Re: inkjet negs?

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From: Nick Makris (nick@mcn.org)
Date: 11/05/00-02:20:49 PM Z


Mark, I was think about this thread and it occurred to me that the post
below that I made in July is relevant here. One thing that I want to add to
this is that if you are using shades of black ink (in my case 25, 50, 75 &
100% blacks) all bets are off on any curve found on the CD from Dan B's
book. It took me some time to figure out why I couldn't make it work.

Also, I have found success with Epson's Backlight Film - you must have the
correct settings for your printer. Don't recall which one you have, however
for the Epson 1520, I lie to the printer about the paper like Dan says and
print with Microweave set to "Super", Ink set to "Color", High Speed "Off"
and Print Quality set to "Superfne - 1440 dpi". As I indicate below, 360
dpi prints best - I have it on my list to try a 720 and 1440 scan. Soon
maybe???

Nick

BTW, I have an extensive collection of posts about Digital negs that I could
forward to you as attachments to a single email.

----- Original Message -----
From: "Nick Makris" <nick@mcn.org>
To: "Alt Photo" <alt-photo-process-l@usask.ca>
Sent: Tuesday, July 11, 2000 8:11 AM
Subject: Digital Pt/Pd tones continued

> Just finished running some tests with a particular image from Photoshop
> v5.02 to Epson 1520 (1440dpi). The tests included two versions of the
same
> file, one scanned at 410dpi (the most recent) and one at 360dpi - the more
> recent one and this test were done on the heels of the recent discussion
on
> tones. Please understand that my printer is equipped with a Quadtone
inkset
> with a standard black ink and with the color inks replaced with 25%, 50% &
> 75% black inks.
>
> You may recall that I discovered, now from two sources, and previously
> reported, that the Epson 1440 dpi printers don't print images with
> resolutions greater than 360dpi as well as those at 360. The problem
> extends from the idea that above 360dpi a certain amount of resampling is
> done by the printer, which causes results that are unpredictable. In this
> case, all the images I printed from the 410dpi source showed some sign of
> posterization while the 360dpi source produced no signs of posteriztion,
> except as noted below. In addition, the 410dpi file caused the print time
> to double +/-. The resampling surely has something to do with the
printer's
> processing algorithm and the coincidental association of 1440(printer
> resolution)/4(cmyk?)=360???.
>
> Some additional observations that came from the 20 8X10 images I printed
> (most printed on satin inkjet (94 brightness) paper, but some on bond for
> comparison):
> a.. The smoother the paper surface, less posterization and the better
the
> definition.
> b.. The brighter the paper brightness index the cleaner the highlights.
> c.. A simple conversion to grayscale produced posterization where the
use
> of Lab color mode did not in most cases.
> d.. The use of color images never printed as cleanly as with Lab mode -
> remember that I'm using quadtone inks.
> e.. The use of strictly black and white color did not produce an image
as
> clean as those produced with a slight sepia toning.
> f.. I NEVER EXPERIENCED ANY ON SCREEN POSTERIATION WITH ANY OF THE TEST
> IMAGES. I feel this suggests the culprit, in most posterization problems,
> is related to how the printer reacts to the input. Can't be sure of that.
> I don't pretend to fully understand why I experienced the above, but for
> what it's worth.....
>
> I have developed/refined a Photoshop "Action" that will convert any color
> image (from a point that you think it looks best) to Lab Color, delete the
> appropriate channels, apply grayscale, a sepia tone, and convert it back
to
> RGB so that it looks like a sepia toned grayscale image. BTW, I never
save
> my files after this conversion - it only takes a few seconds to complete.
I
> also have a Pt/Pd curve that I think works for both the Lightjet 5000 and
> the Epson 1520 with quadtone inks. I am happy to provide them to anyone
who
> asks off list.
>
> Also, as I have previously reported, no curve that I encountered during
the
> last year and half (since I started this digital project) works with the
> above. The curve that I developed is a very straight forward (gentle 'S')
> one that only gives the appearance of added contrast to the on screen
image
> and also to the printed output. You may be required to change it so that
> the resulting prints (negs) conform to a density and contrast compatible
> with 'YOUR' normal sensitizer. The unsuccessful curves that I tested all
> seemed destined for output to an Imagesetter which apparently responds
> differently???
>
> BTW, all the above tests/observations were done with a positive output.
> However, I have tested the conversion to a negative and the results are
> identical. The negative conversion is the last step before printing and
can
> be accomplished in the printer dialog box or on the Image menu.
>
> Caveat Emptor.
>
> Nick
>
>
>


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