jgt1942 Posted May 30, 2018 Posted May 30, 2018 I cannot find the how-to for making the background transparent and saving it so I can use it in other applications. I have a few B&W images, e.g. the black image is on a white background. I want the white to be transparent. Quote
jgt1942 Posted May 30, 2018 Author Posted May 30, 2018 I just found tanel_pluginpack_20120305.zip and installed it. I opened my image and selected it I then clicked Effects > Color > Color to Alpha The "Color to Alpha" window opens, now I can see my image and the white background is now transparent I saved the image as a PNG file I then attempted to use the image by inserting it in a PDF file but the entire image that is inserted is black. What the heck did I do wrong? Quote
BoltBait Posted May 30, 2018 Posted May 30, 2018 When saving as PNG, make sure to choose "auto" or "32-bit" to preserve transparency. Quote Download: BoltBait's Plugin Pack | CodeLab | and a Free Computer Dominos Game
jgt1942 Posted May 30, 2018 Author Posted May 30, 2018 OK where do I choose "auto" or "32-bit"? When I saved I clicked File > Save As > used the same folder as the original but changed the name so I could keep the original file. Sorry to be so dense. Quote
BoltBait Posted May 30, 2018 Posted May 30, 2018 15 minutes ago, jgt1942 said: OK where do I choose "auto" or "32-bit"? After you choose the filename, click OK and you'll get the "Save Configuration" screen. This asks the bit depth. Quote Download: BoltBait's Plugin Pack | CodeLab | and a Free Computer Dominos Game
jgt1942 Posted May 30, 2018 Author Posted May 30, 2018 AH yes I did see that window. Originally I had selected "Auto-detect", I now selected 32-bit but still, I get a black image when I use it or view it with IfranView. In the "Save Configuration" window where I can select the "Bit Depth" the background in the preview looks like it is transparent (it looks like a checkerboard). I've got to run and will not be available for several hours. Much thanks for the feedback. Quote
BoltBait Posted May 30, 2018 Posted May 30, 2018 If you want, you can post one of your transparent images here and someone will be glad to check to see if it is indeed saving in the proper format. Other than that, I'm guessing that the issue is with the other software and not Paint.NET itself. Quote Download: BoltBait's Plugin Pack | CodeLab | and a Free Computer Dominos Game
jgt1942 Posted May 30, 2018 Author Posted May 30, 2018 (edited) Great suggestion. I've uploaded two files test01.png (the first file below) is the original file test01-trans.png is the file I've modified and should have a transparent BG. I'm surprised that it displays in the webpage. When I attempt to insert it in another file (PDF for example) or open it with IframView all I see is a black square. Edited May 30, 2018 by jgt1942 identify which image is the original (source) file Quote
jgt1942 Posted May 31, 2018 Author Posted May 31, 2018 OK I think I was doing something stupid but I'm not sure what I did. I've managed to make the background transparent just by repeating what I think I've been doing all along. Here is the latest file and it has the transparent BG. Quote
Roly Poly Goblinoli Posted July 16, 2018 Posted July 16, 2018 You can convert black-and-white photos to have transparent backgrounds with 100% accuracy using the Switch Gray to Alpha plugin. Quote
windydick Posted August 15, 2018 Posted August 15, 2018 Hi, I'm a newbie finding my way round, graduating from W10 Paint with some difficulty. Alphas and plug-ins are way above my pay-grade at mo. What you could try is magic wand a white portion, either contiguous or global as appropriate. Then simply delete the magic wand selection, which then becomes transparent. Also try try tinkering with tolerance for the magic wand selection as there's no gradient between solid off-white and transparent no pixel. My problem why I'm here is dear old Paint's transparent/opaque toggle, which I can't find here. Even copy/paste or move a selection on a transparent background obliterates everything in the selection area. You paste transparency, not nothing, if you see what I mean. Paste in new layer works a bit clunky, but even more fiddly to "toggle" back to opaque. Quote
toe_head2001 Posted August 15, 2018 Posted August 15, 2018 3 minutes ago, windydick said: ... You paste transparency, not nothing ... When you paste, you're overriding the RGBA values, rather than compositing them. The RGBA values are composited when using layers, and that's why pasting into a new layer works the way you expect. Quote (September 25th, 2023) Sorry about any broken images in my posts. I am aware of the issue. My Gallery | My Plugin Pack Layman's Guide to CodeLab
windydick Posted August 15, 2018 Posted August 15, 2018 This is .png of magic wand>delete on your first sample image. I think it's a lot better than your second image if you look at the tongue zig-zag, etc. Confusingly it displays with a PDN chequer background in Honeyview, but not in Windows Photo. I've just made a .pdn with a white background layer, but I find that .pdn is not an allowed file, which I find really, really, really strange!!! I've a lot to learn! If you're interested, here's a link to the .pdn file on my Google Drive; https://drive.google.com/open?id=1gNOqll5_ON2q0FQRn4gu33ZTMkGpAxgu Quote
MJW Posted August 15, 2018 Posted August 15, 2018 The Magic Wand approach is a bad way to make the background transparent for a black-on-white image like the snail drawing. Do as @Joshua Lamusga suggests: use a plugin that converts white to transparent, such as Switch Gray to Alpha or Color Clearer. There are a number of others that will also work, such as the Grim Color Reaper. The problem with using the Magic Wand is that most black-on-white images contain gray pixels on the edges of the black areas, to make the edges look smooth, not jagged. If the tolerance of the Magic Wand is set high when selecting the background, so that all non-black pixels are selected, these pixels will be deleted, distorting the image and leaving a jaggy edge. If the tolerance is set low, so that only the truly white pixels are selected, the gray pixels will remain, and if the edited image is placed over a colored background, will be clearly visible as a jagged gray halo. Using one of the white-to-transparent plugins will convert the gray pixels to partially-transparent black pixels. Quote
windydick Posted August 15, 2018 Posted August 15, 2018 Hi, yes, MJW - I guessed and accept the deficiencies you describe. However, the result on my attempt is clearly considerably better than jgt1942's second sample above - compare almost anywhere on the image, which shows the faults you describe. OK, on a solid white background. Horses for courses, I suppose; probably much worse results with grey-scale photos, and coloured background. wd Quote
MJW Posted August 15, 2018 Posted August 15, 2018 @windydick I suggest you just bite the bullet and install a plugin. It's not that hard to do, and once you have the plugin, eliminating the white background will be easier, and much better, than using the Magic Wand. You can install BoltBait's plugin pack, which includes Switch Gray to Alpha, among many other useful plugins. The plugin pack has an installer, which will do most of the work for you. Installing the plugins should be as easy as, or easier than, installing Paint.NET. Running the plugin is as easy as running a built-in effect. You won't even know the difference. Quote
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