Compression options

[bcgirton]

I've just been experimenting with image compression options, and would like to request additional features. I regularly create 300 MB files containing only about 70 uncompressed JPG images, with no other content. The print-on-demand service I use has a hard limit for uploads of 300 MB, so I usually shoot for just under this. In PDF-XChange Editor, the Save As Optimized gives the best compressed image quality when the compression options are set to JPEG2000 and Maximum, but some very slight artifacts are still visible, for example, around text edges. In a recent example, these settings reduced the file size from 300 MB to about 100 MB. I don't need such a large reduction in size, and would prefer to reduce the compression artifacts even further. I know there are many possible workarounds, such as pre-compressing all the images slightly in Adobe Photoshop before inserting them in the PDF, or using other software such as Adobe InDesign to generate the PDF. (Adobe Photoshop has 12 levels of JPG compression, with 12 equal to no compression, and 10 usually reducing file size by about half without usually producing dramatic artifacts.) However, this would add effort and complexity to our workflow.

Is there any possibility you might offer a more nuanced set of JPG compression options? I would be overjoyed to have 1 or 2 more Quality choices between Lossless (which has no effect at all) and Maximum (which reduces overall file size by 2/3 in the example chosen).

[Daniel - PDF-XChange]

Hello Bcgirton,

Have you changed the DPI settings for these compression options? These functions should offer a considerable degree of control over the output, for example, if all your images are at 300-400dpi, and you left the default settings in place (reduce to 150dpi for color images), a massive drop in file size and some artefacts at maximum, like you have described would be expected.

Please try increasing the DPI values for compression and see if that helps to fine tune the end file size and quality desires.

Kind regards,