I've realised I'm confused about what's in a TIF file, and maybe my software
is confused too.

I have some images taken with PView 2.0 and a 416 camera in high resolution
mode (512x768). I saved the images from pview as TIF files. The image files
on disk are 791,121 bytes, which corresponds to 16 bits per pixel with a
little overhead. However when I open one of these files with Corel Photo
Paint it says it's a Grayscale 8 bit uncompressed file. If I save the file
out with Corel unchanged to a TIF file the resulting file is 393,751 bytes,
corresponding to 8 bits per pixel. The 416 is a 16 bit camera, did I do
something wrong when I saved the image with PView which caused it to become
an 8 bit/pixel image padded out to 16 bits per pixel? I didn't do any
processing other than to subtract the dark frame.

Secondly, I got a copy of Maxim DL, the Win95 version of Hidden Image. The
old HI program used to read the TIF files from PView 2.0 no problem. Maxim
DL reads the file, and displays a 512x768 window, but the image is messed
up. It seems to have just the left half of the image, it appears somewhat
squished in the vertical direction, and the half which is displayed isn't
correct (an image of jupiter for example displays a bright egg shape, but no
amount of screen stretching makes it look right with the cloud bands etc.)
The same image looks pretty good when I open it with Corel with no
adjustment needed. In the Maxim DL file open dialog the file details are
768x512, and a pixel width of 1.#IO and height 0.000. These look like
garbage numbers to me.

Finally, if I go back to that copy of image which I saved out with Corel,
and load that into Maxim DL, it reports a size of 768x512, and a pixel
height and width of 796.494 (what are the units for these numbers?). And the
image of jupiter looks fine!

So, just reading in the file and saving it out with Corel makes it into a
form which Maxim DL can read correctly. Why is this?

And what do I need to do to keep my images 16 bit with PView 2.0?

I think a long time back there was something on this list about an incorrect
TIFF implementation in PView 2.0, but I can't find it in the archives.

Thanks,
Anthony

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