GIMP/C2/Adjusting-Colours-Using-Layers/English-timed

Time	Narration
00:22	Welcome to Meet the GIMP. My name is Rolf Steinort and I’m recording this in Bremen, Northern Germany.
00:29	In the previous edition I got this image here, after editing.
00:33	And today, I think I should do something to set the colors
00:39	because this image is too green.
00:41	There are lot of ways to adjust the color and one of them is the Curves tool.
00:47	I click on the Curves tool in tool box and then I select the Green Channel and pull the curve down.
00:55	Now you can see that the colour channels and the fog in the image looks like the real fog.
01:02	Now, I have to adjust the curve in such a way that I get an image which is gray and not green or magenta.
01:13	I don’t want to use Curves tool because it damages the details of the image and I can’t correct the damage afterwards.
01:23	I could use the Undo tool but I will have to redo all the steps after that.
01:28	So, I want to have something that will not damage the image and I can adjust later on.
01:34	There is such a way which uses a simple filter with layers.
01:39	So, I have opened here the layer dialog.
01:43	You will see here background which is our original image.
01:47	And I simply add a new layer and I select White in Layer Fill Type and give it a name, color correction green.
01:59	Now my image is fully white but I can change the layer mode.
02:05	The 'layer mode' is an algorithm which combines the two layers i.e the original Background layer and the newly created layer.
02:16	So, I choose here the Multiply mode.
02:22	And you get the original image back, as it was before.
02:27	The Multiply mode, multiplies the pixels from the background to the pixels from the foreground and divides the result by 255.
02:37	And in a white picture, all the color channels are 255; so multiplying by 255 and dividing by 255 gives the starting point i.e. Background.
02:52	But if I reduce one channel in the new layer, it will be reduced in the background also because multiplying by say 200 and dividing by 255 gives less.
03:06	Now I want to select such a color which has a reduced green channel.
03:12	Here I have black as foreground colour which I change to background colour and white as foreground colour and you can see that red, green & blue all colour channels have same value i.e 255.
03:31	By the way, don’t be distracted by the colours on the slider here.
03:36	This is not blue, this is yellow but when I slide this down to a certain point, you see that colours in all the sliders change automatically.
03:50	Ok, I select the green slider here and pull the slider to say something around 211.
03:59	And I pull the colour which I got as my foreground colour into my image and I get the result which is way to magenta.
04:10	But I can adjust the intensity of my green reduction with the help of the opacity slider.
04:19	And when I go back to zero, I get the old image and when I pull the slider up I can reduce the green channel in the image and also avoid getting magenta into the image.
04:35	I think this looks quite good.
04:38	By using the Layers tool, I can do changes anytime I want to and also I can do fine adjustments when more layers are stacked onto it and the change will stay even if I change something in underlying picture.
04:55	There are still changes to be made in this layer as now it appears gray and I want to add a bit of blue.
05:03	Again I follow the same procedure and make a new layer and called it color correction blue.
05:11	And now I want to add a little bit of blue.
05:15	For adding blue in the image, I use the Screen Mode which is little bit more complicated than Multiply mode.
05:24	In Screen mode, the colors are first inverted and then multiplied and divided and quite complicated.
05:33	Let me change the foreground colour to black and add the colour I want to add directly and now I have to add a little bit of blue.
05:43	So, slide down the blue slider a bit.
05:47	And drag the colour into the image.
05:51	This, here, is supposed to be blue which looks still like black but it is very dark blue.
05:59	Look at the image here and when I switch this off, you see the change.
06:04	The image is definitely bluish.
06:08	I can switch off both the new layers and by that you get the starting point.
06:13	When I click on the first layer, we see the reduced channel of green and when I click on 2nd layer it adds a bit blue colour.
06:22	I think this is too much blue so I reduce the opacity.
06:27	I think this looks good.
06:30	I can adjust it later on, all the time.
06:33	The Layers tool is very powerful because you can create layer upon layers and in each layer you can change the pixels which are coming up from the lower layer.
06:44	Possibilities of doing the correction is limitless and you can do it whenever you want.
06:51	Perhaps here you can slide the opacity slider a bit down to get a good colour and you can play with these sliders which give real hand full of possibilities to change the color here.
07:05	I think I have to cover the Layers tool in detail on a special show but for today this is enough.
07:13	This is Hemant Waidande, dubbing for the Spoken Tutorial project and I hope to see you around next time.

Contributors and Content Editors

Krupali, Minal, PoojaMoolya, Sandhya.np14