What's the difference between "Small File" and "Hi Quality?"

[kawika]

Hello,

What specifically is different if one chooses "Small File" or "High Quality" when generating a PDF with doPDF?
Different resolution? Lossy compression? If so, how much and what type? Other?

From a Word document (220 pages, about 100 Grayscale images, each one 4.75x6in @300ppi) I generated one of each version of PDF.

The High Quality is 107mb; the Smaller File is 84mb.

With the same Word document, with most (70%) of the images in color, High Quality was 250mb while the Small version was only 37mb. Hard to understand how this works.

Thanks in advance for any information.

[kawika]

BTW I am aware of this info from an earlier post on another thread:
Normal ZIP compression for the High quality images filter
High JPEG compression for the Small file filter

But I am trying to understand how a file printed as "Small" with color images ends up so much smaller than a file with the same images in Grayscale, while the "High Quality" color PDF is so much larger.

I would add this to my OP but can't find a way to do so.

[Claudiu (Softland)]

Have you tried optimizing the word document for printing first? You might have images that are actually saved in the word doc in larger sizes but only used cropped and that could cause the issue.