[pure-silver] Re: New color head "discoveries"
- From: DarkroomMagic <info@xxxxxxxxxxxxxxxx>
- To: PureSilverNew <pure-silver@xxxxxxxxxxxxx>
- Date: Sat, 15 Jan 2005 17:22:51 +0100
I have calibrated my Durst enlarger for four papers to generate true ISO
grades. The filtration-settings are slightly different for all four papers,
even between Ilford MGIV RC and FB. A setting of Y40M25 creates between
grade 1.5 on the softest paper and grade 2.5 on the hardest paper.
To me, this is enough difference to calibrate the enlarger for the different
papers. Also, if I do that in the future, for a future enlarger and paper,
my current enlarging documentation will still be good.
Regards
Ralph W. Lambrecht
On 1/14/05 11:51 PM, "Rob Champagne" <app@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> 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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