TIF Options save file dialog in Photoshop CS3 provides these options:
Pixel Order
-- Interleaved (RGBRGB)
-- Per Channel (RRGGBB)

What do they mean?
Does it matter which one I choose?

p

It matters to some programs. If you print from QImage you'll want to use Interleaved.

Hello Paul,

The Interleaved order is considered to be more standard way and is recognised by all applications that accept TIFF files.

The Per Channel order allows for a bit faster writes and reads of files, as well as somewhat better compression. But it is not as widely supported by other programmes (like Qimage in the post above).

Normally, modern programmes should be able to read both versions without problem, as both are in the TIFF specification. If some programmes don't like one order or the other - this means that they are not fully compliant with TIFF specs. There's a thread here on LL discussing this with Jeff explaining this in more detail.



The meaning of the pixel order is the way colour information is written in the file:
- interleaved - the FULL colour for EACH pixel is written in RGB seqence
- per channel - the red values for ALL pixels are written, then green values for ALL pixels, then blue values for ALL pixels

Regards,
Allan

Thanks Ron and Allan for complete and readable answers.
p