It is currently 13 Jul 2020, 17:36

• Featuring Members' Works (Image Attachments) •
1: member
2: member
3: member
4: member
5: member

GIMP/GL:  🡆 Tutorials | Tips | Questions | Interests | Script Requests
Recommendations:  Index | Top 10
Resources:  Python-Fu Plug-ins | Scheme-Fu Scripts | GIMP
Python:  Lessons | Questions | Exercises
The Arts:  GIMPed | GIMPed Photos | Other | Contests | Public Domain Images | Isolated Images | Blender
Inkscape
Social:  Say Hello | Anything Goes | Shares | FCSP

Using Curves to lighten/darken image using tonal selections

GIMP Tutorials
Forum rules
Tutorials must be created by you and your own idea.
If you got idea from elsewhere and revised your own version of tutorial, please include reference and credit original authors.
For example if you found a Photoshop tutorial and wanted to write a GIMP version, you must credit the original Photoshop tutorial.
Post Reply
tim
GL Blogger

Using Curves to lighten/darken image using tonal selections

Post#1 by tim » 18 Jun 2018, 20:28


I was just randomly searching for tonal selections and this interesting technique came up.
https://luminous-landscape.com/tough-se ... elections/
After reading it, it makes so much sense with curves but I never thought of it before seeing this demonstration.
Gotta remember this technique to try out editing my photos with.
Thank you, Charles Cramer! For sharing this technique to the web.
aka Tin
:tree_02:
Tin's: Favorite Index | Simple Art === fb4yt video search | fb4yt recent video views report
Lottery numbers from image | Interested Members in TLF
Paying for hosting is to support my hobby, and donating money made from ads to The Red Cross.
         
1

Issabella
Script Tester

Post#2 by Issabella » 19 Jun 2018, 07:37


Thank you so much Tin for this interesting practical link to learn about this technique about curves. Also thanks to Charles Cramer for his amazing explanation to get surprising improvement on photos and writing his article. :gimp_clap: :happy_purple:
Issabella

Don’t be afraid to start over. It’s a new chance to rebuild what you want.
1

tim
GL Blogger

Post#3 by tim » 19 Jun 2018, 13:33


My practice using curves.



Compare by hovering mouse on/off below image.

image sources.
tonal_selection_before.jpg
tonal_selection_before.jpg (413.87 KiB) Viewed 899 times
tonal_selection_after.jpg
tonal_selection_after.jpg (454.5 KiB) Viewed 899 times
aka Tin
:tree_02:
Tin's: Favorite Index | Simple Art === fb4yt video search | fb4yt recent video views report
Lottery numbers from image | Interested Members in TLF
Paying for hosting is to support my hobby, and donating money made from ads to The Red Cross.
         
0

Pat625
Tutorial Creator

Post#4 by Pat625 » 19 Jun 2018, 15:43


Tin, how is the adjustment layer made? Are my changes made on a duplicate layer? He must be using PS with his instructions so I am not certain of how to do this in Gimp. Use duplicate or layer mask?
0

tim
GL Blogger

Post#5 by tim » 19 Jun 2018, 16:12


Yeah he's using PS.
You can make changes on duplicated layer if you wish I just edit the original.
The most import part i think is the way he uses curves to lock down tones that he doesn't want to change and change the curvve of things he wants to change.
It requires some practice i think.
What I do to know where the tones are is I make selection of say dark tone subject and use curves to tell where these tones in histogram.
Then I select the lighter tones and look at curves and observe the histogram...then once i know where these tones are generally based on histogram i can go to curves and choose my lock down points and change the others.
aka Tin
:tree_02:
Tin's: Favorite Index | Simple Art === fb4yt video search | fb4yt recent video views report
Lottery numbers from image | Interested Members in TLF
Paying for hosting is to support my hobby, and donating money made from ads to The Red Cross.
         
0

rich2005
GIMP Guru

Post#6 by rich2005 » 19 Jun 2018, 17:58


In Gimp-ese language.

Make your selection and give it a goodly feather. This one 30.

To set the break points
Bring up the color curves and set points on the color curve for a dark point and a light point. Do with ctrl + left mouse. I put in some guides (not really necesasary) to show the points I was aiming for. https://i.imgur.com/wYx09es.jpg

Now you can pull the curve around to adjust the bit in the selection between the break points. https://i.imgur.com/BllLFi9.jpg

A comparison if you can see it: https://i.imgur.com/hvu70EH.jpg

That is quick and dirty. A better way is
Duplicate Layer. Put the top layer into merge mode.
Make a layer mask from grayscale copy. Set the break points from the color layer as above, Pull the curve around on the mask.
0

tim
GL Blogger

Post#7 by tim » 20 Jun 2018, 02:59


Thanks Rich for the control to add control points...much more friendly then my method looking at histogram.
aka Tin
:tree_02:
Tin's: Favorite Index | Simple Art === fb4yt video search | fb4yt recent video views report
Lottery numbers from image | Interested Members in TLF
Paying for hosting is to support my hobby, and donating money made from ads to The Red Cross.
         
0


GIMP/GL:  🡆 Tutorials | Tips | Questions | Interests | Script Requests
Recommendations:  Index | Top 10
Resources:  Python-Fu Plug-ins | Scheme-Fu Scripts | GIMP
Python:  Lessons | Questions | Exercises
The Arts:  GIMPed | GIMPed Photos | Other | Contests | Public Domain Images | Isolated Images | Blender
Inkscape
Social:  Say Hello | Anything Goes | Shares | FCSP

Post Reply
  • Similar Topics
    Replies
    Views
    Last post

Who is online

Users browsing this forum: No registered users and 7 guests