Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Comparative image quality between printed volumes and free PDFs

The resolution differences between images from the high quality in printed volumes compared with the quality in the free PDFs that a user may print out is demonstrated with images of the male lucanid stag beetle, Geodorcus helmsi (Sharp, 1881) (Coleoptera: Lucanidae) published in Fauna of New Zealand 61.

Figure 136 on page 164, displayed below at about twice the published size.

The image from the free PDF (left) gives a good overall impression of the body shape and relative proportions of parts. However, details of some stuctures are not readily visible, such as the segments of the antennae or the tarsi, or are not visible at all, such as the fine punctures on the head and pronotum and setae on the abdomen although these are visible in the image from the printed volume (right).

Image of whole specimen from free PDF (left), and printed volume (right), about 2 times published size.

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Detail of antenna and fore leg from free PDF (left), and printed volume (right), about 8 times published size.

When displayed at about 8 times published size, detail of the left antenna and fore leg from the PDF (left) is not available, whereas the detail in the printed volume (right) is available.

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Figure 442 on page 196, detail of the right antenna for the male of Geodorcus helmsi.

For line illustrations, the difference between the free PDF and the printed volume is not as marked. Curved and diagonal lines, in particular, have a jagged appearance in many instances in the free PDF (left), whereas the same lines are smooth in the printed volume (right).

Line illustration from free PDF (left) and printed volume (right), about 2 times published size.

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Detail of antennal club from figure 442; free PDF (left) and printed volume (right), about 8 times published size.

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