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Background colour problem.

Feb 16, 2014, 23:43
Post: #1
Background colour problem.
Hello.

Thanks in advance for any help you can offer.

I did a search on your forums and couldn't quite find an answer.

I'm simply trying to save my file. The file is being used for a stencil I'm working on. So it's set to only 2 colours. I have the background on alpha channel. Here's where my problem comes in. I have the background set on white, but when I export it and open up the file the background shows up as a light grey. I've tried everything I can possibly think of to change the background to white. When I try to add another layer and change that layer's colour to white, it shows up as light grey. I just don't get it.

Please help.
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Feb 17, 2014, 00:01
Post: #2
RE: Background colour problem.
All of a sudden it worked. I can't believe it. lol

Sorry, can you please delete this thread.
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Feb 17, 2014, 03:59
Post: #3
RE: Background colour problem.
(Feb 16, 2014 23:43)phono45 Wrote:  The file is being used for a stencil I'm working on. So it's set to only 2 colours. I have the background on alpha channel. Here's where my problem comes in. I have the background set on white, but when I export it and open up the file the background shows up as a light grey. I've tried everything I can possibly think of to change the background to white. When I try to add another layer and change that layer's colour to white, it shows up as light grey. I just don't get it.

Please help.

The way your trying to turn the background to white maybe incorrect, as you only need the alpha channel for transparency (for saving you usually won't need to turn off / on alpha channel) so this problem may come back.
The white is a new layer set to "white" in the layers window:

-put your layers on top of the new "type: white" layer
- Select the bottom layer "white" layer and make sure it covers the whole canvas using the move, scale or bucket fill tool (Move, Scale ,Bucketfill) there should be no grey checkerboard visible before you flatten it VVVVVV
- then right-click on a layer "Flatten" or Layer > flatten image,
then export as a PNG(Quality prints, local viewing), JPEG(for fast loading on websites), GIF or other(see below)

(Feb 17, 2014 00:01)phono45 Wrote:  All of a sudden it worked. I can't believe it. lol

Sorry, can you please delete this thread.

So I'm not sure you wan't to be so quick to dismiss your issue. If it does come back, post up a screenshot with:
- full layers window visible (layer modes & layers...) & canvas
- Output image (with grey background) (how the image looks after you export it & re-open it)

"In order to succeed, your desire for success should be greater than fear of failure." BC
[Image: 29uocaf.png]
iFS007 tut vids on YT ~ auto color B&W landscape tut
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Feb 23, 2014, 23:43
Post: #4
RE: Background colour problem.
Thank you.

But, why do I want to flatten the layers?
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Feb 23, 2014, 23:55
Post: #5
RE: Background colour problem.
Ya you're right about me dismissing the issue too early. I did as you said and added another layer set to type - white. I can tell there is a problem right away because when that new layer opens up and I just put the eye on that layer to look at it the layer that is supposed to be "type white" is showing up as light grey. I don't know why this has to be so difficult.

Any ideas? lol
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Feb 24, 2014, 07:16
Post: #6
RE: Background colour problem.
Can you post a screenshot showing your image and the Layers list?

Now answering your questions on
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Feb 24, 2014, 09:16
Post: #7
RE: Background colour problem.
(Feb 23, 2014 23:55)phono45 Wrote:  ... because when that new layer opens up and I just put the eye on that layer to look at it the layer that is supposed to be "type white" is showing up as light grey. I don't know why this has to be so difficult.

Any ideas? lol
(Feb 24, 2014 07:16)ofnuts Wrote:  Can you post a screenshot showing your image and the Layers list?

Not 100% sure yet, along with the screenshot of your layers list & image in Gimp,
What is your OS?
Version of Gimp? gimp #.#.#
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Feb 24, 2014, 21:30
Post: #8
RE: Background colour problem.
I am using Gimp 2.8 for Mac.

I attached a screenshot. I hope it helps. You'll see I added the layer like you told me to. I put it on "type white" and it still shows up as light grey. And I have the top layer and the supposed white layer open and my first layer doesn't even show up when I put that layer behind it.

Really weird. Dodgy


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Feb 24, 2014, 22:04
Post: #9
RE: Background colour problem.
You are working in "indexed color" mode (see the title bar) and there is no white in your color map. Convert your image to full RGB (Image>Mode>RGB). Convert to indexed mode (if really necessary) only when exporting (and keep a full RGB version for further editing).

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Feb 24, 2014, 22:45
Post: #10
RE: Background colour problem.
I need my image to be in indexed colour because I make multilayered stencils. I change the image to greyscale then drop it down to 4 colours and separate them to be printed and cut.

Would adding white to my colour map do the trick? If so, how might I go about that?

Thanks for all the help!
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Feb 24, 2014, 23:31 (This post was last modified: Feb 24, 2014 23:32 by ofnuts.)
Post: #11
RE: Background colour problem.
Yes, adding white to the colour map will do the trick. See Windows>Dockable dialogs>Colormap.

But you can also do the color separation at the end.

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Feb 25, 2014, 02:43
Post: #12
RE: Background colour problem.
Ok great. I just did a test and it saved as white. You did it !! Thank you!.

But just a couple more questions if you don't mind.

The first one being. Why do I have to manually add the white to the colourmap?

And two. I will attach a screen shot for this one. When I add a new layer - type white, why when I put the eye on say 1 or all of the layer, do my dark layers not come through and show up through the white one ??

Thanks again.


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Feb 25, 2014, 08:34
Post: #13
RE: Background colour problem.
(Feb 25, 2014 02:43)phono45 Wrote:  Ok great. I just did a test and it saved as white. You did it !! Thank you!.

But just a couple more questions if you don't mind.

The first one being. Why do I have to manually add the white to the colourmap?

And two. I will attach a screen shot for this one. When I add a new layer - type white, why when I put the eye on say 1 or all of the layer, do my dark layers not come through and show up through the white one ??

Thanks again.

1) because colors in a color map are a scarce resource. If you let Gimp add colors implicitly it gets exhausted very quickly. Try this: and a white layer create a circle selection and fill it with black. The use Colors>Info>Color cube analysis. 66 colours, due to anti-aliasing. So, if you use a colormap, you manage the color map. If you want the colormap to be generated automatically, then work in RGB mode, and convert to indexed at the end. Then the colormap will be optimized for the colors you have.

2) because the top layer is at 100% opacity.

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