On Sat, 15 Jul 2006 16:18:16 -0400, "GAM" <q> declaimed the following in
soc.genealogy.computing:
I have printed the PDF chart and scanned it using a flat bed scanner
outputting it in JPEG which leads to less than optimum results. I have also
1) scanned at what resolution?
2) if you can, avoid going through JPEG format.
1 For a line drawing in primary colors the scan should be at 1:1 with
the output device resolution (or some good compromise thereof). The
reasoning is that the printer can, say, put out precise fine lines at
600/720/1200/1440 (depending on model) DPI, so a scan at that resolution
(I'd pick 600/720 -- going higher is overkill) will reproduce with close
to the original sharpness. Scanning at 150/300 DPI will result in each
cell (dot) having a chance of being a mix of ink and paper -- said mix
then registers as some value of grey, and then when you print, the
printer has to use an array of black/white dots to fake the grey.
Photos are used at a resolution of 300 because the printer hardware
doesn't have the resolution to support higher (note: I'm talking 4-color
industrial printing here -- newer 6+ color photo printers have more
flexibility). Using just pure B and W, and the common 256 levels of
discernable grey, requires the printer to use a 16x16 matrix. This is
the equivalent of the half-tone cell. Standard printing uses and image
(in pixels per inch) of 2-times the line screen (half-tone cells in
"lines per inch"). A 300PPI image implies a 150LPI production. I you
need 16 printer dots to make a single "line", you are looking at a
printer that can produce 2400 dots per inch
2 JPEG is a format designed to compress photographs (Joint
Photographics Expert Group). The technique attempts to maintain color
space at the expense of details. One black dot in the middle of a white
area will come out as a sort of speckled freckle, as the equation terms
that controlled the sharp transition from white to black have been
removed -- you instead have an equation that goes white to black through
"bounces" of intermediate greys.
If your scanner can save in TIFF, you might as well use that
format... Heck... use it, or some other uncompressed format (note: GIF
is also a compressed format -- it keeps detail by limiting the color
space to 256 distinct colors) for all work. ONLY go to JPEG for a COPY
to be transmitted to someone for review. Even for photos it is best to
do all editing in TIFF or other, save the TIFF, then convert to JPEG for
routine viewing.
tried using the screen capture facility in Photo Impression which leads to
readable but again less than satisfactory results.
No surprise -- again you are looking at a printout that might have
600DPI resolution, vs a screen that is <100DPI (To show a 600DPI
printout of a 8.5x11 page at full resolution requires a monitor window
of 5100x6600 pixels -- my high-res monitor could only show 1/4 of the
detail).
Would like to hear of experience of others how they have approached this
problem, especially if they have had postive results with any low-cost
software.
No help here... My "low-cost" software was Photoshop (3) LE, over a
decade ago... and I eventually paid the $250 to upgrade the LE to PS4
full, and have since made four additional upgrades (at $150 each)
through v5, 5.5, 7, and now Photoshop CS.
I mention this as Photoshop, at least since 5.5 if not earlier, and
Illustrator of the same time period, do have the ability to load (and
save) PDF pages. You could load that PDF chart and save it as some other
format.
--
bieber.genealogy Dennis Lee Bieber
HTTP://home.earthlink.net/~bieber.genealogy/
