Quality of Printed Images

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Since it is often desirable to get a good quality print on paper directly from the browser, here are the same equations as earlier. This time the `extrascale=' option has been used with a value of 1.5. More than twice the number of pixels are available, for a cost of approximately 1.7 times the disk-space³⁵.

  

Figure: Displayed math environments with extra-scale of 1.5

$$\Phi_{l+1,m,n} = \Bigl(\Phi+h\frac{\partial\Phi}{\partial x} ... ...\frac{\partial^3\Phi}{\partial x^3} + \,\ldots\,\Bigr)_{l,m,n}$$ (5)

$$\frac{\Phi_{l+1,m,n}-2\Phi_{l,m,n}+\Phi_{l-1,m,n}}{h^{2}} + \frac{\Phi_{l,m+1,n}-2\Phi_{l,m,n}+\Phi_{l,m-1,n}}{h^{2}}$$

$$+ \frac{\Phi_{l,m,n+1}-2\Phi_{l,m,n}+\Phi_{l,m,n-1}}{h^{2}} = -I_{l,m,n}(v)$$ (6)

On-screen these images appear slightly blurred or indistinct. However there is a marked improvement in the print quality. The ``anti-aliasing'' helps on-screen; in the printed version jagged edges are indeed softened but leaving an overall fuzziness.

Here are the same equations yet again; this time with `extrascale=2.0'. Now there are 4 times the pixels at a cost of roughly 2.45 times the disk space. Compared with the previous images (having 1.5 times extra-scaling), there is little difference in the on-screen images. Printing at 300dpi shows only a marginal improvement; but at 600dpi the results are most satisfying, especially when scaled to be comparable with normal 10pt type.

  

Figure: Displayed math environments with extra-scale of 2.0

$$\Phi_{l+1,m,n} = \Bigl(\Phi+h\frac{\partial\Phi}{\partial x} ... ...\frac{\partial^3\Phi}{\partial x^3} + \,\ldots\,\Bigr)_{l,m,n}$$ (7)

$$\frac{\Phi_{l+1,m,n}-2\Phi_{l,m,n}+\Phi_{l-1,m,n}}{h^{2}} + \frac{\Phi_{l,m+1,n}-2\Phi_{l,m,n}+\Phi_{l,m-1,n}}{h^{2}}$$

$$+ \frac{\Phi_{l,m,n+1}-2\Phi_{l,m,n}+\Phi_{l,m,n-1}}{h^{2}} = -I_{l,m,n}(v)\;.$$ (8)

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Footnotes

... disk-space³⁵

This figure varies with the graphics format used, and the complexity of the actual image.