Efke Positive Paper

[Ektagraphic]

Hi Guys- I was wondering if any of you have ever printed slides onto the Efke positive black and white paper. It really intrigues me. I am hoping to pick some up soon.

Patrick

 

[Colin Corneau]

FWIW - I've used it to shoot 4x5 positive prints. It's very very contrasty...an effect that can be mitigated with different developers, ratios etc. But, considering copying usually adds contrast to begin with it may be doubtful.

 

[SAShruby]

Preflash the paper, it will lower the contrast, then you can use it with regular developers.

 

[Ektagraphic]

How long do you preflash for and with what kind of lightsource?

 

[Michel Hardy-Vallée]

Since it's a paper, it's far from being panchromatic, let alone even remotely orthochromatic.

cf. the pictures here: http://photo.net/classic-cameras-forum/00PyIp

Red objects are rendered pitch black, so it means that the emulsion is ordinary, and has little sensitivity beyond blue. Just bear in mind that it will have a much different rendition of your slides' colours than regular B&W film.

 

[Bill Harrison]

Didn't I hear this stuff was no longer available??

 

[Photo Engineer]

There are several threads on positive papers here recently.

PE

 

[tjaded]

Didn't I hear this stuff was no longer available??

Looks like Freestyle has it, but only RC

 

[wildbill]

I have printed color slides onto this paper, it's fun and awesome but I'm sad to see the fiber based paper go. I think I posted a print in my gallery earlier this year. The rc is available but there wasn't the demand for fiber and they axed it.

 

[AgX]

As a side note:

The emulsion is made by Ilford Imaging, seemingly to show that their devotion for direct-positive processes goes beyond their silver-dye-bleach materials. And the coating is done by Efke.

The production of this paper originated in this private enterprise: www.camera-imago.com

 

[removed account4]

SNIP SNIP

Since it's a paper, it's far from being panchromatic, let alone even remotely orthochromatic.

some of efke's films are ( or used be ) referred to pan-orthochromatic
because they rendered images kind of like olde fashioned ortho films,
but they were still pan-films .... how could a photopaper be not remotely orthochromatic ?

thanks !

john

 

[AgX]

John,

A paper without spectral sensitizers is is called un-senzitized or blue-sensitive.
Orthochromatic is a designation only used if a spectral sensitizer is added. Such would be the case to enhance speed of the paper, especially with light sources which not dominantely emit radiation out the blue spectrum, or to facilitate a variable gradation feature, etc.

 

[removed account4]

thanks agx

so regular old photo paper (plain vanilla emulsion) wouldn't be considered orthochromatic ?
maybe i am missing something here :confused:

- john

 

[Michel Hardy-Vallée]

John, most graded papers would be pretty much only blue-sensitive, aka "ordinary" emulsions. That's why you can use a yellow safelight. Efke's direct positive paper looks like it is thus.

VC papers, because they need independently controllable emulsions of differing contrast usually have a high-contrast emulsion sensitive to the blue part of the spectrum and a low-contrast emulsion sensitive to the green part of the spectrum. By using CC filtration, a specific ratio of exposure is given to each emulsion, thereby creating the resulting 00-5 contrast grade. So you need an amber or red safelight to avoid fogging the paper because it's sensitive to green.

In other words, the spectral sensitivity of VC papers is often close or equivalent to that of orthochromatic films, which are not sensitive beyond green.

 

[Photo Engineer]

Interestingly enough, all graded papers that I have tested are orthochromatic. In fact, they look just like their VC counterparts when tested identically with a wedge spectrogram.

PE

 

[Ray Rogers]

Interestingly enough, all graded papers that I have tested are orthochromatic. In fact, they look just like their VC counterparts when tested identically with a wedge spectrogram.

PE

Well, that doesn't make much sense does it?

I doubt the issue is one of exact wavelengths,
but anyway could you define your terms a bit...
Above what (minimum) wavelength constitutes "orthochromatic" in your tests?

What exact papers did you test?

I have seen all sorts of papers and some were and some wern't... but I think your observation is of interest, and deserves more study since it is known that variable contrast papers can be marketed as a graded yet variable contrast.

BTW, are you controlling for exposure/density in those tests?
What are the exposure times for those 2 papers?

Ray

 

[Ray Rogers]

Well, that doesn't make much sense does it?

Well on further thought, I can see some logic to such an approach, but I would be surprised to learn that was the only kind available anymore.

Anyway, I think the Efke paper here was a direct positive paper...
and I think it was only blue sensitive...
Was there ever a panchromatic direct positive paper made?

There were several Dir Pos systems developed... didn't one use red or yellow light? The Herschel effect or something? What possibility for color sensitization exist in such a system?

Ray

 

[Photo Engineer]

Ray;

My exposures used a spectrosensitometer with 1/2" - 1" times. It was a voltage controlled device using a Bausch and Lomb grating to generate the wavelengths from about 380 - 720 nm and typical exposures using this have been posted here. It is similar to the device used to generate the spectrograms in Mees and James.

I tested Luminos, Kentmere and Ilford papers. (well, I tested Kodak VC paper as well, but that does not count anymore. )

The typical test shows that graded papers can gain speed to white light via ortho sensitivity. The sensitivity and speeds of the graded papers look just like the VC papers except for the difference in contrast between the different layers.

See my post of Kentmere graded vs Ilford VC elsewhere on APUG.

PE

 

[Photo Engineer]

There were panchromatic direct positive B&W and color papers made.

PE

 

[Colin Corneau]

You can also find lower contrast developers, like Kodak's Selectol Soft and one by (IIRC) Zonal Pro...I ordered some from Freestyle and contrast is indeed quite low. A good match for that paper.

 

[Photo Engineer]

You can also reversal process most B&W negative papers just as you can reversal process most B&W films.

PE

 

[Ray Rogers]

Ray;

My exposures used a spectrosensitometer with 1/2" - 1" times. It was a voltage controlled device...

I tested Luminos, Kentmere and Ilford papers.

The typical test shows that graded papers can gain speed to white light via ortho sensitivity.

The sensitivity and speeds of the graded papers
look just like the VC papers except for the difference in contrast between the different layers.

See my post of Kentmere graded vs Ilford VC elsewhere on APUG.

PE

So the exposures were all less than one second?
That sounds like a pretty intensive exposure, appropriate for negs
Was it done by electronic flash?

I was led to understand that Luminos = Kentmere via rebranding or whathaveyou....

I will hunt up the Kentmere vs Ilford VC somehow, but I thought you were saying that _within a specific product brand_ the graded paper showed a similar color response to that of the _same brand_ VC product. That, while curious, I can see, but if you are saying you simply can't find any ordinary paper anymore that really IS strange.

I would want to know exact paper names and see the graphs myself before I would agree that the graded papers are now all orthochromatic...

Unless there has been an improvement made in the choice of the color sensitization dye for VC paper, the difference in required safelighting should be reason enough not to make ordinary graded papers orthochromatic. Traditionally, VC papers have required much less pleasent lighting than the single grade papers.

If what you observed is correct,
then the safelight reccomendations could be expected to be the same.

Do you agree?

Ray

 

[Photo Engineer]

Well, at identicl exposure times of 1/2" each for the Ilford, Luminos and Kentmere papers, which all have the same approximate speed on-easel, I would not expect the data to be skewed severly in any way. As for the Kentmere = Luminos, yes, but they are not necessarily the same emulsion, just made in the same factory.

I may have been wrong about having posted the spectrograms. I can't seem to find scanned images of the originals here. I have a lot of data to sift through though, so I may have missed it. If not, I can also re-scan if it becomes imperative that you see the data.

PE

 

[Ray Rogers]

...for the Ilford, Luminos and Kentmere papers... As for the Kentmere = Luminos, yes, but they are not necessarily the same emulsion, just made in the same factory.

I may have been wrong about having posted the spectrograms. I can't seem to find scanned images of the originals here. I have a lot of data to sift through though, so I may have missed it. If not, I can also re-scan if it becomes imperative that you see the data.

PE

That should really not be necessary.
(I am so far behind as it is, I shouldn't be looking for new distractions!)

It would be interesting to compare your results with published data, however,
and for you to compare old and new samples of the same material....

About the Kentmere = Luminos question:
"they are not necessarily the same emulsion, just made in the same factory."
Could be true, but I vaguely recall thinking that Luminos was to be Kentmere's American "Face".
I am not really sure but in this case,
I think they were substantially the same.

 

[Photo Engineer]

Ray;

I got Kentmere and Luminos at exactly the same time from the same dealer. So.....

I cannot tell if they are in any way the same emulsion.

Kentmere is now made in the Ilford plant, so the whole landscape changes.

PE