What compression is used?



I am converting a few image files to PDF documents. When I convert a JPEG, the PDF is the same size, so is obviously using JPEG (DCT) compression for the colour image.

However, when I add a Group 4 compressed TIFF file, the PDF is 70KB, when the original TIFF was 10KB. What compression is it using for black and white images and is there any chance it could support Group 4 compression, because I will need to be able to create 50 page PDF files in this way and there is a huge difference between 500KB and 3.5MB.




Dear Chris,

Thank you for considering Aspose.

For the images that are already compressed, we use it original compression. Since you are using black-and-white TIFF image, please set the ImageInfo.IsBlackWhite to true and set CcittSubFormat to Group4. If you still can't get it work, please send one of the image and let us check it.


That worked thanks.