Gimp-Forum.net
Colour Double Exposure - Printable Version

+- Gimp-Forum.net (https://www.gimp-forum.net)
+-- Forum: GIMP (https://www.gimp-forum.net/Forum-GIMP)
+--- Forum: General questions (https://www.gimp-forum.net/Forum-General-questions)
+--- Thread: Colour Double Exposure (/Thread-Colour-Double-Exposure)

Colour Double Exposure - Espermaschine - 11-04-2017

Anybody has an idea how to make this double exposure effect that uses (RGB) channels ?

Like here:
http://designingflicks.com/exposure-coloring.html#gal_post_6241_exposure-coloring-2.jpg

or here:
http://designingflicks.com/exposure-coloring.html#gal_post_6241_exposure-coloring-5.jpg

In the original Photoshop tutorial its done by turning off one or more of the RGB channels, but this isnt possible in Gimp for individual layers
(video: youtube.com/watch?v=FC7ldDACArM).


I tried turning off one or two channels in Gimp and then doing a 'New From Visible', using that newly created layer with a Screen Blendmode, but i was wondering if there is a better way.
The Channel Mixer perhaps ?

RE: Colour Double Exposure - Ofnuts - 11-05-2017

You can also make groups with, from bottom to top:
  • A copy of the original image
  • A layer filled with some color (R,G,B, (or C,M,Y) and set it to multiply
You can then set the group's blend mode (add, Darken only...) and opacity, and of course move the group

RE: Colour Double Exposure - rich2005 - 11-05-2017

Fiddled around without much success.

1. The examples are carefully chosen, dark hair is going to work best

2. The bit I cannot get without a lot of manual editing. The skin tones are retained. Easy enough to change the colour of the whole layer.

RE: Colour Double Exposure - Espermaschine - 11-05-2017

(11-05-2017, 10:10 AM)Ofnuts Wrote: You can also make groups with, from bottom to top

Wasnt there a bug that prevented using blendmodes within groups or something ? It seems to work now.

I guess there are many ways on how to colorize an image, but is this the same as mixing channels ?
I was thinking that decompositing an image would give me a red, blue and green layer, but instead i get three monochromatic images.
Why is that ?

(11-05-2017, 12:32 PM)rich2005 Wrote: 1. The examples are carefully chosen, dark hair is going to work best

This is my impression as well. "Lenna" for example doesnt produce very good results.

RE: Colour Double Exposure - Ofnuts - 11-05-2017

(11-05-2017, 09:27 PM)Espermaschine Wrote:
(11-05-2017, 10:10 AM)Ofnuts Wrote: You can also make groups with, from bottom to top
Wasnt there a bug that prevented using blendmodes within groups or something ? It seems to work now.

I guess there are many ways on how to colorize an image, but is this the same as mixing channels ?
Yes, a long at the coeffs in the mixer are positive values. The mixer also gives you the ability to keep the luminosity, but this method allows you to tweak the coeffs later by adjusting the color layer opacity.

(11-05-2017, 09:27 PM)Espermaschine Wrote: I was thinking that decompositing an image would give me a red, blue and green layer, but instead i get three monochromatic images.
Why is that ?

Because the channels are greyscale... More generally, Color>Components>Decompose can generate several decompositions, and in most decompositions a color wouldn't make sense, and even when they do (RGB decomposition) things could get complicated: what should happen on recomposition if you add green in the red channel layer?

RE: Colour Double Exposure - Espermaschine - 11-06-2017

I was able to make this, and i guess ofnut's idea about colorizing the image really works best.
Its a lot more intuitive and flexible than playing around with the channelmixer, for sure.

[attachment=914]

RE: Colour Double Exposure - rich2005 - 11-06-2017

Much better than the pair of beauties I got. Normally these are on my ramdisk and vanish at the end of the day, but still have this. Should I try and improve this?

https://i.imgur.com/ygZ38Qv.jpg

Maybe not Wink

edit: forgot to mention. The masks come from Saul Goodes luminosity mask script.

RE: Colour Double Exposure - Ofnuts - 11-06-2017

(11-06-2017, 08:54 AM)rich2005 Wrote: Much better than the pair of beauties I got. Normally these are on my ramdisk and vanish at the end of the day, but still have this. Should I try and improve this?

https://i.imgur.com/ygZ38Qv.jpg

Trump's hair looks even more fake than usual!

RE: Colour Double Exposure - Espermaschine - 06-20-2018

I had another look at this effect, and dug out this YT tutorial that i had found earlier.
https://www.youtube.com/watch?v=x3xFAbX5R84

Its not very well made...so the steps are:
  • copy layer
  • paste layer (floating layer appears)
  • deselect a channel (so in case of the red chnnel: three channels are highlighted blue, the red channel is not)
  • offset floating layer with the Move Tool -> anaglyphic effect appears
  • anchor floating layer

Now here is my question: why does this work the way it does ?

For example, if i convert the floating layer into a normal layer, the effect is gone.
Why ?