[pure-silver] Re: New color head "discoveries"
- From: "Rob Champagne" <app@xxxxxxxxxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Fri, 14 Jan 2005 22:51:30 +0000
Well no I haven't calibrated my enlarger but I have checked its out of the box
calibration against what is given for my enlarger by ilford on the datasheet
which comes with a box of ilford paper.
it says for G2 use 45Y + 24M combined. This is equivalent to an ISO grade 1
filter(or ilford G1 filter). If I calibrate my neg development for normal
printing against these filter settings then I get good film speed and an
available increase in contrast from these G2 values which is greater than if I
were to calibrate my neg development against 0 filtration or Ilford G2
filtration. Hence my original question.
incidentally I have also checked all the given settings of combined Y+M for the
other grades and the given setting for G3 is damn close to a true ISO grade 2.
Therefore if I were to calibrate my negative dev to an ISO grade 2 I would only
have available 2 higher grades of paper contrast using dichroic filtration.
However, because I calibrate to the given G2 setting which actually corresponds
to an ISO G1 I get contrastier negatives which compensates(the negative scale
fits the paper) and gives me a full 3 grades of available higher contrast to
use on my Dichroic head should I need them.
This is the equivalent of calibrating to an ilford G2 filter(not my dichroic
head) and then having a further 3 grades of ilford contrast available.
In a nutshell, if you calibrate your standard dev against dichroic filtration
which corresponds to ISO grade 1 then the available increase in contrast
available to you on a dichroic head will be around 3 grades..
Whether you might actually want to do that is a purely subjective decision
based on whether you prefer longer or shorter toe and shoulder in your prints.
I do it and am happy with my prints.
I was just curious if other people did this or had observed this but since
Kodak and some other manufacturers don't seem to publish combined filtration
settings I guess other people don't use their dichroic filtration that way. The
question then becomes irrelevant to them.
At 14/01/2005 15:39 -0800, you wrote:
>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
>>
>>
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