[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Epson or HP for alt-phot ... ? (some OT)

Mitch Valburg wrote:
> ...
> I've owned and used both brands of inkjet for years.

The HP DeskJet 970 has not even been out for a year.  It may be worth a
try before generalizing it with older models.

> ...  The replaceable
> heads on the HP's wear out after just a few refillings (an average of perhaps 3
> in my experience). ...

HP strongly recommends NOT to refill the ink cartridges for the 970,
they claim it could damage the printer.

So as to get this back on topic, the following progress report is given.

The DeskJet 970 does have good potential for making good negatives for
Pt/Pd and I will write up my efforts on this when ready.  Although I
greatly appreciate the work accomplished by Dan Burkholder, Dave Fokos,
and others, I am attempting a different approach.  Not better, maybe not
worse, but different.

Some of the differences follow:
No monitor calibration is needed.
Decisions are made from actual Pt/Pd prints.
The original negative is optimized for the scanner used.
Output of ink for the negative is based on the tone produced in the
print.
Levels define the maximum range of black and white (0% and 100%, not 5%
and 95%).
Curves are determined sort of backwards by adjusting the scanned
information to give a known, calibrated print value (not using a
calibration image).
The RGB scan is converted to CMYK with 0% cyan (the cyan ink is fairly
transparent and not used).

So far I have made some fairly decent negatives on HP Rapid Dry
Transparency Material and non-hardner fixed Tri-X film.

My main purpose for a digital negative is to accomplish the results of
masking I have done by analog methods.  To this end the manipulation of
various curves (highlights, shadows, and mid tones) is of prime
importance.  The greatest advantage of the use of digital is that steps
or decisions can be reversed or called back with a click.  By analog,
once something is done, one must start over to change it.

I feel that 1200 ppi should be a good enough resolution.  (I have
noticed some difference when useing 600 ppi.)
I am not yet sure of the amount of steps needed as it seems about 40%
ink is needed to get some tonality above black.  With the three colors
(MYK), I am trying to get all 256 steps to fall between 39% and 100%
with good discrimination.  Any ideas out there?

-- 
Jeffrey D. Mathias
http://home.att.net/~jeffrey.d.mathias/