[pure-silver] Re: D2 filters update
- From: "mail1" <mail1@xxxxxxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Sat, 9 Feb 2008 11:08:21 -0800
I have examined this issue of filters before the image, and in front of the
lens, and I can’t say I have noticed any difference between prints caused by
the position of the filters. The filters I used in front of the lens were
clean no smudges or scratches, and little dust on the surfaces.
I suspect this might have to do with the light that is passing through the
filter is not at a point of focus, and the property that light is a wave
form and has a tendency to distort when passing around small imperfections
in it’s path, of course this defined by the laws of diffraction that can be
studied according to the principles of quantum mechanics. While diffraction
always occurs when propagating waves encounter obstacles in their paths, its
effects are generally most pronounced for waves where the wavelength is on
the order of the size of the diffracting objects. The complex patterns
resulting from the intensity of a diffracted wave are a result of
interference between different parts of a wave that traveled to the observer
by different paths. Just think of the effect of the light traveling through
our negative. Now a really confused state! Luckily we have an enlarger lens
to organize this confusion, again defined by laws of diffraction. Now if you
have a gross scratch, or a grease smear on the filter all bets are off that
the light is going to be organized to our satisfaction but again maybe we
desire a softer focus.
I did get different responses from the different filters when running
calibration tests; this was due to the different filter lots. Otherwise the
image quality was the same.
I have noticed subtle differences between diffusion and condenser
enlargers. The dust problem is, some days more than not, a real problem and
diffusion enlargers do to some extent but not completely reduce the
appearance of dust and scratches. I did notice a big difference in the
calibration curves using filters with cold cathode verses incandescent light
sources. The cold cathode lamps produced smoother curves, otherwise the
grade number were similar. This variation in curves when matched with the
variation in the film curves is interesting in the fact there are some real
winning combinations. Some might say that none of this is really that
important when one considers the problem, is the final image an image that
captures our attention and moves our emotions?
Bye, I got to back to solving the dust problem.
Jonathan [mail1@xxxxxxxxxxxxxxxxx]
.
_____
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Mark Blackwell
Sent: Saturday, February 09, 2008 7:48 AM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: D2 filters update
Nicholas you aren't being cantankerous. We just come from different
perspectives. Not once have you gotten personal, called me a name or in any
way tried to do anything other than discuss an issue. That's an adult
disagreement, and maybe not so much a disagreement as a different
perspectives. That I respect and in no way would consider it cantankerous.
I would have another word for it. In fact I would call it a helpful debate.
Now to answer your points. First probable misconception is my enlarger is
NOT a condenser enlarger, but has a mixing chamber. That makes a lot of
difference when it comes to dust. The contrast filters I have used in the
past are those Ilford 6x6 gels. Those are nothing more than plastic. When
you project through them, you project through plastic. That has to take
some of the quality out, but I agree that the acid test is can you see the
difference. If you can't, then really what difference does it make. I know
its done by many, and maybe me too. I heard no one chime in and say don't.
I haven't tested it yet, and sooner or later I will when I have time. This
will make the enlarger usable till I sort it out.
I am going to look at taking out the filter system, but doing that is going
to leave me with a big opening that will need to be made light tight
someway. May just a small piece of something an duct tape will allow me to
remove the assembly and not guess how its put together, but know how its put
together.
Your right a new enlarger is totally out of the question for me. I don't do
enough to even come close to justifying that kind of expense. Fixing this
one is preferred to finding another garage sale special. Im used to it. I
can usually find the handles in the dark. To me its like an old pair of
shoes that can be described in one word. Comfortable. IF a day or two of
my time and $50 or so will fix it, its worth doing. If it takes more than
$100 or so, it really wouldn't.
This list has been rather quiet these days though. At least my bad days are
stirring the discussion pot a bit. grin.
"Nicholas O. Lindan" <nolindan@xxxxxxxxxxxxx> wrote:
"Mark Blackwell"
> that won't stop fading of gels.
Well, if you get Wratten gels, then yes they will fade. Rosco
filters are made to go in front of thousand watt spotlights. They
will most likely survive a 100W enlarger lamp.
As someone pointed out Rosco also sells dichroic filters
(that _don't_ fade) for $9. B&H sells genuine Omega
branded dichroics for $49 - (dichroics shatter, hence
the need for replacements).
> They will cost in all likelihood as much as a new enlarger
> with the more modern head.
A new 4x5 Chromega enlarger is $3,799.95.
> Picking up one from someone going digital shouldn't
> be that hard to do. Considering my time, it is
> probably the right thing to do.
There you are most likely right.
> Now I would disagree with you on the contrast
> filter below the lens not affecting the image
> at all.
Do you have a print with and without an under
lens filter that shows the difference???
Does anyone?
> May not be significant
If it isn't significant -- then it isn't significant,
n'est pas?
> but that gel cost a quarter or so maybe to make.
About $3.50 manufacturing cost for a 20x30" Rosco
=> you are right, 23.3 cents for a 2" x 2".
> You don't spend hundreds and maybe thousands of
> dollars for a camera lens to put a filter on the
> front that cost a quarter.
OK -- I sell it to you for $1,759.89
Now for heaven's sake, don't put a daisy - that may
only cost a nickel, in front of that thousand dollar
lens and filter and take a picture of it.
Money doesn't equal quality. The lilies of the field
spin not, and yet ...
> Moving that filter above the negative carrier
> keeps the image from being projected through
> that 25 cent filter.
Err, no. It allows all the dust on the filter
to get imaged on the print. Over the negative
filters are hell, in-between the condenser filters
are only a little bit better as the dust images
as pale blobs in an otherwise even sky. This you can
demonstrate for yourself.
> The light is modified before the image is
> created so it can't be affected.
No comment.
I'm not normally this cantankerous, but some times,
- like, oh 02:51:14.567 AM on 9 February 2008 - I am.
==
Nicholas O. Lindan
Cleveland Engineering Design, LLC
Cleveland, Ohio 44121
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