B&W Negs. Time delay trigger. Colour Slides
Paul Salanitri
1) When I put some negatives in the holder, and press down on the
glass, optical rainbow like swirls appear, which unfortunately
appear on the print. It is almost like it is oily, perhaps from
my handling them (I do take care though). What is an easy way
to rid this problem.
2) I have a Praktica SLR - manual everything, and would like an ultra
simple timedelay for the trigger. By simple - I mean something
simpler than this -
I have a remote trigger which I've hooked up to a string with
a 750ml wine bottle hanging of it, (everything is supported by a
tripod). I then have a higher up wine bottle with a tube between
the two - the tube being always filled with water, so that lifting
it up starts a siphon into the trigger bottle and putting it on the
ground siphons the water back for the next go.
Basically when enough water has siphoned into the trigger bottle
the trigger goes. This needs *roughly* 7 to 10 Newtons force:
i.e. 700grams to 1000 grams.
By restricting the tube by various methods, I can get a time delay
from 10-20 sec to 60-90 sec. However, a more precise method would
be useful.
3) TOUGH question: I would like to take colour slides, and develop them.
however - I don't feel like outlaying the amount necessary to PRINT
the colour slides with "CYBACHROM" (or how ever it is said)
Is it possable through some ingenous method to take and develop
colour slides, but the PRINT IN B&W?????????????
(I know that is a hard one) I've even thought about taking pictures
of the slides themselves - but a *LOT* of quality would dissappear
and I don't want that.
--
==========================================================================
Paul Salanitri sgc...@citecuc.citec.oz.au
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Jeff DelPapa
> 1) When I put some negatives in the holder, and press down on the
> glass, optical rainbow like swirls appear, which unfortunately
> appear on the print. It is almost like it is oily, perhaps from
> my handling them (I do take care though). What is an easy way
> to rid this problem.
These are newtons rings. they are caused by the light interfering with
itsef in the small irregularities between the emulsion and the glass.
(this is occaisionally usefull - it is a very accurate way if seing if
something is *really* flat). Special anti-newton glass exists, as do
glassless carriers [for the smaller sizes]. I have also heard of [but
only heard of, never actually seen] an anti-newton aresol spray.
<dp>
Ron Speirs
>
> a 750ml wine bottle hanging of it, (everything is supported by a
> tripod). I then have a higher up wine bottle with a tube between
> the two - the tube being always filled with water, so that lifting
> it up starts a siphon into the trigger bottle and putting it on the
> ground siphons the water back for the next go.
> Basically when enough water has siphoned into the trigger bottle
> the trigger goes. This needs *roughly* 7 to 10 Newtons force:
> i.e. 700grams to 1000 grams.
> By restricting the tube by various methods, I can get a time delay
> from 10-20 sec to 60-90 sec. However, a more precise method would
> be useful.
Is your name Rube Goldberg??
> 3) TOUGH question: I would like to take colour slides, and develop them.
> however - I don't feel like outlaying the amount necessary to PRINT
> the colour slides with "CYBACHROM" (or how ever it is said)
> Is it possable through some ingenous method to take and develop
> colour slides, but the PRINT IN B&W?????????????
> (I know that is a hard one) I've even thought about taking pictures
> of the slides themselves - but a *LOT* of quality would dissappear
> and I don't want that.
>
You CAN make B&W prints directly from slides; the process is very similar
to making B&W slides.
First Developer 60-90 seconds
Rinse 30 seconds
Bleach R-9 30-60 seconds
Rinse 30 seconds
Clear CB-1 30 seconds
Rinse 30 seconds
Expose to light 40 W bulb for 3 seconds at 20 cm
Second Developer 30-60 seconds
Wash Normal paper washing time
Dry
First Developer: The original literature (Kodak G-14, "Direct Positive
Photography"), specified a high contrast developer, D-88. I found it to
be too contrasty; good ol' Dektol should be a good starting point.
Rinses should be under running water, or at least two changes in the 30
seconds.
Bleach R-9 (modified):
Water 800 mL
Potassium Dichromate 9.5 g
Sodium Bisulfate 66 g
Water to make 1 L
Clear CB-1:
Sodium Sulfite 90 g
Water to make 1 L
Second Developer can be Dektol again. Or if you want a sepia toned print,
skip the light exposure and use Sulfide Redeveloper T-19 (Sodium Sulfide
20 g with water to make 1 L).
Remember that typical B&W paper is blue-sensitive and blind to red and so
the tonality might not be correct. To maintain correct color tonality,
you could use panchromatic B&W paper - Kodak Panalure or similar.
As with any positive process, the density result is opposite from
ordinarily processed paper: More exposure = lighter print, less exposure
= darker print.
> Paul Salanitri sgc...@citecuc.citec.oz.au
Ron Speirs, Evans & Sutherland Computer Corp., Salt Lake City, Utah
Barry Sherman
>I have a few questions, having just started developing and printing:
>
> 1) When I put some negatives in the holder, and press down on the
> glass, optical rainbow like swirls appear, which unfortunately
> appear on the print. It is almost like it is oily, perhaps from
> my handling them (I do take care though). What is an easy way
> to rid this problem.
Oh boy. Good luck. The problem is called "Newton's Rings" and I've been
battling it ever since I started using 4x5 negs in a glass-type negative
carrier. In fact I'm starting to think of it myself as "The Lord of the
Rings". (Hey, how's that? I both turned your stomachs with the pun and
totally dated myself, all in 5 words! Pretty good, eh, wot? :-) Except
that I'm not yet sure who's won, the rings or me.
The rings are caused when two smooth surfaces are in very close, but not
quite perfect, contact. I understand it to have something to do with
diffraction but don't really understand it. But I've lots of experience
in fighting it.
Here are options:
* Best option of all. Switch to a glassless negative carrier. This will
immediately eliminate the problem. Chances are that such a carrier will
be available somewhere for your enlarger. Or you could make your own. I
doubt that it would cost more than $50 to have a sheet metal shop punch
out a couple of pieces of aluminum to an appropriate shape. An additional
benefit is the elimination of 4 surfaces which can catch dust. (Although
when doing 35mm I've not found dust on the outer surfaces of the glass to
be a problem since the lens is so close to the negative and aperatures
large enough that DOF is minimal and the specks don't show up. I *have*
found dust on the outer surfaces of the glass to be slightly noticible when
enlarging 4x5 negs since the lens is much further away from the neg and DOF
is greater and I'm working at smaller aperatures. In fact, I'm having
trouble with blemishes in my diffusing material showing up on my enlargements
from 4x5.)
You may, however, find that you *must* use a glass-type carrier. This is
the case with me. I have 400 watts of bulbs in my head and they produce
enough heat to make the negative buckle if its not confined between two
sheets of glass. I had to have a machine shop make me a couple of metal
holders into which I fitted glass, since I can't get parts for my old
enlarger.
* Next you try "anti-newton" glass. This is glass that has a very slight
texture to it, supposedly minimizing close contact between the negative and
the glass, thus eliminating the rings. Typically it's used only for the
upper glass surface since negatives tend to curve in that direction and
that's were problems usually occur. However, Howard Bond, in a recent
article in Camera and Darkroom (or maybe Darkroom and Creative
Camera Techniques) noted that he's found that the emulsion side of TMAX
films is smooth enough to require anti-newton glass for the bottom surface
as well. I feel unconfortable about putting that textured glass between
the negative and the lens, but I certainly can't fault Howard Bond's
images for lack of sharpness.
I've not found the anti-newton glass to work 100% of the time. I've had
serious problems with rings appearing in evenly toned, mid-to-high valued
areas of a print (e.g. the sky). The worst problem is when they don't
appear on the first print of a series and then when I run off another 3
copies, they all have he rings. On one print I threw away at least 2 dozen
sheets of paper because of this. I assume this is due to the head heating
up and the negative pressing more intimately against the glass.
I bought the anti-newton glass from a company named "Focal Point" in
Glendale, Calif. Nice guy (at least on the phone). He'll cut the glass
to order and bevel he edges. I believe that the cost was $25 for a 4.5x5.5
inch piece. They're in directory assistance and they advertise in the
back of Camera and Darkroom.
* There's a spray from Technal which helps also. You spray it on the upper,
base, surface of the neg and it provides some more texture. In my
worst case I wound up spraying the stuff on *both* surfaces of the negative
*and* on the upper surface of the glass in the carrier. That finally
solved the problem. Interestingly, I could detect no degradation in image
sharpness, although this was only an 11x14 enlargement from a 4x5 neg.
Greater enlargement might have revealed a problem.
The stuff is cleaned off surfaces with the Technal negative cleaner. I
really hate to spray lacquer (that's about what it amounts to) on my
negatives but have gotten that desparate on occasion.
The spray and cleaner are available from Calumet (1-800-CALUMET).
* My best solution to date is to use spacers to prevent tight contact
between the glass and the negative. I used a micrometer to measure the
thickness of the film that I was printing (TMAX 100). Then I went around
"miking" things until I found a material that was slightly thicker. (
(In this case it was some Fuji Velvia sheet film.) I cut two strips of
the spacer material and laid them along two parallel sides of the lower
negative carrier. This prevented the glass and the negative from being
squeezed tightly together. Combined with the anti-newton glass and,
occasional use of the anti-newton spray, this seemed to solve my problem.
* Finally, I've switched to a totally different way of holding negatives.
This was not done in response to the newton ring problem.
My old setup had the entire weight of the head resting on the negative
carrier. I suspect that this not-inconsiderable weight contributed
heavily (Hey, 2 puns in one posting! I'm really on a roll!) (On a
roll? Groan. Now *that* was accidental. :-) to the problem.
Then I bought a Condit Pin Registration system. The negative carrier
works differently. The weight of the head is not transmitted to the
glass. There's a sheet of glass which rests on top of the negative but
it isn't being pressed down with all the weight of the head. This seems
to be much less ring-inducing, although I've not printed any negs with
the type of untextured mid-to-high values which really show off the
rings. I suspect that replacing the upper glass with anti-newton glass
or just using the spray will be all that's required if rings do turn
out to be a problem now.
Good luck and I hope you don't need it! Newton's rings have made my life
in the darkroom, periodically, hell. It just doesn't work to mount and mat
a photo and hang it up and say "Gee, look how good it is if you just ignore
those concentric rings all over it!"
Barry
--
|----------------------------------------------------------------------------|
| Barry Sherman, Amdahl Corp. | "Any fool can face a crisis - it's |
| b...@ruts.ccc.amdahl.com | this day-to-day living that wears you |
| | out." - Anton Chekhov |
|----------------------------------------------------------------------------|
| Amdahl, being a corporation, is a legal fiction. Therefore it is incapable|
| of holding, let alone expressing, opinions. Unfortunately, this has been |
| said of me as well. |
|----------------------------------------------------------------------------|
Tony Arnerich
> 1) When I put some negatives in the holder, and press down on the
> glass, optical rainbow like swirls appear, which unfortunately
> appear on the print. It is almost like it is oily, perhaps from
> my handling them (I do take care though). What is an easy way
> to rid this problem.
These are Newton's Rings, caused by interference effects of the
light waves bouncing back and forth in the airspace between the
film and the glass. I know of three ways to avoid them:
- Use a glassless negative carrier. This will also eliminate 4 of the
six surfaces you have to clean, so your life will become much easier.
This will also allow the negative to curl, making your life somewhat
more difficult.
- Get an "Anti-Newton" glass carrier, if one exists for your enlarger.
This works by having the glass surface on the back side be textured
enough to hold the film far enough (several millionths of an inch)
so that the patterns fade away.
- Get some of the spray powder to lightly dust the glass for the same
effect as the second solution. I don't happen to endorse either fix
#2 or #3.
> 3) TOUGH question: I would like to take colour slides, and develop them.
> however - I don't feel like outlaying the amount necessary to PRINT
> the colour slides with "CYBACHROM" (or how ever it is said)
> Is it possable through some ingenous method to take and develop
> colour slides, but the PRINT IN B&W?????????????
Tough Answer: If you want B&W prints as the final result, why shoot
color positives? You're making a lot of work for yourself. I'm not sure
that I've ever seen any good way to develop B&W prints as positives, plus
you get unpredictable results (especially with variable-contrast paper -
which has two emulsions which are differentiated by contrast and color
sensitivity) when printing full-color originals onto B&W paper.
> (I know that is a hard one) I've even thought about taking pictures
> of the slides themselves - but a *LOT* of quality would dissappear
> and I don't want that.
By far the highest quality route is to shoot B&W copies of the slides.
Degradation? None that you will notice if you do things right. Make a
sheet film internegative with B&W copy film (consult Kodak brochures),
then you can even contact print the neg onto B&W paper & you're done.
Next best is to use a DECENT slide copy set up (bellows, macro or
enlarging lens) to make 35mm internegs. You have to use a film with
a long, straight curve, developed for slightly low contrast: try
TMAX 100 with times about 10% less than on the sheet. This will make
sure that you don't lose tone response in the shadows or the highlights.
But really, just do the original shooting in B&W film.