Have hundreds of old slides to scan in, and unfortunately, the majority of them seem to be Kodak Ektachrome, and have a red/brown tinge to them.
Is there a good tutorial around, or an "easy fix" to correct this? (He says, hopefully...)
Sample: [
attachment=7396]
This is how I might apply a correction.
White balance the image, Depends on the image.
Colors -> Auto -> White Balance might give a satisfactory result or manually ,
Colors -> Levels and pick white and black points from the image.
Duplicate that and set the layer mode to Screen. Now colorize that layer, I use the GEGL filter
Tools -> GEGL Operation -> Color Overlay Pick Green and adjust (to very dark green). Keep an eye on the subjects in the image. This is just a variation on a well-known procedure for underwater photos.
If more is needed, then
Layer -> New from Visible and work on that
Depends on the image, if the background is a bit bright, Using Ofnuts luminosity plugin from
http://sourceforge.net/projects/gimp-too...s/scripts/ ofn-luminosity-masks.zip dated 2019-12-01
It makes a selection. Background adjusted for brightness, selection inverted and contrast adjusted,
[
attachment=7397]
Duration 2 and a half minutes
https://youtu.be/YGltUgHejco
Otherwise, the Green channel is mostly gone, so another options is to convert to B&W using
Colors ➤ Desaturate ➤ Mono mixer, set the Green to 0, and use a bit of the red (0.2) and a lot of blue (.9) (adding blue adds contrast), and then increase contrast:
Thanks for the tips!
Will have a play.