dplatt@coherent.com (Dave Platt) (11/03/88)
I spent about an hour this morning at a local HP dealer, playing with a
printing setup that included a Mac Plus, an HP DeskJet printer, and the
new "Printer Interface III" printer-driver from DataPak Software Inc. of
Sherman Oaks, CA. I spoke to a DataPak tech-support representative this
afternoon, reported my findings, and discussed the driver's behavior.
I can't claim to have run any scientific tests, and didn't take accurate
timings at all. However, my initial notes and impressions may be of use
to people who are looking to connect a DeskJet to a Mac. The following
notes are in no particular order.
Initial impression: the driver is _not_ vaporware. It exists, and it
works... quite well in most areas, with a few rough spots here and
there. Performance appears quite acceptable, given the basic character
of the DeskJet and its interface (19.2 kbit/second serial).
Compatibility was good but not perfect: three applications worked
perfectly, one bombed, and I've been advised of two others with which
this driver is known to be incompatible.
Feature summary: the driver supports several different print densities
and styles. There are four density selections:
- "Text only, no graphics". This is similar, in effect, to an
ImageWriter's "draft" mode.
- "Draft graphics". This provides 75 dot/inch graphics output, and
displays Mac screen-fonts at 75 DPI.
- "Normal graphics". This provides 150 dot/inch graphics output.
- "Best graphics"... 300 DPI graphics.
In the "best" graphics mode (and, I infer, in the "normal" mode as
well), the driver will use and scale down "oversized" copies of the Mac
screen fonts (if available). For example, if you print Geneva 12 text
in "best" mode, the driver will rescale a Geneva 24 font to the 12-point
size and will print it at 300 DPI. The resulting output looks
substantially better than the "draft graphics" 75 DPI text; it takes
somewhat longer to print.
One big strength of the DataPak driver is its ability to use HP-supplied
fonts. The DeskJet comes with 12-point Courier built-in. Font
cartridges are available with Courier italic, TmsRmn (HP's version of
Times), Helv (HP's Helvetica clone), and a number of others. Most of
these cartridges supply a full international character set for one or
two point sizes of a specific font. The printer can generate boldface
and expanded versions of all fonts, and can do single and double
underlining, and superscript/subscript.
[These font cartridges are rather pricey... $125 list, each. The
cartridges that support the full ISO character set generally have room
for only one or two point-sizes each; to get all of the sizes of TmsRmn
or Helv, you must buy two cartridges. A better bargain, I think, is
the pair of cartridges that supply TmsRmn and Helv in 4 different point
sizes each (14, 12, 10, and 8, with 7/6/5/4-point scaled-down versions
also being available). These multi-point TmsRmn/Helv cartridges
support only the ASCII character set, rather than the full ISO
international character sets... but that's probably no loss for most
users.
A slightly different version of the DataPak driver is needed to use the
ASCII-only cartridges, though... the printer requires a different
escape sequence to activate these cartridges. This modified driver is
available from DataPak, or through their dealers, for the same price as
the standard driver; they'll provide it free to owners of the standard
driver.]
If you have selected the "Use HP fonts" check-box in the Print dialog,
the driver software will instruct the printer to access the font
cartridge(s) when printing Courier, Times, or Helvetica text. If the
correct font is available, it will be used; if not, the printer applies
its own built-in heuristic to choose the "best match" available in the
cartridge(s) that are actually installed.
[Unfortunately, DataPak says that there's no way for the Mac to query
the printer and find out which fonts are actually available... this
query-feature is available only over the printer's Centronics-
compatible parallel interface and can't be used via the serial port.
So, the driver can't use the font cartridge for Times and the Mac's
screen fonts for Helvetica. If you print a document containing both
Times and Helvetica, and have only one of these fonts installed in the
printer, then the printer will substitute one of the available fonts
when you try to use the unavailable font. Something similar occurs if
you use a point-size that your cartridge doesn't support.
It'd be very nice if the driver would permit the user to specify (in a
Page Setup options dialog) precisely which font cartridges were
available. The driver could then make more-intelligent decisions about
when to use the HP fonts, and when to use the Mac's disk-resident
fonts. This would be a nice feature for a future version of the
driver.
Special Mac characters (e.g. the "..." character generated by
option-semicolon) will not be displayed properly if an HP font
cartridge is being used; to display these characters, you must either
enter them in a Mac-only font (e.g. Geneva or Chicago), or disable the
HP-font feature and accept much lower printer speed.]
By using the font-cartridge, and sending 8-bit ASCII/ISO characters, the
driver cuts _way_ down on the number of bytes that must be crammed
across the 19.2 kbit/second serial link, and relieves the Mac of the
need to build a bitmap image. If the font cartridges are not installed,
or if you've disabled use of the HP fonts, the driver must construct a
page-image bitmap (at up to 300 bits/inch) and transmit it... a slower
process. In my admittedly unscientific and uncontrolled tests,
disabling the HP-font feature (or using a Mac-only font such as Geneva)
reduced printer throughput anywhere between 20% (in "draft graphics"
mode) to 75% (in "best graphics" mode).
The spacing characteristics of the HP-supplied fonts are slightly
different than those of the corresponding Apple-supplied screen fonts.
If you're printing left-and-right-justified text, DataPak recommends
that you select the "Precision placement" option, which will ensure that
each letter is printed at exactly the correct location on the page. If
you don't select this option, text will be printed using the HP font
spacing characteristics, and the right end of each line may not line up
as you'd expect. If you ask for a point-size that isn't available, and
the printer chooses a larger point size, then your text may run off the
right margin unless you request precision placement.
Left-justified text seems to look just fine even with the precision-
placement option turned off, as long as the family and size of the font
being printed matches one that's in the printer cartridge. The printer
may run a bit faster if the precision-placement option isn't used.
I was quite pleased to note that the driver was able to mix HP fonts,
Mac screen fonts, and QuickDraw graphics within a single page. I
printed a MacDraw document (a small street map) in "normal graphics"
mode. The driver used the Mac screen fonts when displaying text in
Geneva, but switched to the installed "Helv" font cartridge to display
Helvetica text, and drew lines of various thicknesses at 150 DPI.
The driver's idea of a "standard" printed page's margins appears to be
[nearly?] identical to that of the LaserWriter's, or of the
ImageWriter's in "Tall adjusted" mode. Little or no reformatting should
be needed when switching between an Apple printer-driver and the DataPak
DeskJet driver.
Printing speed was acceptable, although not laser-swift. The fastest
output took place when I printed a page of Courier text using the "text
only, no graphics" mode, the built-in HP Courier font, and the printer's
"Draft mode" switch [which suppresses every other bit-column, printing
with a 150 dot/inch horizontal density]. A page full of text printed in
roughly 30 seconds. The slowest printing took place when I requested
"Best graphics" printing of a heavily-filled page of Geneva text and
bitmap graphics; this page took several minutes to print.
The driver does use the DeskJet's serial-data-compression feature. When
I printed a large graphic containing lots of black-space (a Mandelbrot
set image), the printer zipped right across the image even when printing
in the 300 DPI "best" mode.
Graphics printing in "normal" and "best" mode is quite good; the driver
prints QuickDraw graphics at 150 or 300 DPI, respectively. I ran an
"acid test" that consisted of a bitmap image that I had captured on a
Mac SE, and then "shrunk down" about 60% using MacDraw. In "draft
graphics" mode, the printed image was effectively identical to what I
saw on the screen (much of the fine detail had been "squeezed out"). In
"best graphics" mode, the driver used the full 300 DPI resolution of the
printer, and displayed far more detail than was visible on the screen.
The image looked as good as if it had been displayed on a LaserWriter...
better in some respects, because the DeskJet doesn't share the
LaserWriter's unfortunate tendency to streak solid-black areas.
The driver does not support "bitmap smoothing", though... screen-
resolution bitmap graphics (MacPaint images, for example) and screen
dumps look just as jagged as they do on the ImageWriter.
The driver doesn't yet support the command-shift-4 "print screen"
feature; this will probably be added in a new version, scheduled to be
released sometime around the end of the year. I was able to use
command-shift-3 to dump the screen to a MacPaint file and then print the
image using MacPaint; it took about a minute to print, and looked just
fine.
I tested the driver using WriteNow, MacWrite, MacDraw, and MacPaint.
WriteNow seemed to work flawlessly; I had no problems whatsoever, and
the store's sales-guy said that he'd had similar results. MacWrite,
however, bombed when I tried to print; I was unable to get it to work at
all. MacDraw worked quite well, although the "size reduction" option
didn't work the way I expected it to. MacPaint worked perfectly.
When I printed a page full of Geneva 9-point text in "best" mode, some
extraneous marks appeared at the left side of some of the lines of text.
DataPak's tech-support guy said that this may indicate that the printer
and Mac aren't configured for the correct handshaking protocol ("CTS"
flow control should be used).
The driver does not support "landscape" mode at all, even for pure
graphics. Full landscape mode (including access to HP's landscape-mode
font cartridge) will probably appear in the next version.
It's possible to request a size-reduction in the "Print..." dialog box.
This reduces the size of the image printed on each page, but (unlike the
reduction feature in the LaserWriter's Page Setup dialog) it does not
reduce the number of pages generated. DataPak may support the
LaserWriter-style reduction in a future release, if they can do it
without making the driver so large that it won't run on a 128k Mac.
As I mentioned, MacWrite bombed when I tried to print. DataPak is aware
of this problem, and is working on a fix. Their driver is known to be
incompatible with Hypercard (which apparently includes hard-coded tests
for the ImageWriter and the LaserWriter) and with Microsoft Excel (which
apparently bypasses some of QuickDraw and does some "DOS-style" printing
stuff internally). DataPak is attempting to remedy these
incompatibilities.
[One warning re future compatibility: Apple has made it clear that the
current (largely undocumented) printer-driver interface _will_ change
at some point in the future. At that time, all existing third-party
printer drivers will very probably "break"; they'll be incompatible
with the new version of Apple's system software until they're rewritten
to comply with the new interface rules (which, one hopes, will
_finally_ be documented!). If you buy any third-party printer driver,
resign yourself to the fact that you won't always be able to upgrade to
Apple's latest&greatest System software when it hits the street.]
Concerning the printer itself: the DeskJet is _not_ a "cheap LaserJet"
(or a "cheap LaserWriter"), and shouldn't be thought of as such. At its
best (draft-quality Courier 12-point text), the DeskJet runs at only
about 1/4 the speed of the LaserJet. When printing complex images, or
pages full of high-quality Mac text, the DeskJet can require several
minutes to complete a page. Neither the DeskJet nor the driver
understand PostScript; you won't be able to run Adobe Illustrator and
expect PostScript-quality results. If you buy a DeskJet and expect it
to behave like a laser-printer, you'll probably be disappointed.
The DeskJet is, however, a serious potential competitor in the general
market niche filled by 24-pin dot-matrix printers. Its output quality
is at least equal to, and is probably better than most near-letter-
quality dot matrix printers such as the ImageWriter LQ. It prints at
roughly the same speed as the ImageWriter LQ, and is _FAR_ quieter (a
faint "whirr/click" rather than a tooth-aching scream). The printer is
roughly twice as expensive as an ImageWriter II, and it's capable of
vastly-superior output.
The DeskJet could also compete, in many situations, with the LaserWriter
SC... its output is of comparable quality, and it's much less expensive
to purchase. The LW SC really requires that the Mac have a good-sized
hard disk, as one must install 4x-oversized fonts in order to receive
letter-quality output. The DeskJet, coupled with this driver, could
produce similar-quality output from a floppy-only Mac, and can also make
use of 4x-oversize fonts if you happen to have them installed on a hard
disk. Of course, the LaserWriter SC can be upgraded to a PostScript
printer by swapping boards; that's not true of the DeskJet.
To sum it all up... this driver appears to be a very credible effort.
In the tests I ran, it did a decent (and sometimes excellent) job of
printing Mac application output on the DeskJet. It lacks a few
capabilities yet (landscape mode, screen dump, and LaserWriter-style
image reduction) and isn't compatible with all applications... but for
many users it could serve very well. The DeskJet seems to be selling
for $700-$750 around here; toss in $125 for the driver, and another $125
for a font cartridge, and you could have a near-laser-quality personal
printer for under $1000.
Based on my few experiments this morning, I'd strongly recommend buying
at least one HP font cartridge (either TmsRmn or Helv) for use with this
driver, as the printer runs substantially faster when using the HP
fonts.
Nondisclaimer: I have no relationship with HP or DataPak except as a
possible customer. Your mileage may vary. Opinions expressed herein
are my own, do not necessarily represent those of anyone else, and are
void where prohibited or taxed. Any errors or misstatements of fact are
probably my fault; please don't throw rocks.pv9y@vax5.CIT.CORNELL.EDU (11/09/88)
Has anyone done this kind of testing on the Grappler LS from Orange Micro? It seems to be about the same price, but does everything in hardware so it won't have problems when Apple upgrades to new drivers. I'm interested in a DeskJet, but can't tell which interface is better. Any suggestions? Thanks - Adam pv9y@vax5.cit.cornell.edu