[pure-silver] Re: New color head "discoveries"
- From: "Dave Valvo" <dvalvo@xxxxxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Fri, 14 Jan 2005 15:39:45 -0800
Bob, if you use the PC filters, either Ilfords or Kodaks, they are balanced
for exposure so as one changes from -1 to 3.5 (filter label) there is no
need to change exposure. When changing to 4 and up simply increase exposure
by one stop.
But when someone uses dichroics ..there is only one M filter and one Y
filter. To go from 10M to 100M more filter is added to the light path which
reduces energy and requires more exposure. This is called a subtractive
system. Ilford made an MG 500 head enlarger that is additive. Blue and
Green light is used and by pushing PC buttons on the controller the computer
adjusts the light output to balance exposure between the two lamps so paper
exposure remains constant.
What I hear you saying is you have calibrated your subtractive enlarger so
that you always have equal exposure by balancing the amount of Y against the
amount of M required. Unfortunately M is a much denser filter and to make
this system work you will limit yourself to a small range in the lower to
center of the LER range. Then as your bulb ages you will need to
recalibrate.
Dave
----- Original Message -----
From: "Rob Champagne" <app@xxxxxxxxxxxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Thursday, January 13, 2005 10:39 AM
Subject: [pure-silver] Re: New color head "discoveries"
>
> Well no I'm not referring to log numbers at all. I've been through the=
> numbers game and I have a densitometer and can do numbers if required but
I=
> much prefer the practical evaluation method. The best way to do that in
my=
> opinion is by using the AA method of adjusting neg development based on=
> printing the 11 square patches as illustrated in the negative. I have a=
> template I cut from mountboard which fits an 8x10 piece of paper. I just=
> print my zone 0 thru 10 test negs onto a piece of paper using my
standard=
> print developer etc at the given figures for G2 Y+M on my enlarger. If
the=
> shadows aren't separated enough then I use some more film exposure. If
the=
> highlights need pulling back I reduce development. The result is that I=
> know that my negs fit exactly onto a G2 setting and any discrepancies
can=
> be adjusted with contrast control on the enlarger. There is no need for=
> number ranges. =20
> Once again, it all depends on what enlarger filtration(if any) you use to=
> calibrate your neg development. Problems may arise if you use both
graded=
> and VCpaper but thats your choice, i.e. you calibrate for one or the
other=
> with or without filtration.
> Obviously you can do your calibration to how ever many stops of range you=
> like, eg 8, 9 or 10 etc.
>
> And yes, I know AA says paper batches vary from batch to batch so he
didn't=
> like calibrating to paper, but they are going to do that regardless of
what=
> your neg dev is calibrated to, so using an arbitrary paper batch (i.e.
the=
> paper batch you have to hand) to do your calibration on, is no worse
than=
> not calibrating to an arbitrary log range which you have to first work
out=
> to know what it is anyway.
>
>
> At 13/01/2005 18:55 +0100, you wrote:
> >I assume you are talking about the log exposure range, when referring to
> >numbers from 0.6 to 1.8.
> >Well, log ER 0.6 is about grade 4.8, log ER 0.8 is grade 3.5 and log ER=
> 1.55
> >is grade 0. A log ER of 0.8 is a bit low, but otherwise, you are not all
> >that far off workable conditions.
> >
> >As Richard said, dedicated VC filters get the most contrast range from VC
> >papers, but I argue that you don=B9t need that. If I could only get grade
1=
> to
> >3.5 from my color head (I do actually get 0 to 5), I could still print
98%
> >of my negatives. Sometimes I use a VC filter 5 to burn-in some local
areas,
> >but otherwise, the extended contrast range of filters is true but
> >over-rated. And using a hard-contrast filter in addition to a color head
is
> >actually very convenient, since it avoids resetting the dials.
> >
> >I don=B9t see a real problem here.
> >
> >
> >
> >
> >
> >Regards
> >
> >
> >
> >Ralph W. Lambrecht
> >
> >
> >
> >
> >
> >
> >
> >On 1/13/05 1:39 AM, "J.R. Stewart" <jrstewart@xxxxxxxxxxxx> wrote:
> >
> >> Well, my Omega Chromega Dichro DII came in last weekend and I've begun
> >> testing. with VC papers. First VC I've printed in 20 years.
> >>=20
> >> I've been using metol glycine based Ansco130 paper developer (modified
by=
> AA
> >> and without hydroquinone).That's where I started. Problem is, the
hardest
> >> contrast I was able to get with 0Y/170M was about 0.8 on Forte
Polygrade=
> V
> >> (boy is that paper really blue!!) and about 0.6 on Kodak Polymax Fine=
> Art.
> >> The softest contrast comes in about right at 1.8 (polymax) and 1.4
> >> (polygrade).
> >>=20
> >> Glycine is a much softer developer.. is that why I'm able to get no
more
> >> than ISO ~3.5 on the VC papers... do the emulsions require stronger
> >> developers for satisfactory development? I tested my graded papers
under
> >> white light exposure, developed them in A130, and acquired the right=
> scale.
> >> I developed all the test prints at 6x factorial so I would think that=
> would
> >> be sufficient, and I was able to get max black.
> >>=20
> >> I ran an Ansco 120 test last night. The test prints look better, but=
> haven't
> >> read them yet.
> >>=20
> >> Also, I learned that both of these paper are very sensitive to the
Thomas
> >> safelite... I ran a screening test and at 5 minutes exposure I got fog=
> that
> >> appeared as Zone VI reflectance.. So, I move the safelight, unplug it,
or
> >> change papers to one less sensitive, and retest. Such is life.
> >>=20
> >> J.R. Stewart
> >> Leesburg, VA=20
> >>=20
> >>=20
> >>=
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
> =3D=3D=3D
> >>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
> =3D=3D=3D=3D=3D=3D=3D
> >> To unsubscribe from this list, go to www.freelists.org and logon to
your
> >> account (the same e-mail address and password you set-up when you=
> subscribed,)
> >> and unsubscribe from there.
> >
> >
>
>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
> =3D=3D=3D=3D=3D=3D=3D=3D=3D
> >To unsubscribe from this list, go to www.freelists.org and logon to your=
> account (the same e-mail address and password you set-up when you=
> subscribed,) and unsubscribe from there.=20
>
>
============================================================================
=================================
> To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you
subscribed,) and unsubscribe from there.
>
=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you subscribed,)
and unsubscribe from there.
Other related posts:
