What's the secret? eyes adjustment to dark

davidkachel · Dec 29, 2009

archer said:
Dear Ralph and David;
...
David, I want to thank you for your work in the development of SLIMT and for the many articles you contributed to DCCT over the years I enjoyed all of them and found them very useful.
Denise Libby

Thank you for you kind words.

Though I plan no more contributions to the technical side of photography, shortly I hope to have an effect on the more practical side, helping fine art photographers to more easily make a living.

dancqu · Dec 29, 2009

Some Of It's Working

RalphLambrecht said:
I see the technique employs bleaching with ferri!

The method is not the least bit complicated. Expose
the paper, bleach it in an EXTREMELY dilute potassium
ferricyanide solution then develop. Nothing to it really.
Processing single tray as I do, no additional space is
needed. The bleach is a one-shot.

Exposures must be increased. Dilutions vary from
paper to paper. For a set time bleach dilutions vary
according to the results desired. The method has some
similarity to Lith printing. In this case the balancing of
exposure and bleach must be correct.

I stand corrected. As David has mentioned the paper
grade is not changed. In effect exposure in otherwise
overly dense print areas is disproportionally reduced
by the bleaching of the latent image. It might be
considered as an increase in density of the
negative's thin areas. Dan

RalphLambrecht · Dec 30, 2009

dancqu said:
The method is not the least bit complicated. Expose
the paper, bleach it in an EXTREMELY dilute potassium
ferricyanide solution then develop. Nothing to it really.
Processing single tray as I do, no additional space is
needed. The bleach is a one-shot.

Exposures must be increased. Dilutions vary from
paper to paper. For a set time bleach dilutions vary
according to the results desired. The method has some
similarity to Lith printing. In this case the balancing of
exposure and bleach must be correct.

I stand corrected. As David has mentioned the paper
grade is not changed. In effect exposure in otherwise
overly dense print areas is disproportionally reduced
by the bleaching of the latent image. It might be
considered as an increase in density of the
negative's thin areas. Dan

Dan

How does it deal with local contrast requirements? In other words, how do I increase the contrast in the sky without affecting the entire print?

dancqu · Dec 30, 2009

Local vs Global?

RalphLambrecht said:
How does it deal with local contrast requirements?
In other words, how do I increase the contrast in the
sky without affecting the entire print?

Assuming the sky area of little density I'd start with
a high contrast graded paper. Were I using a VC paper
I'd expose using a high contrast filter. Follow with a bleach.
Off hand that is the only method which comes to mind.
The bleach will effectively reduce the exposure and
do the more so as areas of greater exposure
are encountered.

Local contrast? The bleach acts most aggressively
in areas of greatest exposure. Is that not local
contrast control? Dan

RalphLambrecht · Dec 30, 2009

dancqu said:
Assuming the sky area of little density I'd start with
a high contrast graded paper. Were I using a VC paper
I'd expose using a high contrast filter. Follow with a bleach.
Off hand that is the only method which comes to mind.
The bleach will effectively reduce the exposure and
do the more so as areas of greater exposure
are encountered.

Local contrast? The bleach acts most aggressively
in areas of greatest exposure. Is that not local
contrast control? Dan

Dan

Sounds complicated. It also sounds like a lot of trial and error. Maybe I give it a try to find out.

davidkachel · Dec 30, 2009

RalphLambrecht said:
Dan

Sounds complicated. It also sounds like a lot of trial and error. Maybe I give it a try to find out.

I must admit, that is a first! :confused:

No one has ever suggested before that SLIMTs are complicated.

Do you pre-soak your film? You don't consider that complicated do you?

SLIMTs are simply pre-soaks with a minute chemical content. (They are almost as close to pure water as a homeopathic remedy.)

Zeroing in on the correct concentration for any given print is dirt simple. Add a little record keeping to the effort and you should be able to make guesses as to the required concentration for new printings that are within one or two additional tests of being correct on the first try every time. You'll have already determined the correct bleach concentration for a given image long before you've devised your full burning scheme.

SLIMTs were designed to be ridiculously simple and substantially more effective than all previous traditional contrast reduction techniques. They work on all B&W photographic materials and all color photographic materials except reversal films and papers.

Now if you WANT complicated, try one of my other contrast reduction techniques, the Monobath Method (article to be found on the same web page). The Monobath method was designed for photographers who like to photograph solar eclipses from within missile silos. It works, but is sufficiently complex that even I don't use it!

dk

davidkachel · Dec 30, 2009

One thing I forgot to mention; if you should be in the process of developing a SLIMT treated print and realize you went too far with the bleach, a lot of the contrast reduction the SLIMT performed can be reversed by simply extending development time. SLIMTs attack surface latent image only. Extended development time cracks open undeveloped silver halide crystals and allows development to get at internal latent image.

removed account4 · Dec 30, 2009

i have my darkroom dim,
1 safelight a good few yards away from my sink
and a 150w bulb ( flood light ) for when i need to see anything.

carrots don't improve vision ...
http://www.snopes.com/food/ingredient/carrots.asp

but eating a lot of them will give your skin a nice orange glow

RalphLambrecht · Dec 30, 2009

davidkachel said:
...Do you pre-soak your film? You don't consider that complicated do you?...

Actually, I don't, because it can do more harm than good, but that's another story.

I said I will try your method, but it sounds complicated to me.

Stock Dektol · Dec 30, 2009

Just stare at the safe light when you first walk in.

dancqu · Dec 30, 2009

Also at Unblinking Eye

RalphLambrecht said:
I said I will try your method, but it sounds
complicated to me.

Search Google for, latent image bleaching . You'll
be at Mr. Buffaloe's site. He's worked with it.

Unsharp masking. And I suppose that's a breeze!
Unsharp masking? Latent image bleaching may
be a good alternative.

While hunting for the ballpark I turned out a few
over bleached 5x7s. High Key potential?

I prepared a 1% stock solution. At session time
a portion was diluted 1:9 and portion of that also.
The Kentmere Bromide was extremely sensitive;
final dilution, IIRC, a few one thousands of one
percent. An Arista paper 10 times that. Dan

RalphLambrecht · Dec 30, 2009

dancqu said:
Search Google for, latent image bleaching . You'll
be at Mr. Buffaloe's site. He's worked with it.

Unsharp masking. And I suppose that's a breeze!
Unsharp masking? Latent image bleaching may
be a good alternative.

While hunting for the ballpark I turned out a few
over bleached 5x7s. High Key potential?

I prepared a 1% stock solution. At session time
a portion was diluted 1:9 and portion of that also.
The Kentmere Bromide was extremely sensitive;
final dilution, IIRC, a few one thousands of one
percent. An Arista paper 10 times that. Dan

Unsharp masking is no breeze (who said that it is?). It is very time consuming but simple. But what does that have to do with latent image bleaching?

dancqu · Jan 1, 2010

Selenium -- Masking In Reverse

RalphLambrecht said:
Unsharp masking is no breeze (who said that it is?).
It is very time consuming but simple. But what does
that have to do with latent image bleaching?

Unsharp masking or latent image bleaching, either
method produces a print of lower contrast than the
same negative would produce minus either.

A mask effectively increases density more so
in the shadow areas of the negative. Latent image
bleaching effectively does the same chemically.

Post exposure latent image bleaching in effect reduces
the prints exposure; more so in the shadow areas. In
effect the negative's shadow areas are increased
in density.

I've not done any unsharp masking but have been
taking a look at Howard Bond's article on the subject
in an issue of Photo Techniques. "... if a negative is
a little too flat ..." he suggests the use of "...
selenium toner in order to obtain the
benefits of masking." Dan

RalphLambrecht · Jan 1, 2010

dancqu said:
Unsharp masking or latent image bleaching, either
method produces a print of lower contrast than the
same negative would produce minus either.

A mask effectively increases density more so
in the shadow areas of the negative. Latent image
bleaching effectively does the same chemically.

Post exposure latent image bleaching in effect reduces
the prints exposure; more so in the shadow areas. In
effect the negative's shadow areas are increased
in density.

I've not done any unsharp masking but have been
taking a look at Howard Bond's article on the subject
in an issue of Photo Techniques. "... if a negative is
a little too flat ..." he suggests the use of "...
selenium toner in order to obtain the
benefits of masking." Dan

Dan

There is a difference between unsharp masking and contrast masks, and sulphide toning works better than selenium toning to increase density and contrast, but we are really getting too far off topic right now.

dancqu · Jan 2, 2010

All in All

RalphLambrecht said:
There is a difference between unsharp masking and
contrast masks, and sulphide toning works better than
selenium toning to increase density and contrast, but we
are really getting too far off topic right now.

I know little of unsharp masking or of contrast masks.
I've worked with neither and have no intention of doing
so. All in all I think the discussion has shed some light on
latent image bleaching as method of varying the grade
of a graded paper.

So to connect to the OP's problem, one can have a graded
paper's higher level of darkroom lighting and still enjoy
papers with the potential of varying in contrast. And
vary in a very useful way.

Whatever the levels of safe lighting, that is whether one
uses VC or Graded, I believe David's advancement of the
latent image bleach technique worthwhile. An easy
addition to a darkroom worker's repertoire. Dan

RalphLambrecht · Jan 2, 2010

dancqu said:
I know little of unsharp masking or of contrast masks.
I've worked with neither and have no intention of doing
so. All in all I think the discussion has shed some light on
latent image bleaching as method of varying the grade
of a graded paper.

So to connect to the OP's problem, one can have a graded
paper's higher level of darkroom lighting and still enjoy
papers with the potential of varying in contrast. And
vary in a very useful way.

Whatever the levels of safe lighting, that is whether one
uses VC or Graded, I believe David's advancement of the
latent image bleach technique worthwhile. An easy
addition to a darkroom worker's repertoire. Dan

Dan

As I said, I'll give it a try, but you should try contrast masks. You should check Lynn Radeka's site. He is an expert. I have a feeling that they achieve the same thing with much more control. Nowadays, you can prepare them on the computer and print them together with the negative. I'll open a thread to discuss.

Roger Pellegrini · Jan 17, 2010

Get a Thomas sodium vapor safelight.

RalphLambrecht · Jan 17, 2010

Roger Pellegrini said:
Get a Thomas sodium vapor safelight.

They were not for me. The typical spot to mount them is on the ceiling in the middle of the darkroom. No matter where you are in the darkroom, you always work in your own shadow. Besides, they are expensive.

fotch · Jan 17, 2010

RalphLambrecht said:
They were not for me. The typical spot to mount them is on the ceiling in the middle of the darkroom. No matter where you are in the darkroom, you always work in your own shadow. Besides, they are expensive.

I was under the impression that they were used bouncing their light up and then it is distributed more evenly, similar to bouncing a flash off the ceiling?

I was interested in getting one until I realized that they would have a buzz or hum, just like outdoor lights.

RalphLambrecht · Jan 17, 2010

fotch said:
I was under the impression that they were used bouncing their light up and then it is distributed more evenly, similar to bouncing a flash off the ceiling?

I was interested in getting one until I realized that they would have a buzz or hum, just like outdoor lights.

The one I saw installed was hung a foot and a half below a white ceiling. The light did bounce off the ceiling, but it still was a central light, and I always stood in my own shadow. I prefer small, strategically placed safelight, where I need them.

Nicholas Lindan · Jan 18, 2010

Eat more carrots. Er, be sure you aren't suffering from a Vitamin A deficiency.

Some drugs can interfere with pupil response: some antihistamines, atropine, opiates, tri-cyclics.

You might try red safelights - they can be much brighter than the usual OC filtered variety.

michaelbsc · Jan 19, 2010

RalphLambrecht said:
... I prefer small, strategically placed safelight, where I need them.

I have to agree with this. I've got 4 dim little safelights scattered around the room. (Scrounge around on eBay and they're cheap enough.) Each bounces up to the ceiling/wall corner and paints the space under it to work. The room itself is rather poorly lit, but the direct work area under each light is completely adequate.

Since I don't have stuff in the middle of the floor, the fact that the floor is poorly illuminated is fine. And the only thing in the middle of the room between the dry side and wet side is open air.

Now, I'll grant you that if I have to find something it's a real bummer to look, because it's dark. But my paper doesn't fog.

RalphLambrecht · Jan 19, 2010

michaelbsc said:
...Now, I'll grant you that if I have to find something it's a real bummer to look, because it's dark. But my paper doesn't fog.

As long as it is safe for the operator, dim is good for the highlights and midtone contrast, and that's all that counts.

Ronald Moravec · Jan 23, 2010

Very bright red lights when no undeveloped/fixed paper is present.

Submarines used red in the conning tower so night vision was instant if they surfaced at night.

Put a well baffled 7 watt bulb somewhere and keep it off unless you drop something important.

What's the secret? eyes adjustment to dark

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