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Posted on 14/05/09 11:47:49 AM |
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tooquilos
Wizard of Oz Posts: 2918 Reply  |
Can anyone clarify/explain this to me?
Few questions here, which Im hoping someone maybe able explain to me. 1. When saving as a .png file, a window with 2 options comes up (see attached image) None and Interlaced. What is the difference? 2. When saving as a .TIFF file, the dialogue box presents 4 options - None, LZW, ZIP and JPG. What differences do they all have? Still on the .TIFF files - Interleaved or Per Channel..what are benefits and disavantages of these. thanking you in advance Anna   _________________ Dorothy: Toto, I've a feeling we're not in Kansas anymore |
Posted on 14/05/09 12:53:09 PM |
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David Asch
Tech Support Posts: 1913 Reply  |
Re: Can anyone clarify/explain this to me?
The PNG's Interlacing is similar to JPEG's progressive option. It's mainly intended for web display, particularly slow connections as it uses algorithms to build up the image using interpolation while it's still being downloaded. It's not really relevant these days with high speed connections. The four TIFF options control the compression of the image. None is obviously no compression at all. If you do want to reduce the file size, use LZW or ZIP as they are lossless. JPEG will reduce the quality slightly, as it does in its native format. Interleaved and Per Channel are different ways the pixel information can be written to the file. It's best to leave it as Interleaved as that is the more widely used format; some programs may have problems reading Per Channel encoding. _________________ A happy-go-lucky chap, always dressed in black |
Posted on 15/05/09 01:22:25 AM |
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tooquilos
Wizard of Oz Posts: 2918 Reply |
Re: Can anyone clarify/explain this to me?
David, thank you for explaining this. It seems that the only thing I need to change, depending on situation, is the Image Compression in the TIFF options. Anna _________________ Dorothy: "there's no place like home!" |
Posted on 15/05/09 07:15:47 AM |
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Steve Caplin
Administrator Posts: 7068 Reply  |
Re: Can anyone clarify/explain this to me?
You can't use JPEG compression in a TIFF file if you want to save it with transparency or additional layers - that's the only thing to watch out for. Also, some older apps can't read TIFFs saved with ZIP compression. |
Posted on 15/05/09 10:38:52 AM |
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David Asch
Tech Support Posts: 1913 Reply |
Re: Can anyone clarify/explain this to me?
Ah yes, I forgot to point that out about JPEG compression. Generally, I'll save a TIFF uncompressed then use Zip to shrink it down afterwards, that way it's accessible to everyone. _________________ Leap and the net will appear |
Posted on 15/05/09 1:26:48 PM |
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tooquilos
Wizard of Oz Posts: 2918 Reply |
Re: Can anyone clarify/explain this to me?
Thank you for that Steve. I use .png for transparency. Its just good to know all these things. I see these options everyday and have never known what they are. _________________ Dorothy: Toto, I've a feeling we're not in Kansas anymore |