masks and Gradients in the manual. I suggest testing first on an
> unimportant photo.
>
> Rick S.
>
> -----Original Message-----
> From: rhimbo
> Sent: Sunday, August 14, 2016 3:32 PM
> To: gimp-user-list gnome org
> Cc: notifications gimpusers com
> Subject: [Gimp-user] How to edit/modify part of an image (sub-area of
> animage)?
>
> Hello everyone,
>
> Just for context, let me say that I'm still relatively unskilled in Gimp...
>
> I would like to modify part of a photo, for example a .jpg photo. For
> instance,
> I want to adjust the exposure or lighting of some sub-area of the whole
> photo.
> How can I do that?
>
> The context of my question is as follows. Without using a neutral density
> filter, often it's very difficult (nearly impossible!) to shoot certain
> scenes
> so that all parts of the image have the optimal exposure. For example, the
> sky
> might have the right exposure but a building or foliage might be too dark.
> Or,
> depending on your choice of image area for metering measurement, the
> ground/foliage might be properly exposed but the sky over-exposed. I have
> many
> photos right now for which I'd like to lighten the dark areas without
> over-exposing the sky.
>
> I've tried playing with selecting a rectangle and changing lighting but I
> must
> be making user errors. Could someone please point me in the right
> direction....?
>
> Many thanks,
>
>
>
> --
> rhimbo (via www.gimpusers.com/forums)
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