National Fotocolor One-Shot Camera

[sanking]

Jim has been a great source of information for me. I think he actually has a NPC 5X7, though it may be same as a Devin. At one point NPC and Devin appear to have combined.

I don't understand your use of the term "beamsplitter"? Pellicles are commonly referred to as beamsplitters since this is essentially what they do in one-shot color cameras.

Sandy King

There's quite a bit of info on dyetransfer.org about restoring tricolor cameras. Complicated. Jim Browning uses a 5x7 tricolor Devin. The three separate films are scanned and aligned in Photoshop, then output to his homemade 40K film recorder
with registration pins, then finally to DT matrix film. The end result is a tonal range impossible for any current color film or even digital camera. It would be easier to make
a tricolor camera from scratch using a beamsplitter rather than separate pellicles,
but very expensive. Technicolor movie cameras are based upon this idea.

[Bill_1856]

Don't forget that for still subjects it's easy to make sep negs by shooting three B&W exposures in one camera through tri-color filters.
I have a really neat tri-color filter set made by Leitz for the Leica, which is attached like a regular screw-on filter and rotated to make the three sequential shots as fast as the film can be advanced.
I'm always amazed at those "instantaneous" Russian pictures taken near the turn of the 20th century with a camera which dropped the filters between the lens and the film. My surprise is that I didn't think there was red sensitive film at that time.

[Marko]

This is the image I did a while ago using Cokin red and green and Hitec blue filter in a Cokin holder. Tri-X in D76.



I combined the scans into an RGB image by merging channels from grayscale images. Had to do a lot of adjustments and cleanup since the filters where not real color separation filters, but it worked relatively fine for a simple test.

Tried the same thing with a violet/blue-colored orchid, but wasn't happy with the results, no matter what I did, I couldn't get the blue and violet right.

I think I will have to use an apochromatic lens and better set of filters.

[sanking]

Bill,

All of my separations from the past were made that way, i.e. making three successive exposures with a view camera changing the filters, Red first, then Green, then Blue. I was usually able to make all three shots within 20 seconds or less.

Using a regular view camera has some obvious advantages over one-shot cameras. The typical view camera is much lighter and compact than a one-shot camera of the same format, flare from reflections is less of a problem, and shutter speeds can be much faster as each film gets all of the light, whereas with the one shot camera it shared three ways. Also, the negatives made with the view camera are more consistent in size since the pellicles, if not very precisely registered, warp the image slightly for the Blue and Red records.


Sandy King

Don't forget that for still subjects it's easy to make sep negs by shooting three B&W exposures in one camera through tri-color filters.
I have a really neat tri-color filter set made by Leitz for the Leica, which is attached like a regular screw-on filter and rotated to make the three sequential shots as fast as the film can be advanced.
I'm always amazed at those "instantaneous" Russian pictures taken near the turn of the 20th century with a camera which dropped the filters between the lens and the film. My surprise is that I didn't think there was red sensitive film at that time.

[Bill_1856]

FYI:

http://www.loc.gov/exhibits/empire/making.html

[Drew Wiley]

I spent quite a bit of time last year "reinventing" separation negatives. Using TM100
and a special developer tweak I found I could get very high-quality matched straight-line separations darkroom-style without resorting to photoshop at all. Of course, just one variation in materials and there goes a lot of work down the drain. So that's right when Kodak decided to downsize their boxes of 8X10 film! In such cases, you have to be certain all your film comes from the same batch and buy in multiple boxes. And a
good separation for DT work is quite a bit different than one for carbon, and even
varies with the specific dyes used. For now I have to store the separations and hope
I have time after I retire to deal with them. So little time, so many negatives!

[sanking]

Prokudun Gorskii was certainly among the first to utilize panchromatic films and he left an incredible body of work that clearly make him one of the greatest color photographers (if not the greatest) of his time. Digitizing and making it available to the public is one of the most important achievement of the Smithsonian. According to the link his first work began in 1909 and lasted until 1915. Panchromatic plates were first introduced on the market in 1906 by the English firm Wratten and Wainwright.

Sandy King

I'm always amazed at those "instantaneous" Russian pictures taken near the turn of the 20th century with a camera which dropped the filters between the lens and the film. My surprise is that I didn't think there was red sensitive film at that time.

[sanking]

My interest in sensitometry dates from the demands of producing separation sets matched in contrast and curve shape for color carbon printing. Most of my very early work, including the images I have included in this thread, produced very mis-matched separation sets. After I learned how to precisely control exposure and development it became easy enough to produce balanced separation sets, and all of my better separations are on Kodak Super XX film, which was long the standard for color separation work.

The job of learning to make color separations on B&W film is definitely not for those who seek instant gratification as the learning curve is very long. But for me it was always a huge amount of fun doing this kind of work, and having fun has always been the main motivator for my photography. I have always been much more interested in the doing of photography than in the final result.

Sandy

I spent quite a bit of time last year "reinventing" separation negatives. Using TM100
and a special developer tweak I found I could get very high-quality matched straight-line separations darkroom-style without resorting to photoshop at all. Of course, just one variation in materials and there goes a lot of work down the drain. So that's right when Kodak decided to downsize their boxes of 8X10 film! In such cases, you have to be certain all your film comes from the same batch and buy in multiple boxes. And a
good separation for DT work is quite a bit different than one for carbon, and even
varies with the specific dyes used. For now I have to store the separations and hope
I have time after I retire to deal with them. So little time, so many negatives!

[Struan Gray]

Sandy, thanks for the info. I'm not afraid of making tissue and experimenting with the hands-on craft of print making, but I know from experience that I learn best when I can practice and experiment in a concerted manner, and for now other commitments preclude that. It's fun to dream though, and to plan ahead for later - I just know that colour carbon or some sort of colour intaglio work lie in my future.

My own interest is in the freedom to choose pigments and filters at will, without being necessarily tied to the standard primary and secondary colours. To have the freedom of a printmaker or painter in choosing colour renditions, while still being tied to reality through the lens, seems like a great combination.

I think you've linked to Hans Nohlberg and Chia N-Löfqvist's work (www.pictoform.nu) in one of your online articles - I'm pretty sure I got the link from you. Their colour carbon on glass really tickles my fancy.


A pellicle is a beamsplitter, but it splits all colours evenly, which is why tricolour cameras using pellicles have colour filters somewhere too, often close to the focal planes for each colour. What I think Drew was referring to is a technology used in 3-chip video cameras and some technical cameras, where the splitters are dichroic mirrors and only divert particular colours: the spatial separation and the spectral filtering are done in one step. Because no red light is sent towards the green film/chip there is no intensity disadvantage over using a sequence of filters in front of a regular camera. The systems I have seen all use prisms with imaging chips face-mounted onto the prism faces (which solves the alignment problem nicely). This would be very very very expensive and heavy for LF formats, but doable, albeit on a military-style budget.

Thanks again. I'll come and take a workshop when I get serious :-)

[isaacc7]

FYI, there have been quite a few astrophotographers to use color separation techniques. It was the only way to get acceptable color results because of the funky reciprocity issues of the different layers of color films. Believe it or not, the most common film used for this was tech pan that had been hyper-sensitized. Total exposure times for deep space objects routinely ran into the 7 or 8 hour mark! This page has a really good primer on the subject:
http://www.rphotoz.com/astrophoto/tricolor.html

There are some amazing examples of this type of photography on the net, they are technical tour de forces!

Isaac