Converting JPEG to TIF results in very large files

[lhbol1]

Hi,

I have been an nConvert user for many years and it's a great app, thanks!

I am trying to find a way of converting lots of documents scanned as single page JPG files into multi page TIF files without ending up with huge files. I can get the conversion to work fine but the best TIF compression I can get, whilst still retaining a good quality document, is around 6 times the size of the original JPG files.

The best results I get are using LZW (-c 2) but this gives me a 60MB TIF (124 pages) in comparison to the 9MB total size of the individual JPG files. I have tried reducing the dpi but this has little impact as the images are already only 150dpi. Using the -binary options result in much lower sizes but parts of the document become almost illegible and the overall quality is very poor.

Does anyone have any advice on how I can get these sizes down as with 1.2 million JPG files the resulting size increase with be huge?

Hoping someone can help.

Thanks

Ben

[xnview]

Do you have tried with JPEG compression?

[lhbol1]

Hi Pierre,

Thank you for the reply.

I have tried using the -c 8 option is this is what you mean:

C:\nconvert\nconvert -out tiff -o C:\nconvert\jpgtest.tif -multi -c 8 c:\nconvert\temp\*.jpg

This results in a much smaller file size than -c 2 but the image cannot be opened by any of the 5 tif viewers I have on my machine. A couple of the viewers report that the image is "damaged or corrupt".

I think this may be decause the -c 8 option is 24/32 bit dependent and the original JPG files only have a Bit Depth of 8. I tried using the -32bits option:

C:\nconvert\nconvert -out tiff -o C:\nconvert\jpgtest.tif -multi -32bits -c 8 c:\nconvert\temp\*.jpg

This allowed me to view the resulting tif but the file size was 1Gb!

Do you have any other ideas?

Many Thanks

Ben

[xnview]

Is it possible to send 2 original files to test?

[lhbol1]

Hi Pierre,

Not sure how to send via Forum so have emailed to webmaster. Hope this is ok(?)

Thanks

Ben