Transparency and PNG format

[graham samuel]

Thanks to all who replied to this, specially Ken Ray who gave me a  
quick way out of my problem and answered my other question too.  This  
is by no means the first time I've been happy to thank Ken for a  
RunRev solution. I really appreciate it.

Graham

(OT rant: I had tried the Help files in Photoshop Elements but I just  
gave up because they don't give you, AFAIK, a step-by-step guide to  
making part of an image transparent. To my mind, Photoshop has been  
so successful that it's created its own vocabulary which is hard for  
amateurs to grok, but their huge success makes them thinking they're  
speaking English: perhaps my favourite is 'Unsharp mask' which  
actually sharpens! ).


> Message: 10
> Date: Tue, 29 Nov 2005 16:37:10 -0600
> From: Ken Ray <kray at sonsothunder.com>
> Subject:
> To: Use Revolution List <use-revolution at lists.runrev.com>
> Message-ID: <BFB23436.30AAB%kray at sonsothunder.com>
> Content-Type: text/plain;	charset="US-ASCII"
>
> On 11/29/05 4:05 PM, "graham samuel" <graham.samuel at wanadoo.fr> wrote:
>
>
>> I've now started to using PNGs rather than GIFS, and I can give them
>> transparent backgrounds in exactly the same way as the GIFs
>> (GraphicConverter on the Mac is really good for this - a lot simpler
>> than Photoshop Elements... but I digress).
>>
>
> That's the problem, unfortunately - you need to have a true alpha  
> channel in
> order to have the PNG be transparent. To do this in  
> GraphicConverter takes
> only one more step.
>
> After you've used the wand tool to drop out the transparent color,  
> go to the
> Picture menu, down to Alpha Channel, and select Create Alpha/Mask  
> Channel
>
>> From Transparency.
>>
>
> You won't notice anything happen in GraphicConverter, but when you  
> save it
> out, you'll have the proper transparency in Rev/MC.
>
>
>> (This leads me to ask if
>> is there any disadvantage to using GIFs over PNGs - I kind of thought
>> there was, but I'm no longer sure why).
>>
>
> Yes, with GIFs you only get 256 colors, whereas with PNGs you get  
> 24bit
> color. That's the primary reason.
>
> Have fun,
>
> Ken Ray
> Sons of Thunder Software
> Web site: http://www.sonsothunder.com/
> Email: kray at sonsothunder.com



----------------------------------------
Graham Samuel / The Living Fossil Co. / UK and France