Carl Fransman (email@example.com)
Thu, 01 Apr 1999 11:36:56 +0100
Hi Adam and Dan,
First I'd like to set something straight: PS3 does not change the rules
for us, it's still a 256 graylevel language. What they do is (through
ideom recognition) recignize some commands such as making a blend and
replace that to have an apparent 4096 graylevels, but just in these ares.
I kinda know about screens because we image films at 10160 dpi / 600 lpi
daily - I will have to disappoint you since we don't do that as an
external service. The problem with very fine screens - and why service
bureaus aren't jumping to image them for you - is the dificulty to get
consistent output. To give you an idea: we had our screen custom
developed to get the stability we required.
If you image your films at a lower than optimal resolution such as Dan's
example for Lenswork and you really need all the graylevels, there's a
workaround. Offset printers do it all the time: multiple printing. Many
photographers apply split-printing in the darkroom but so few alt-people
do it (apart from gumprinters). You could go for multiple exposure or
even multiple coating and exposure.
The streaks in your film can have several reasons: one is dust in the
imagesetter (common, but usually denied by the service bureau) which
leaves a white line on the film (often more than one pixel wide), another
is what's called 'missing scanline' - this is an electronics problem and
is usually intermittent and third there's scratches from the developer
(mostly caused by cristals in the machine due to fumes of the chemicals -
many bureaus leave their developing machine closed at night, but you
should open the covers when the machine is turned down).
Stochastic screens are nice compared to lowres screens (133-175) but
nothing beats a really fine screen for resolution and smooth tone
reproduction. You should also take into account the paper on which you're
working - no need to go finer than the paper can show...
One more remark: when using digital negs, don't use the optical
lightbanks usually described in manuals. Only a point lightsource will do
- preferably a vacuum one. You can find them secondhand at graphic arts
dealers or you can make a deal with a local printshop - they all have one
and are usually amazed at you bringing 'selfmade photopaper'.
Hope this helps you all a little
Printing & Lithography
tel +32 89 73 18 70
fax +32 89 73 18 30
This archive was generated by hypermail 2.0b3 on Thu Oct 28 1999 - 21:39:29