Thread: Heathkit HW-101
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Old January 2nd 05, 05:54 PM
Antonio I0JX
 
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Chuck,

jpg is perfect for images and photo, but is not good when there are =
sharp black / while transitions as it occurs for circuit diagrams and =
text in general.With jpg, unless you reduce the compression level a lot, =
you will typically see small "dots" scattered around the lines =
representing the circuit wires. And wires do not appear "solid" any =
more. So, diagrams do not come out clean.

For schematic diagrams quality is the priority, not file size. Lossless =
compression (gif, png) is the only way to get a good diagram.

If you have time try and download the "improved" HW-101 schematic =
diagram from BAMA (or much better its mirror site =
http://bama.edebris.com/manuals/), you can judge yourself whether a =
technican can work comfortably with that.

73

Tony, I0JX


"Chuck Harris" ha scritto nel messaggio =
...
Antonio I0JX wrote:
I had also printed the "improved" diagram, but, although it is =

better than the other one, there still are many
details which cannot be read, and the "good" part is anyway =

fatigating to read.
=20
People keep compressing schematic diagrams with jpg or worse djvu, =

that are unsuitable for diagrams or text. So, a
great part of the BAMA schematics are poor.
=20
The only way to obtain good diagrams is to use lossless compression, =

like gif. People seems to be generally unaware
that, with diagrams, gif produces a smaller file than jpg. For =

instance, converting a bit-map diagram of 1,137 kB, I
obtained 42 kB with jpg and 13kB with gif.

=20
You can't make a general statement like that about jpg. When you make
a jpg file, you are allowed several "tweak" options that change how
much compression, and how much degradation is allowed. I can quite
easily produce a jpg that is much smaller than any gif, and has =

similar
level of quality. Most folks just accept the default parameters, =

which
are set for a reasonable quality color image.
=20
-Chuck Harris