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Pylon
Joined: 15 Jan 2010
Posts: 1
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Posted: Fri Jan 15, 2010 8:40 pm Post subject: Alpha Transparent PNG 8? |
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Hello to all,
I am going nuts here and I can not understand if what I am trying to do is actually possible or not.
What I want is to create a simple icon which has a slight white gradient that ends in transparency.
However when I save the file the result I want is without "matte" since the background color of my web page is going to dynamically change.
So this leaves me with the option of using png24.
However I want to use png-8 and I know it supports alpha-transperancy.
But how do I achive this in photoshop cs4?
So I started to do some searches on the net and found out that you can actually use alpha channels ... but how?
I would be more than happy if someone could post a link on a tutorial or some other usefull information working with alpha-transparent png files suitable for web pages.
Cheers! |
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jbriant
Joined: 30 Jan 2010
Posts: 1
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Posted: Sat Jan 30, 2010 11:48 pm Post subject: |
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I'm a total noob too, but here's what I did.
Create a new file. This made me a layer called "Background".
Create a new layer. It should be transparent.
Delete the background layer.
You should now have a layer that is transparent.
Draw what you want on it.
Go to File>Save For Web And Devices
PNG-8 will be one of the options. PNG-8 is indexed color. You may need to tell it how many colors you have. It stayed at 256 for me, even though I only had 15. When I set it to 15, my file was a lot smaller. You might want to work in index color the whole time using the Image>Mode>Indexed menu option.
Beware that if you use indexed color, then you have a PNG8 file if you just do "Save As" and choose "PNG", but it will be *full* of metadata.
jamie |
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Patrick
Administrator

Joined: 14 Feb 2003
Posts: 11945
Location: Harbinger, NC, U.S.A.
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Posted: Sun Jan 31, 2010 12:11 pm Post subject: |
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Matt
VIP

Joined: 24 Sep 2007
Posts: 3515
Location: Haverhill, UK PS Version: Lightroom 5, CS4 & Elements 11 OS: Windows 8.1
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Posted: Mon Feb 01, 2010 9:25 am Post subject: |
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Hi Pylon,
PNG-8 only has a one bit transparency capability meaning a pixel is either opaque or transparent. It's not best suited to gradients unless you use a matte but that's no good either if you're employing a dynamic background that's prone to change colour. A small JPEG or PNG-24 will be your best options although filesize won't be as efficient as GIF or PNG-8.
Hope that helps _________________ Matt
3photoshop.com
http://www.3photoshop.com |
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JimDandy
Joined: 25 Feb 2010
Posts: 1
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Posted: Thu Feb 25, 2010 4:24 pm Post subject: |
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Um, I just have to interject that this is wrong. Google around for PNG-8 and "alpha transparency." Fireworks or a tool called ImageAlpha can make RGBA, adaptive-palette PNG-8s for the web. That's up to 256 levels of transparency.
mattyboy777 wrote: | Hi Pylon,
PNG-8 only has a one bit transparency capability meaning a pixel is either opaque or transparent. It's not best suited to gradients unless you use a matte but that's no good either if you're employing a dynamic background that's prone to change colour. A small JPEG or PNG-24 will be your best options although filesize won't be as efficient as GIF or PNG-8.
Hope that helps |
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