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TOPIC: PNG images don't show up with transparent backgrounds

Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110176

  • jwrl
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Well, I've just deleted a post that I'd just put up. The reason? It's 1 am Monday morning my time and I should never post when I'm that tired.

Steve, could you please post a step-by-step of what it is that you're doing with the PNG file inside Lightworks? How did you import it, and what were your subsequent actions? We're almost at a dead end here.

Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110183

  • Steve Esposito
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jwrl wrote:
RWAV and donkpow, I don't believe that Steve Esposito has attempted to use the graphic at all.

Steve Esposito wrote:
I did not even add it to a timeline yet, I just showed you how it comes up.

Did you read my post and follow the step-by-step, Steve? If you do exactly what's outlined there with the graphic as you uploaded it here it will absolutely definitely work. Looking at a graphic with transparency by itself may not always look as you expect it to.

Don't assume anything, just follow those steps.


Okay, I did exactly as I said. I have not yet used it in a timeline because it looked so bad in the editor so I went back to GIMP and did the things described earlier to get a file that Lightworks displays properly.

Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110189

  • Steve Esposito
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jwrl wrote:
Well, I've just deleted a post that I'd just put up. The reason? It's 1 am Monday morning my time and I should never post when I'm that tired.

Steve, could you please post a step-by-step of what it is that you're doing with the PNG file inside Lightworks? How did you import it, and what were your subsequent actions? We're almost at a dead end here.


1. Made PNG from a JPEG in GIMP 2.8
2. Opened Lightworks
3. Opened an existing project
4. Clicked on "files to import"
5. Took a while finding the picture I wanted, because the trees are supposed to be deleted.
6. Closed Lightworks
7. Went back into GIMP and looked at picture, was fine there.
8. Opened file in Windows Photo Viewer, looked fine there.
9. Opened Lightworks, went through above steps and went one step farther, clicked "import" to bring the file into the project.
10. Double clicked on the photo in the "clips" window
11. Editing window opened and I shrieked "that looks horrid" and closed the project
12. Posted to the forum.
13. Went back into GIMP and used a different method to edit the image, imported it into Lightworks
14. Started this merry go round of Q/A
15. Zipped the file in Win 8.1 utility, it is here

If I am unknowingly using nodes routing in this process of merely viewing a file in the edit window, so be it, I am sure I have used a bunch of other processes that I am unaware of too.
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Last Edit: 3 years, 11 months ago by Steve Esposito.

Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110190

  • donkpow
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I have the file. Let me look at it.
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Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110191

  • Steve Esposito
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RWAV wrote:
Because I think donkpow wants to test the idea that posting as an attachment changes the .png file.

You write that you don't use routing. You may not know it but if you have made an effect, yes you do. At this stage it may help if you were to watch the effects tutorials.

I did not even add it to a timeline yet, I just showed you how it comes up
Where???? in a LW viewer??


I had no idea that I made an effect by opening a picture to the blue bordered edit window and did nothing else with it.

Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110192

  • donkpow
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Yes, this is the picture from the zip file installed on V1 with no effects. You can clearly see the trees.


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Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110193

  • Steve Esposito
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Yes, just like in this screenshot I posted yesterday.
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Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110195

  • donkpow
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Here is the same file installed to the timeline on V1 over V2 with a blend effect.


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Now the question is, why does that which was erased from the image continue to remain? This is what I was getting at. It's probably technical stuff, scientific like. Big words like premultiply, etc. Whatever it is, I'm going to find out.

Thanks for giving me that picture in a zip file. At least I know that the site software is not converting the image to a different type of png.
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Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110196

  • donkpow
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Steve Esposito wrote:
Yes, just like in this screenshot I posted yesterday.
Yes. Let me have time to find the answer. I am not an expert. Sorry.
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Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110198

  • donkpow
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Here is what we know. When I separate the alpha channel layer from the png.


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Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110200

  • donkpow
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I am confident the site software has converted the first image shared by Steve. I can prove it or you can just take my word. What that means is, if anybody has this same kind of issue, forum users cannot evaluate the file unless it is in a zip folder.
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Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110204

  • donkpow
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From what I can find, transparency in raster images can be created with transparent pixels or an alpha channel. It appears that GIMP is using transparent pixels in the absence of an alpha channel. In other words, when you erase parts of a 24 bit image, GIMP 'paints' a transparent pixel. When you export said image as png with transparency, you get a 32 bit image with transparent pixels. I am not an expert and this is what I see. If I am wrong, I need somebody to tell me.

If you want to have a 32 bit png that has complete and irrevocable transparency, add an alpha channel before you start 'erasing' in GIMP. Export with the correct settings. Then it will turn out okay.

Apparently, the thumbnail and preview in Lightworks of a png that has been 'painted' with transparent pixels, do not show the transparent pixels. However, a blend applied between fg and bg does show the transparent pixels. By design or omission? I don't know.

To be concise, in order to create your png with transparent alpha, add an alpha channel before editing in GIMP.
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Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110206

  • Steve Esposito
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donkpow wrote:
From what I can find, transparency in raster images can be created with transparent pixels or an alpha channel. It appears that GIMP is using transparent pixels in the absence of an alpha channel. In other words, when you erase parts of a 24 bit image, GIMP 'paints' a transparent pixel. When you export said image as png with transparency, you get a 32 bit image with transparent pixels. I am not an expert and this is what I see. If I am wrong, I need somebody to tell me.

If you want to have a 32 bit png that has complete and irrevocable transparency, add an alpha channel before you start 'erasing' in GIMP. Export with the correct settings. Then it will turn out okay.

Apparently, the thumbnail and preview in Lightworks of a png that has been 'painted' with transparent pixels, do not show the transparent pixels. However, a blend applied between fg and bg does show the transparent pixels. By design or omission? I don't know.

To be concise, in order to create your png with transparent alpha, add an alpha channel before editing in GIMP.


GIMP says it does that automatically:
docs.gimp.org/en/gimp-layer-alpha-add.html
7.33. Add Alpha Channel

Add Alpha Channel: An alpha channel is automatically added into the Channel Dialog as soon as you add a second layer to your image. It represents the transparency of the image. If your image has only one layer, this background layer has no Alpha channel. In this case, you can Add an Alpha channel with this command.


However, there is an option to add an alpha layer manually. I guess that is what Lightworks wants?
Last Edit: 3 years, 11 months ago by Steve Esposito. Reason: added info

Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110209

  • donkpow
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Add Alpha Channel: An alpha channel is automatically added into the Channel Dialog as soon as you add a second layer to your image. It represents the transparency of the image. If your image has only one layer, this background layer has no Alpha channel. In this case, you can Add an Alpha channel with this command.
Highlight for focus. If you open a single layer image in GIMP and begin to erase, no alpha channel is present. However, you can add an alpha channel before you erase and then you will not have to worry about the trees staying in the image. They won't be there. If you don't add an alpha channel, the trees are painted over with transparent pixels.
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Re: PNG images don't show up with transparent backgrounds 3 years, 11 months ago #110210

  • donkpow
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However, there is an option to add an alpha layer manually. I guess that is what Lightworks wants?
Well, either way. You can see when you actually use the image with a blend, it works fine. Lightworks just isn't giving you preview in the same manner as a graphics viewer. I don't know if it has to be that way or not.
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