GIMP
Home > CentOS > CentOS 6.x > Image processing tools > GIMP
There are newer notes on this at Rocky 8.x GIMP
GIMP or (GNU Image Manipulation Program) is a very powerful image editor which supports layers. GIMP may require considerable learning for a beginner but some features such as 'Script-fu' which can be used for writing text with good patterns such as 'Fire', 'Water', 'Ice' etc. is very easy and intuitive to use. Users who have used advanced image manipulation tools similar to commercially available photoshop should find Gimp to be very useful open source and free alternative for image manipulation.
Darken existing image using GIMP
If there is image of a document which is appearing very light due to bad printout, erased / fadded over time, etc. Then such images can be darkened using GIMP as follows:
- In layers duplicate existing layer.
- Renamed the copied layer to "Contrast Mask"
- In contrast mask layer use Image -> Colors -> Desaturate
- In contrast mask use Image -> Colors -> Invert
- In layers choose mode as 'Overlay'. Keep both layers visible.
- Then change 'Brightness and Contrast' setting for "Contrast Mask" till image looks similar to desired output.
- Choose Layers -> Flatten image
- Save output image and use as required
Refer https://www.gimp.org/tutorials/ContrastMask/
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