GIMP :: Using Selection Deleting To Transparency Via Alpha Channel
Dec 12, 2012
I have removed the background from a photo using selection deleting to transparency via alpha channel. My dog was left. I then exported to png. When I try to upload the dog to use in a label, (Open Office), the back ground turns to white.
I already have an image file in png format..which I want to use as an application launcher icon for my android application.
The android specifies image with following properties for the launcher icon(Will need 4 different image to support different screen size in mobile devices)
Launcher icons should be 32-bit PNGs with an alpha channel for transparency. The finished launcher icon dimensions corresponding to a given generalized
Screen density are shown in the table below. 1. 36 * 36 px 2. 48 * 48 px 3. 72 * 72 px 4. 96 * 96 px
I would like to create 4 png files(with specifications mentioned above) from the already existing image file. How do I do that in GIMP.
I am completely novice to image editing(Never touched any image editing software before) and not sure how to achieve this in GIMP.
I made a complicated selection, which I saved to a channel. Then I inverted the selection and tried to delete the inverse (hopefully to transparency, but deleting to a background color would be better than not deleting at all). However, nothing happens when I press the delete key, or when I select "Clear" from the edit menu. Trying to use the Cut command doesn't work, either.
After deselecting, I can get the selection back through the channels dock, by right-clicking and then choosing "Channel to selection" or "Add to selection." It appear to replace the selection from the channel properly. I just can't delete anything.
For quite some time I've been trying to find the best way to remove a white background from images. I've checked out the sticky thread on this forum and as my image isn't of great quality and because it features quite a lot of white that won't apply.
Recently I found this tutorial which is supposed to work great (as seen in the comments). However, I think that because of a GIMP update that won't apply anymore somehow. I was hoping you guys might know what was causing it.
Everything works well until I get to step 7, where I have to select to Alpha. There it selects just the outlines, but my selection includes inner parts of the image, not just the background. And then after I invert and delete, the white that remains still has transparent parts that show up on the upper layer. So, am I doing something wrong with the Alpha to Selection, is that tutorial updated or is there a better way to remove the background from ie. a logo with just one background colour which isn't of great quality.
I'm developing a tile based game, I have basic ground tiles, and above these tiles can be objects. My game engine supports objects with an alpha channel, where the alpha channel is used for transparency:
alphachannel 0 = completely invisible pixel alphachannel 255 = opaque pixel alphachannel between 0 and 255 means the object and the background tile below that are blended, like semi-transparency.
This is useful to give the objects soft edges, and for semi-transparant fire, ghosts, and other nice looking effects. Code:
I'm trying to do something that I could previously do with other image software. I want to 'paint' the transparency of a layer using the alpha channel. So when I paint black on the alpha channel it makes that part of the layer completely transparent, and white makes it completely opaque (and grey shades are in between). From what I understood of the help, this should be possible by just creating an alpha channel and painting in it. But when I try and then click back to display the RGB channel to look at the changes I've made, nothing actually changes. Whatever I seem to do to the alpha channel it doesn't actually affect the layer's transpancy at all.
I am trying to select the aplha channel (and make it a selcetion ) by using the command +mouse click but I only get the black selected not the white. So i have to invert selection, which is annoying. Am i missing something? this worked 2 weeks ago and now it has changed.
I thought that I could just use Quick Mask to manually paint with 100% black or 100% white to adjust the boundaries of the selection and then save that final selection as my alpha channel.
However, I'm discovering that when I do this, I end up getting a weird grey-ish artificat (which incidentally, I can't figure out how to remove it). How I should be properly modifying the selection prior to actually saving it.
This question is more theoretical, as I have found a work around. On a layer, I have a gray color, which I sample, and it becomes the desired Foreground color.
I would like to Fill a Selection in an Alpha Channel with this gray color.
However, when I view the Alpha channel, my forground color is lost to black/white, which I understand, as the Alpha channel is a gray scale image.
But, I am able to sample a gray Swatch to make a Foreground color, but how can I preserve my chosen Foreground gray selected from a Layer? The only way that I know would be to make a new Swatch, and then use that when I am in Channels.
I have a 24bit PNG image to be used as a texture in my little game. I want to blend this texture with other colors which require it to have an extra alpha channel. I did some search online and tried some methods including add another layer and add transparency to the image, but neither worked(after I exported the image to png and reopened it, it still only contains 24 bits for every pixel).
Is there an easy way in GIMP to invert the alpha channel of an image? Transparent should be opaque, opaque should be transparent, almost transparent should be almost opaque, etc.
I have a B&W images. It's actually in RGB but all shades are gray. I would like to create an alpha channel whose values equal the brightness of each pixel. How do I do that?
I'm trying to create an image which emulates a solar corona (it's basically just a blurry circle). It's as easy as making one brush stroke in gimp, but my problem is that i can't get all the channels to be correctly set.
Ultimately i just want to edit the alpha channel, NOT the RGB ones. They should all be pure white, or 255, 255, 255. But for some reason, no matter how much masking or color selection or clicking only the alpha channel and not the RGB ones or anything that i do, i cannot keep the RGB white while editing the alpha channel, every stroke that affects alpha seems to invariably affect the other three.
Thought I'd try Gimp on my new laptop instead of Photoshop. I'm making graphics for a game.
I needed to add an alpha channel to an image and edit it, including pasting into the alpha channel from the clipboard. Easiest thing in the world on Photoshop, but seems utterly impossible on Gimp.
I've looked at a few threads that discuss editing the alpha channel, and they make it sound like rocket science. Notable, most seem to involve juggline multiple other images and then following convoluted pasting operations to get anything down. Or using layer "Masks" which, as best I can see, are impossible to paste into (and I couldn't find how to convert these masks to alpha channels either.)
As it stands, I've failed to get anything onto an alpha channel at all, except some scribble that showed up in the tiny side icon but couldn't be seen in the main image.
I'm new to Gimp, and I'm hoping I've just missed something. What is the straight forward way to edit the alpha channel (drawing on it, pasting into it from the clipboard), and seeing the results at the same time. I've tried everything intuitive and nothing works.
Is it possible to directly edit the alpha channel? I need to edit it for a 3D model I've made, and its showing up as too shiney (The engine is looking at the alpha for reflectivity).
However, I have yet to see a way to edit the alpha channel directly.
Basically I need to be able to add different information into each channel including the alpha without the image being transparent at all.
Not to compare at all, but in photoshop i could work solely in the alpha channel without the RGB channels visible, then enabling the RGB channels would allow me to see the entire image without any transparency.
Basically, i want to be able to use the alpha channel for things other than transparency. For storing different masks in each channel for use in shaders.
I know how to add alpha channel to each layer individually and manually but is there a way to have an alpha channel added to each new layer automatically?
I started using gimp yesterday to remove backgrounds out of images for my website so have done it fine.
But now I clicked on something which reduced the toolbox dialog box to not be as large - ie it does not show you pixels size etc if you select pencil tool now.
Also I open an image and lasso it - then click the quick mask but the pencil tool is not adding any more to the area - it wont draw over or anything. The lock alpha button is on in the layers panel and I cant unlock it.
1.I am working on a project where I need to set all pixels below a level as alpha channel, is there a quick way to achieve this? The level can be both set a prior or adjusted dynamically, the second way is preferred. Right now my workflow includes:1. duplicate layer. 2. use color level in duplicate layer, in menu COLOR -> LEVEL. 3. add alpha mask to original layer 4. copy duplicate layer into the alpha mask of the original. 5. delete duplicate layer. 6. If result is not ok then return to 1.As you can see this workflow is a headache, specially point 6 which is often achieved.
I have some textures, and i am trying to pack them into texture atlas. All of them are RGBA png's generated with PIL (Python Image Lib). I am opening all of them in gimp and copy-pasting them into their new place in texture atlas.
But i have noticed something strange, i am storing specular map in alpha channel of my diffuse textures, and emission value in alpha channel of normal textures.
The problem is, that GIMP does not copy pixels with 0 alpha value into clipboard. So, when i am trying to copy a normal map from source to atlas, and if emission value is 0, then GIMP is not copying anything, i am getting empty layer pasted into my atlas, if there are 0 alpha value pixels in diffuse map they are not copied to destination, even selection outline shows that there are no pixels in places where specular is set to 0.
I have a PNG logo that has anti-aliased letters on a transparent background. In other words, all pixels are white (for example) and either 0% transparent (in the letters) or semi-transparent (in the anti-aliasing). The rest of the image is transparent.
What I'm trying to do is take change the color of the logo. Bucket fill in normal mode changes the alpha value of the semi-transparent pixels to 0% transparent when applying the color--so I loose the anti-aliasing. I did manage to get what I want with bucket fill mode Darken only, but this only works for certain colors on certain other colors (I can change white to any other color, but not vice versa).
Is there a straightforward way to fill a color while keeping the alpha channel intact? I tried all the modes, and also modifying the Fill transparent areas, but don't really understand them to figure out if one does this in the general case.
I'm trying to put a pattern around an object that needs alpha channel in the middle, but when I make a new layer and add the pattern, then select the area and use "Color to Alpha" it doesn't work. The pattern in that area is only turn slightly darker, not alpha channel.
For years I've been using various image editors, often in combination. That is, I do simple stuff as copy / paste and repositioning of elements in one editor and subsequently open the image in a more advanced editor for proper paintwork. Currently I'm using the Gimp for the latter. Color layers work brilliantly. However, I have big problems with my alpha channel--I've found no way to edit it within Gimp and I've found no way to import a revised version that I've edited in another image editor. There must be solutions to both challenges.
The editing I require is piece-of-cake in basic image editors--I simply want to move a transparent region a bit to the left. That should be a simple rectangle selection and then shoving it (mouse or arrow keys) to where I want it. Alternatively I could import my edited alpha channel image as I'm used to doing in other editors. Well, the Gimp will accept the image as a layer all right but I haven't succeeded in making the Gimp import my grayscale image as an alpha channel. I get a grayscale non-transparent layer instead.
So, I've got a perfectly good alpha channel that needs a minor tweak. It loads as intended in Gimp. How to perform basic editing of this alpha channel layer or tell me how to import a revised version and tell Gimp that this image should be interpreted as an alpha channel?
I'm trying to make a texture for a model in a video game, and I want some of it to be transparent. This is done by editing a text file that tells the model to use the textures alpha channel. things in the alpha channel that are white are transparent and things that are black aren't.
But I don't really know how to edit the textures alpha. Here is a video I've seen that explains how to make one in photoshop: [URL]......
How to do exactly what he does in gimp? whenever i duplicate one of the rgb layers, it isn't black and white like it is in ps. i'm also not sure how to have it turn into the alpha.