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+--- Thread: Making an image semi-transparent… Or is that semi-opaque? (/Thread-Making-an-image-semi-transparent%E2%80%A6-Or-is-that-semi-opaque)
Making an image semi-transparent… Or is that semi-opaque? - HavingTooMuchFun - 09-25-2018
What I’m trying to do is make an entire image SHEER, in other words see-through, but with all the colors maintained. Using the opacity control on the layers palette it looks like I’m doing that, the gray checkerboard appears underlying the image, but when I try to copy or clone that image onto another one, it goes on completely opaque, no matter how low I take the opacity! BUT, if I save the image as a PNG, and re-import it, then it can be copied or cloned and it IS sheer.
Clearly, I’m making some sort of stupid error here; could somebody please tell me what it is, lol?
Also: I’ve tried copying the sheer image into the clipboard of the brush pallete, but the result is also always opaque; is that fixable?
For bonus points: Is there a way to make only PART of an image see-through? Not colorless, just SHEER. Taking a color to alpha sometimes creates exactly that effect, by accident as far as I can tell, because I can’t make it do that deliberately…?!
RE: Making an image semi-transparent… Or is that semi-opaque? - rich2005 - 09-25-2018
Is a water glass half full or half empty? Depends on your viewpoint.
You need to experiment with Gimp a little.
Have a base layer. Add another image layer. Add a layer mask (white). Apply a black to white gradient in the layer mask
Full transparent one side (white), fully opaque other side (black) varies between.
![[Image: Dif4vcg.jpg]](https://i.imgur.com/Dif4vcg.jpg)
Could I make that into a clipboard brush? Yes, easiest is copy a single complete layer, so a new-from-visible layer, then copied. Working as a brush.
![[Image: zVmD7dU.jpg]](https://i.imgur.com/zVmD7dU.jpg)
RE: Making an image semi-transparent… Or is that semi-opaque? - Ofnuts - 09-25-2018
(09-25-2018, 04:41 PM)HavingTooMuchFun Wrote: What I’m trying to do is make an entire image SHEER, in other words see-through, but with all the colors maintained. Using the opacity control on the layers palette it looks like I’m doing that, the gray checkerboard appears underlying the image, but when I try to copy or clone that image onto another one, it goes on completely opaque, no matter how low I take the opacity! BUT, if I save the image as a PNG, and re-import it, then it can be copied or cloned and it IS sheer.
What is the type of the image you are copying to? In color-indexed images (GIF), opacity isn't progressive.
RE: Making an image semi-transparent… Or is that semi-opaque? - HavingTooMuchFun - 09-25-2018
Sorry, that was a lot of terms that I'm not familiar with and steps that I don't know how to take!
Why does my "sheer" image act like it's opaque when I try to copy or clone from it unless I export and then re-import it?
Can I get part of an image to be "sheer" selected by color, like color to alpha sometimes accidentally does?
Copying to the brush palette clipboard in the usual way (and it is from a single complete layer) turns a sheer image opaque; how do I work around that?
RE: Making an image semi-transparent… Or is that semi-opaque? - rich2005 - 09-25-2018
As Ofnuts said, it all depends on the mode of the image - RGB or Indexed.
Sheer is not a term I fully understand, so I am assuming it is semi-transparency.
Quote:Why does my "sheer" image act like it's opaque when I try to copy or clone from it unless I export and then re-import it?
Starting with an image that contains transparency, I can copy then paste or click-and-drag, either way
ends up the same, the transparency is there. Can you explain a bit more your "copy or clone process"
This is what I get: https://i.imgur.com/bCu3gka.jpg
Quote:Can I get part of an image to be "sheer" selected by color, like color to alpha sometimes accidentally does?
Nothing in Gimp is accidental. It all reverts to the 'user.
Going back to layer masks and white is transparent / black opaque, Shades of grey are semi-transparent. Colour pick to make a selection, Make a mask using the from selection option. Then edit the layer mask (brightness/contrast..) to get a decent semi-transparent image.
example: https://i.imgur.com/IEKdvwM.jpg
Quote:Copying to the brush palette clipboard in the usual way (and it is from a single complete layer) turns a sheer image opaque; how do I work around that?
You can see from previous post that an image with transparency retains it as a clipboard brush. It is probably the Mode (RGB/Indexed) you are using.
Asked this before but what version of Gimp are you using? (2.8 / 2.10) It tell you on the start up splash, so no excuses.
RE: Making an image semi-transparent… Or is that semi-opaque? - HavingTooMuchFun - 09-25-2018
(09-25-2018, 05:36 PM)Ofnuts Wrote:(09-25-2018, 04:41 PM)HavingTooMuchFun Wrote: What I’m trying to do is make an entire image SHEER, in other words see-through, but with all the colors maintained. Using the opacity control on the layers palette it looks like I’m doing that, the gray checkerboard appears underlying the image, but when I try to copy or clone that image onto another one, it goes on completely opaque, no matter how low I take the opacity! BUT, if I save the image as a PNG, and re-import it, then it can be copied or cloned and it IS sheer.
What is the type of the image you are copying to? In color-indexed images (GIF), opacity isn't progressive.
You must’ve posted right when I did, I didn’t even see you there, sorry! I don’t know what type the image is, or how to find that out… whatever Gimp gave me when I created a new one? Everything I’m saving is JPG or PNG, so I’m guessing it’s one of those. It's all RGB.
Rich:
I don't know what is up with Gimp... once I start using a brush, EVERY tool meant to draw will be that brush instead until I restart the program...??!!!!
All my images are RGB.
"Sheer" is like stained glass; you can see through it, but it has color.
To copy, I click "copy" on the first image and then click "paste" on the second image. To clone, I click "clone," command-click where I'm cloning from and move the cursor over where I'm cloning to. I'm getting a result as if an opaque image had been copied or cloned over a second image, 100% of the time... until I export and re-import, and then it acts in the expected way for a "semi-transparent image."
Please DON’T go back to masks, LOL! I have no idea what they are, or how to use them, I’ve never used them, and I’m not using them for this project. All I’m talking about here is doing color to alpha, which 95% of the time produces a clear and colorless area, like a window in your house, and 5% of the time produces a transparent but COLORED area, like stained glass. If this is something that I’M doing, then please tell me how I’m doing it so that I can duplicate it! :-)
I’m using Gimp 2.8.22, RGB for every image, and these are the results I'm getting. Maybe some obscure setting somewhere?
RE: Making an image semi-transparent… Or is that semi-opaque? - HavingTooMuchFun - 09-25-2018
I decided to try doing a few rounds of color to alpha to see if it would do the weird thing it sometimes does, and it DID! In this first image, you can see that I have selected the RED blob, and brought up the color to alpha box… but the box is inexplicably showing that BLACK is selected, although it’s not, I did nothing in the alpha box to make it show black, there is no black in this image, and the previous selection was BLUE, not black. And here’s where it gets tricky: the alpha box is ALSO showing a checkerboard overlay on the red… NOT an all-gray checkerboard REPLACING the red, but an OVERLAY:
![[Image: Red%20selected%20alpha%20says%20black%20...j8l5iv.png]](http://img.photobucket.com/albums/v247/Omniverse/Red%20selected%20alpha%20says%20black%20red%20becomes%20sheer_zpsugj8l5iv.png)
I click OK, and then I have this; note that the red blob has a checkerboard OVERLAY, rather than what color to alpha normally does, which would be replacing it with an all-gray checkerboard meaning that it is now transparent:
![[Image: Result%20red%20is%20sheer_zpsvvtro2bh.png]](http://img.photobucket.com/albums/v247/Omniverse/Result%20red%20is%20sheer_zpsvvtro2bh.png)
The red blob is now SHEER, as if it was a stained glass pane. Need more proof? Here is a boldly-patterned image:
![[Image: squiggle_zpsfc8jvoqa.png]](http://img.photobucket.com/albums/v247/Omniverse/squiggle_zpsfc8jvoqa.png)
And here is what I get if I copy the blob image over the black-and-white one… Note that the black lines show through the red, so the red blob is in fact SHEER, as if it was stained glass:
![[Image: Squiggle%20shows%20through%20the%20red_zpseifgoxtn.png]](http://img.photobucket.com/albums/v247/Omniverse/Squiggle%20shows%20through%20the%20red_zpseifgoxtn.png)
If you can tell me what happened here, so that I can reproduce it at will, I will be eternally grateful!
RE: Making an image semi-transparent… Or is that semi-opaque? - rich2005 - 09-26-2018
Quote:The red blob is now SHEER, as if it was a stained glass pane. Need more proof? Here is a boldly-patterned image:...
It goes back to nothing in Gimp is accidental, It all comes from the user.
Quote:..If you can tell me what happened here, so that I can reproduce it at will, I will be eternally grateful!
This example (using Gimp 2.8) top to bottom, using the same colours as your screenshot. There is a selection in place.
https://i.imgur.com/oATDU00.jpg
1. If you colour pick the 'red' you will find it is not pure red, it strays across to the 'black' side.
2. A color-to-alpha (C2A) with black as the colour (white is usually the default) will remove the 'black' element leaving a semi-transparent pure red behind.
3. That lets any layer underneath to show through.
What essential are you missing? You can change the C2A colour by clicking in the dialogue, then select some other colour, including color-pick that off-red. Which will give total transparency of the selection.
https://i.imgur.com/09kmkJM.jpg
You might not like any mention of masks, but the alpha-channel for image transparency is essentially a built-in mask. You can not really have a transparent image, your software has to use that mask (and some do not)
I know the Gimp docs https://docs.gimp.org/2.8/en/ are not easy to trawl through, but all the essentials are there. https://docs.gimp.org/2.8/en/plug-in-colortoalpha.html
If you do not like the on-line help and a Mac is unlikely to get local help installed, there is a good pdf, with a searchable index, here: http://gimp.linux.it/www/meta/
Going back to one of your earlier posts. Jpeg images do not support transparency. Save all your work-in-progress as a Gimp .xcf file. Then export as a png which does keep the transparency.
RE: Making an image semi-transparent… Or is that semi-opaque? - HavingTooMuchFun - 09-26-2018
FANTASTIC! I experimented a little bit, and by having the “from” color be black or white, almost any color can be made “semi-transparent.” The very few exceptions can also be transformed by adding an infinitesimal amount of black or white, so little that you can’t even see it. Thank you so much for explaining this, this will be a wonderful addition to my artwork!
I’m still struggling with some of the original issues of this post, though:
Why are images that I have made semi-transparent using the opacity control on the layers palette copying or cloning as opaque unless I export and re-import them?
Why are semi-transparent images that are in the clipboard of the brushes palette being applied as opaque?
How do I go from using the brushes palette back to normal pencil function? Currently I’m having to restart Gimp to make that happen.
RE: Making an image semi-transparent… Or is that semi-opaque? - Espermaschine - 09-27-2018
(09-26-2018, 09:48 PM)HavingTooMuchFun Wrote: Why are images that I have made semi-transparent using the opacity control on the layers palette copying or cloning as opaque unless I export and re-import them?
Why are semi-transparent images that are in the clipboard of the brushes palette being applied as opaque?
You can get a transparent clipboard brush from a layer with lowered opacity by using the 'Copy Visible' command.