Photodocumentation

Nigel Eastmond nce at rri.sari.ac.uk
Tue Nov 8 04:14:09 EST 1994


: Obviously the computer and printer cost the most, so if you have a
: computer which accepts a full-size card, you don't need to buy one.  We
: opted to go with the 600dpi laser printer as opposed to a thermal printer
: because we could use it for more purposes.  600dpi is really necessary as
: the resolution is not nearly good enough on a 300dpi printer.

: If I had to do it all over again, I would have bought the LaserWriter Pro
: 630 for an output device.  It has better Photograde (gray scale)
: technology and an Ethernet connection too.

: re. the other questions you asked...
: Output Quality:      Not publication grade, but close to it. 
: Maintainance cost:   Paper and ink for printer


: Good luck,

: Viraj

: -- 
: Viraj Master
: Dept. of Organismal Biology and Anatomy
: University of Chicago


About this publication quality business.  What is publication quality?
The reason I ask this is that there are a number of digital capturing
systems currently available and you have to accept that what you have
is not a film.  Why not totally embrace the new technology and ditch
film entirely?  Those who have digital systems, why not try submitting 
things to a journal?  We have submitted 300 dpi ink-jet print-outs of
300 dpi transmisive scans with no trouble at all.

Journals have to realize that there is an exponentially increasing number
of gel films produced every day and consequently, we have "out-grown"
conventional photographic film.  We need digital storage and therefore
need cost-effective reproduction.  ie. NO DYE SUBLIMATION printing!!

What is interesting is that many of the resolution problems encountered
are as much to do with the ability of printers to simulate shades of grey.
All ink jet and laser printers do this by creating a scatter or moire pattern
of black dots which does not always give an even transition from one shade
of grey to another.  No printer actually has 256 different shades of grey 
ink!  So the solution is this:  Convert the scan to pseudocolour using
NIH Image.  This replaces the 256 shades of grey with 256 colours from purple
to red.  When this is printed, a colour ink-jet printer can use four 
ink cartridges to to mix dot patterns and create the correct colour.  The
net result is a photograde colour printout with the added bonus of enhanced
discernability of levels of molecular detection by eye.  This latter effect
is due to the fact that the eye can more readily discern changes in colour
than changes in grey.

So pseudocolouring is not just a toy and not just for the front cover of 
Nature.  But here is the next problem:  some journals have problems or
special requirements for colour printing.  This is repidly becoming a thing
of the past as some British journals now find it equally easy to print
in b/w and colour.

So there yoy have it.  Be brave.  Submit you digital images and see what 
happens.  Also, if anyone from a journal is reading this, we would appreciate
your input.

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| Nigel C. Eastmond             |   Email nce at rri.sari.ac.uk    |
| Rowett Research Institute     |   Tel   +44 244 712751        |
| Aberdeen                      |   Fax   +44 244 715349        |
| Scotland                      |                               |
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