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Are your high-compression pdfs actually usable?

29 January 2024

Until very recently, size was everything. To save money on cloud storage, PDFs from scanners had to be as small as possible. High compression, or compact pdfs processing was set to squeeze them as small as possible. But compression usually has an impact on image quality, and it came as a shock to some people that the pdf they fished out of their archive was actually so small it was no use at all: the signatures were pixellated beyond recognition, the graphs’ colours were indistinguishable and all the pictures had turned into patchworks of small, coloured squares.

With a little fine tuning of the algorithms, the output PDFs may be just slightly bigger, but the images remain usable. Inside the program for compact PDF, it’s a bit like when you save a picture as a jpeg, and you get to pick a number between 1 and 100 for file size versus quality. But not all the scanner and multifunction-printer manufacturers have got the balance right yet.

Here at DataMaster Lab, we spend days looking at this image-quality stuff in detail, so you don’t have to. We look at the impact of the high-compression button on images, colours, fine lines, and different aspects of image quality, particularly at the edges. We measure how good the OCR is too.

The upshot of all our work is that DataMaster Lab can publish a table of all the best filesize/quality ratios for all the machines on the market. These machines scan papers to make very small pdf files which are still usable in a legal or commercial context.

Looking only at filesize/quality scores, two manufacturers stand out. This is because their imaging equipment is of high quality, and because the scanner software that goes with them is top notch too.

1	Epson DS-730N
2	Epson DS-780N
3	Epson DS-360W
4	Ricoh fi-8190, fi-8170, fi-8150
5	Epson DS-32000, DS-30000
6	Epson DS-790WN
7	Epson ES-C380W
8	Canon DR-G2140
9	Ricoh fi-800R
10	Epson DS-C330

There is more to evaluating scanners than just looking at their file sizes. We look at how easy they are to use, how versatile they are, how they handle paper originals and how productive they are, including how long they take to actually process the pdf and put it in the desired location. Our awards, certificates and radar charts are based on wide evaluations reflecting real usage. 


*  Single-function scanners tested by DataMaster Lab since 2020.
Brands tested include Epson, Canon, Brother, HP, Kodak, and Fujitsu PFU which is now part of Ricoh.
Tests involved scans of test documents in grey and in colour at 200 and 300 dpi. Other tests are also carried out when DataMaster Lab evaluates a scanner and its management software.