Improving picture quality
While researching your family tree, you will come along old sources that need carefull handling. Pictures from these taking in an archive are often not optimal, and need cleaning up to make the text readable. Some pictures are snapshots of microfilm screenreaders.
Here we show how you can work on your picture to make the text come out better, improving readability. All with open source software, off course!
The sample picture 1
The sample picture is a raw jpeg picture of 1.5Mb. Light is centered in the middle, getting darker at the edges.
A good application to view these files is Gwenview (KDE).
To edit it, The Gimp] comes to the rescue.
- Open the file.
- Select the relevant portion with the
rectangular select tool. Copy and paste into a new canvas: type respectively, CTRL+C, CTRL+N + click OK, CTRL+V
- Save the file in the GIMP xcf format
In Gimp, the Filters menu has the correctly named 'Enhance' submenu.
2x2 Contrast Enhance
- Select the
Destripeoption, and set the value to 50.
- Now, in the Tools menu, go to the Colour Tools submenu, and choose Curves. You can now play with the curve level to get a better contrast on the picture
- As a last edit, select the centre highlighted region of the picture with the elliptic selection tool, and select in Tools menu--> Colour Tools the Brightness-contrast option, and reduce the brightness.
Now, save the result as png with maximum compression level.The result: