[chadfree] Re: Photo program question

Think we need to know what you're trying to achieve ... from this it sounds 
like you're trying to create an image with transparent background ... 
that's not really possible by just deleting the background, it will work in 
the image programs proprietary format, but it will not work with other 
formats unless you use the right file format, AND do the right tricks to 
make it ... it requires a special file format and image manipulation to 
achieve it...

GIF, PNG, and JPEG2000 are the only file formats that support transparent 
background ...

Just a quick run down of SOME of the features these formats offer:

GIF (more correctly GIF89a) only supports 8 bit paletted images, but it 
allows you designate 1 of those colors for transparency or 1 color for 
inverted (which will invert whatever background it's placed on) [gif also 
supports animation, but that's beside the point in this case]. Typically 
images for the web have been made in gif because of the transparency 
feature. How it works is to paint the transparent parts in a color that 
isn't used in the rest of the image, and then designate that to being 
transparent ...
BUT, because of the low color count, GIF is only useful for lineart, text, 
and very small images with very few colors (the windows icon format  used 
up till Windows 95 is actually based upon the GIF format). For any other 
form of imagery, you need to use any other format (otherwise it will 
seriously be ugly)...

PNG is very poorly supported in most programs. It was meant to be the heir 
to GIF (both formats are invented by CompuServe). It offers a 24 bit (16 
million colors) full-color palette, and transparency. The transparency is 
made the same way as in GIF: 1 color is designated to be transparent. BUT, 
the problem with PNG is that it's very, very poorly supported, in both the 
imaging programs and the programs that are to display them. Generally the 
transparency don't work at all because the programs don't support it. I've 
yet to find a program other than Photoshop where PNG transparency actually 
works (properly anyway).
More info: http://www.libpng.org/pub/png/

JPEG 2000 is very new. Only been about for 2-3 years (considering PNG and 
GIF have 10 and 20 years on the hiney...). It's the heir to the JPEG 
format, offers better quality, more colors (up to 48 bit colors), and 
transparency and other fancy features that used to be only possible with 
proprietary formats.
In a JPEG2000 file, you mask out the part that you want transparent (using 
your programs mask tool), then save it. The mask will be saved with the 
image, and when viewed, the masked part will be transparent. This atleast 
is how Corel describes the procedure in Photo-Paint 12...
You can read about the JPEG 2000 format here:
http://www.jpeg.org/jpeg2000/index.html


HTH

Rene

At 17:57 18-04-2004, you wrote:
>Thank you Rene, I'll give it a try.  It does seem to me that this should be
>something that is in most photo programs but that I just can't/couldn't
>figure it out.  In Infanview it did delete the background but when I saved
>the picture it wound up having a white square background.  So I was afraid
>that would happen with the Photo Shop too.  In Photo Impression, I could cut
>around the picture but when I click either "cut" or "crop" it deletes the
>picture instead of the background!  LOL!  So I figure I am just doing things
>wrong.
>
>I'll try saving the picture with the grey and white checks and hopefully
>I'll have no background.
>
>Thank you!
>
>Peggy

-- 
Rene Brehmer
aka Metalbunny

~ If you don't like what I have to say ... don't read it ~

http://metalbunny.net/
References, tools, and other useful stuff...
Check out the new Metalbunny forums @ http://forums.metalbunny.net/


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