Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site decwrl.UUCP
Path: utzoo!watmath!clyde!floyd!harpo!decvax!decwrl!dec-rhea!dec-mrvax!ddb
From: ddb@mrvax.DEC (DAVID DYER-BENNET MRO1-2/L14 DTN 231-4076)
Newsgroups: net.rec.photo
Subject: Color darkroom
Message-ID: <1658@decwrl.UUCP>
Date: Mon, 18-Jun-84 12:30:34 EDT
Article-I.D.: decwrl.1658
Posted: Mon Jun 18 12:30:34 1984
Date-Received: Thu, 21-Jun-84 03:21:40 EDT
Organization: DEC Engineering Network
Lines: 88

In answer to Daryl Richman's query about color processes for home darkroom
use, here are some observations based on playing with color a bit over
the last two years (and extensive B&W work over the past 15 years):

Ektaflex is pretty neat; in particular, the ability to print from both
slides and negatives with the same process (though different interneg
films) is useful.  The size print you can make is limited by the size of
the laminator you use; the default one is 8x10, there is an 11x14 available
but I think it's very expensive.  The print quality is pretty good and
the print permanence is very good (much better than ektacolor materials,
not nearly as good as dye transfer; I think somewhere around Cibachrome).

The Ektaflex materials, particularly for printing from slides, are very
expensive (on the order of $3.00 per 8x10 print made).  

Other processes to consider are:

Agfachrome-speed: This process produces prints from slides using one
processing bath plus a water wash.  I find it easier than Ektaflex to
use, and it's cheaper to get started since you don't need to buy the
laminator that Ektaflex requires.  There is no process for printing from
negatives.  Because there is no laminator, the maximum size print you can
make is controlled by your tray sizes and available materials.  I think
this stuff is available up to at least 16x20.  Materials cost about the
same as Ektaflex.  Agfachrome-speed makes provision for contrast control,
which can be very useful.

Cibachrome: The most famous print-from-slide process for home use.  I have
not used it myself, these remarks are based on information from a friend
who has used it extensively.  The processing chemistry is pretty vile,
you should make sure you have good ventilation in your darkroom.  You will
need a processing drum and motor agitator base.  A water bath of some sort,
preferably with thermostatic temp control, is a real good idea.  However,
many people make do with less.  The actual rate of production is not much
slower with Cibachrome than with Ektaflex, but you spend more of your time
actually doing things (with Ektaflex you spend 6-15 minutes waiting while
the film/paper sandwich does its magic).  Cibachrome materials cost less
than either of the first two processes.

Ektacolor: Kodaks process for prints from color negatives.  Very cheap.
This is the process used by almost all commercial laboratories for color
prints from color negatives.  It's not really much harder than Cibachrome
to use.  The paper is available in two contrast grades.

(not sure of proper name; Ektachrome, maybe?) Anyway, Kodak's process for
color prints from color slides.  Included for completeness, I have almost
no knowledge about it.

-----------------------------------------------------------------

Prints from slides versus prints from negatives:

It's easier for a beginner to make prints from slides than prints from
negatives.  That's because you can look at a slide directly and make
some judgement about the color balance, and because the slide itself provides
a reference standard to compare the prints to.

Negatives are cheaper to shoot, have more "exposure latitude" (there is no
such thing, but never mind), and provide better color rendition and
definition.

-----------------------------------------------------------------

Since you mentioned C41, another short discussion of processes:

C41 is the standard Kodak process for developing color negatives (and is
also compatible with Ilford XP1 B&W film).  It's very easy to use if you
have a processing drum and agitator base; It's possible to use without
that.  You need temperature control for the solutions before they go
into the drum.  Use a waterbath; a thermostatic control is not necessary,
particularly if you have a friend to help you process.

E6 is the standard Kodak process for developing color slides.  All the
comments about ease of use I made about C41 apply here also.  I've
participated in developing hundreds of feet of E6 film over the last
two years.

Most color negative films are C41-compatible (all the ones I can think
of at the moment).  Most color slide films are E6 compatible.  All films
I've seen that are compatible with one of these processes say so clearly
on the film cartridge, so there shouldn't be any doubt.

------------------------------------------------------------------

It's nice to see a question I have some information about.  Thanks.

			-- David Dyer-Bennet
			-- {decvax|ihnp4|allegra|qubix}!decwrl!rhea!mrvax!ddb