Post Reply 

How to create a variable transparency

Sep 4, 2013, 12:30
Post: #1
How to create a variable transparency
Hi

I'm sure 'variable transparency' is not the right way of putting this.

I have an image which has some text in white. However because of the aliasing the text is not 100% white against the background (black). Rather; the edges are shades of white.

I want to convert the image so that the text is transparent. If the text was 100% white it would be simple. Colors.. Colors To Alpha. However that doesn't work as it doesn't deal with the shades of white around the edges of the text.

I want the shades of white to be transparent with the same degree of opacity as they white. So the white in the image is 100% transparent and a pixel which is say light grey to be 90% transparent. (The end image is going to be used as a webkit mask; showing the background behind the masked element).

I don't know where to start with this. I know PNGs support 8 bit transparency so it should in theory be possible.

The sample file is an example of the type of file I want to convert.

Many thanks

--Justin Wyllie


Attached File(s) Image(s)
   
Find all posts by this user
Quote this message in a reply
Sep 4, 2013, 13:49 (This post was last modified: Sep 4, 2013 14:11 by justinwyllie.)
Post: #2
RE: How to create a variable transparency
Hi ofnuts

Thanks.

OK. Thanks. It was not Color to Alpha that was my problem but the other aspects of the problem. As you say Color to Alpha does what I want it to do.

My problem was making the Text transparent - not the background.

Anyway I've got there in the end. I used Colour to Alpha on the text and a second layer underneath to confirm that the anti-aliased pixels were semi-transparent.

Thanks for your help

--Justin Wyllie
Find all posts by this user
Quote this message in a reply
Sep 4, 2013, 13:57 (This post was last modified: Sep 4, 2013 14:10 by justinwyllie.)
Post: #3
Smile RE: How to create a variable transparency
Hi ofnuts

Thanks.

OK. Thanks. It was not Color to Alpha that was my problem but the other aspects of the problem. As you say Color to Alpha does what I want it to do.

My problem was making the Text transparent - not the background.

Anyway I've got there in the end. I used Colour to Alpha on the text and a second layer underneath to confirm that the anti-aliased pixels were semi-transparent.

Thanks for your help

--Justin Wyllie


Attached File(s)
.xcf  test.xcf (Size: 6.93 KB / Downloads: 31)
Find all posts by this user
Quote this message in a reply
Post Reply 


Possibly Related Threads...
Thread: Author Replies: Views: Last Post
  Create a Rift AMaskedMan 1 179 Apr 20, 2018 15:47
Last Post: paynekj
  (Probably)easy transparency / background question Matthew Cole 1 194 Mar 13, 2018 18:26
Last Post: ythgilb
  create layer for laser cutting jigsaw carolchi 1 253 Dec 25, 2017 23:46
Last Post: ofnuts
  Checkerboard transparency toggle rahdad1 2 435 Oct 9, 2014 16:14
Last Post: rahdad1
  how to create logo for watermark purpose? kenny1999 5 667 Sep 24, 2014 18:16
Last Post: kenny1999

Forum Jump:


GIMP ForumPortalArchiveContactTermsRSS