Re: Digital negs-was Re:quotiing Paul Anderson
Albert Strauss (a.strauss@worldnet.att.net)
Mon, 3 Jun 1996 22:32:50 GMT
At 02:02 AM 6/3/96 +0000, you wrote:
>Hello Judy
>
>Terry wrote/amended the following on 5/30/96
>
>> > Desk top bubble jets can give negatives on A4 typing paper that produce
>better
>> > gum prints than I have seen from the strange obsessionists. Gum can be
>forgiving
>> > enough to enhance such a negative. It is one of the advantages of gum.
'Good
>> > enough for gum' is not necessarily a pejorative comment, but it often is,
>from
>> > the ignorant.
>>
>> What kind of resolution? I'm having trouble printing high-end digital
>> negatives because my style of printing on smooth paper has no forgiveness
>> -- a small amount of dot gain (which does happen) and bingo, measles.
>> Have you got one of those desk top negatives on A4 paper? Can you make a
>> copy & send it to me?
>
>It was Barnaby Cox 'wot done it' not me, but he is busy writing his
dissertation
>at the moment so he probably want see this until next week, but he did say how
>he did it on the list recently.
>
>Well I've written the dissertation so now a can add my tuppence worth to the
>debate, for details of the printer, resolution and set up see my posting from a
>couple of weeks ago Re: Inkjet negs (or something like that).
>
>I've spent the weekend playing with the printer and trying to sort out some
>problems associated with it; it all seems to be going rather well -more details
>when the problems are solved or I'm driven to distraction by them.
> When I wrote that the results were "good enough for gum" the main point was
>regarding the density range not the fundamental resolution. The printer
works at
>a screen frequency equivalent to about 150 lpi but because it produces random
>dots rather than a regular screen it is very smooth and unobtrusive.
>The resulting prints have a lack of biting sharpness which is probably due to
>the paper diffusing the lightsource, but this hides the dots so helps matters
>somewhat.
>If you would like a sample neg to play with I'd happily send one or two over.
>
>Regarding your experience of "high-end" digital negatives I'd be interested to
>know how you go about producing them, most of the stuff I've seen written about
>the subject seems to go about the process in a somewhat unecessary manner.
>
>When I get the chance I'd like to experiment with Stochastic screening
>techniques such as Agfa's CristalRaster. An English outfit are using such
>techniques to produce four colour carbon prints to much acclaim over here.
>Does anyone else have any experience with this technique?
>
>Barney.
>
Barney,
What kind of printer are you using to get 150 lpi?
In his gum book Skopick claims that you can get good results starting at a
minimum of 85 lpi. 100 - 150 lpi is better.
The average laser or bubble jet at 600 dpi, assuming a 256 grey scale
density range, cannot produce greater then 38 lpi, which is quite coarse
(well below newspaper quality). The only printer that I have found capable
of forming a 150 lpi image is a 2400 bpi imagewriter.
By the way, Dan Burkholder in his book "Making Digital Negatives" claims
that error diffusion is superior to stochastic screening.
I am interested in hearing more about your experimentation.
Al Strauss