[django62]

Hello, im django62, and i´m stuck at one point, so i hope you can help me out.
I lately discovered something by mistake, but it looked really nice.
How is it possible, to take the brightness of every pixel from the background, and transfer that to the upper layers transparency. (The upper layer is for example all blue). As I said before, I know that this works. I tried everything out and asked Google a lot of times, but I just can´t figure it out.
What I can remember doing there was just take the blue layer and transfer it to another picture. I was wondering because i didn´t do anything special.
So I hope you guys can help.

django62

[alexstandiford]

django62, on 26 March 2012 - 08:54 PM, said:

Hello, im django62, and i´m stuck at one point, so i hope you can help me out.
I lately discovered something by mistake, but it looked really nice.
How is it possible, to take the brightness of every pixel from the background, and transfer that to the upper layers transparency. (The upper layer is for example all blue). As I said before, I know that this works. I tried everything out and asked Google a lot of times, but I just can´t figure it out.
What I can remember doing there was just take the blue layer and transfer it to another picture. I was wondering because i didn´t do anything special.
So I hope you guys can help.

django62

I believe that you need to look into how layer masks work. Check out this gimp video tutorial.

[Solartide]

I have no idea what you are talking about, can you explain more in detail exactly what you are trying to do? Maybe include some pictures?

This is what I think you're trying to do, but I really have no idea. I have a blue background with Marth at 50% opacity:

This post has been edited by Solartide: 26 March 2012 - 10:40 PM

[django62]

thank you, but the video didnt work.

@solartide
unfortunetly, i dont have the image anymore. but lets take your image for instance. imagine the character-layer is the background layer, and the blue-layer, is the foreground. now what i want is to make the blue-layer transparent. but not only that. it should be in the brighter parts of the background (the parts where the light reflects more, lets say the face) more transparent than in the darker parts, (the shadows of the character) so in the end, it will look like a stencil of the character in the blue-layer.(of course every pixel has another transparency, because the brightness of every pixel on the character layer is diffrent too). i hope thats a better explenation :S

thanks for your help guys.

[ofnuts]

django62, on 29 March 2012 - 10:08 PM, said:

thank you, but the video didnt work.

@solartide
unfortunetly, i dont have the image anymore. but lets take your image for instance. imagine the character-layer is the background layer, and the blue-layer, is the foreground. now what i want is to make the blue-layer transparent. but not only that. it should be in the brighter parts of the background (the parts where the light reflects more, lets say the face) more transparent than in the darker parts, (the shadows of the character) so in the end, it will look like a stencil of the character in the blue-layer.(of course every pixel has another transparency, because the brightness of every pixel on the character layer is diffrent too). i hope thats a better explenation :S

thanks for your help guys.

"Colors/Colors to alpha" using the background blue as the color to "erase"? And then if needed, alpha to selection, and in another layer, create a layer mask an initialize it from the selection?

This post has been edited by ofnuts: 29 March 2012 - 11:28 PM

[django62]

ofnuts, on 29 March 2012 - 11:22 PM, said:

django62, on 29 March 2012 - 10:08 PM, said:

thank you, but the video didnt work.

@solartide
unfortunetly, i dont have the image anymore. but lets take your image for instance. imagine the character-layer is the background layer, and the blue-layer, is the foreground. now what i want is to make the blue-layer transparent. but not only that. it should be in the brighter parts of the background (the parts where the light reflects more, lets say the face) more transparent than in the darker parts, (the shadows of the character) so in the end, it will look like a stencil of the character in the blue-layer.(of course every pixel has another transparency, because the brightness of every pixel on the character layer is diffrent too). i hope thats a better explenation :S

thanks for your help guys.

"Colors/Colors to alpha" using the background blue as the color to "erase"? And then if needed, alpha to selection, and in another layer, create a layer mask an initialize it from the selection?

is that a question?

[ofnuts]

django62, on 31 March 2012 - 02:51 PM, said:

ofnuts, on 29 March 2012 - 11:22 PM, said:

django62, on 29 March 2012 - 10:08 PM, said:

thank you, but the video didnt work.

@solartide
unfortunetly, i dont have the image anymore. but lets take your image for instance. imagine the character-layer is the background layer, and the blue-layer, is the foreground. now what i want is to make the blue-layer transparent. but not only that. it should be in the brighter parts of the background (the parts where the light reflects more, lets say the face) more transparent than in the darker parts, (the shadows of the character) so in the end, it will look like a stencil of the character in the blue-layer.(of course every pixel has another transparency, because the brightness of every pixel on the character layer is diffrent too). i hope thats a better explenation :S

thanks for your help guys.

"Colors/Colors to alpha" using the background blue as the color to "erase"? And then if needed, alpha to selection, and in another layer, create a layer mask an initialize it from the selection?

is that a question?

A rhetorical one... not sure what you really want to do, and since you don't really look like a total noob you may already know about it. So I'm not sure my answer is the right one, hence the question mark. But of course otherwise maybe you should give my suggestion a shot.

[django62]

so here i tried to show you what i mean. i did this by hand, but i think, now you should know what i mean. the first image is the background, the second, blue one is the foreground. of course, in practical use, this would look more complex. i hope you know how to do this.

background-pic:
http://www.flickr.co...N06/7038375307/

foreground-pic:
http://www.flickr.co...N06/7038375279/

[ofnuts]

django62, on 02 April 2012 - 11:26 AM, said:

so here i tried to show you what i mean. i did this by hand, but i think, now you should know what i mean. the first image is the background, the second, blue one is the foreground. of course, in practical use, this would look more complex. i hope you know how to do this.

background-pic:
http://www.flickr.co...N06/7038375307/

foreground-pic:
http://www.flickr.co...N06/7038375279/

Easy:
- "Layer/Mask/Add layer mask", and initialize mask to grayscale copy of layer (for what you want to do, you may have to also check "invert mask")
- Click on the layer thumbnail to edit the layer (or right-click and un-check "Edit layer mask")(otherwise next step would apply to mask)
- bucket-fill layer with required color
- "Layer/Mask/Apply layer mask" if happy with result.

You would get very equivalent results using
- Colors/Color to alpha (on white)
- Check alpha-lock at top of Layers list
- Bucket-fill with required color

This post has been edited by ofnuts: 02 April 2012 - 01:13 PM

[django62]

well thank you. that worked. it was something diffrent from what i did, and it is more complicated, but the important thing is the result.
thanks