National Fotocolor One-Shot Camera

[Gord Robinson]

Sandy that is a striking image made from the separations. From what I understand (this is not gospel) Photoshop has some type of automatic registration program in it's newer versions which would make aligning the negatives a lot less time consuming. My original quest for this summer is to make tests to see if the pellicles in my NPC One Shot Camera and still in good enough shape to make separations for Dye Transfer prints but now that I have seen what you have done in Photoshop I am wondering that if the negs are not acceptable for Dye Transfer than I could use PS to correct them to make digital prints. My camera came with a set of 30 matched glass plate film holders and I am now using a set of septums and TMAX 100 and Tri X cut down to 3x4
to make the camera useable. I have a couple packs of HP3 glass plates but I would think that they are well beyond the "best before date" to be usable for any separation work. Thanks for directing me PS for an alternative method of combining the separations.

Gord

[sanking]

Gord,

The color separations layers can be aligned in Photoshop CS3 or CS4 by use of the File>Script>Load Files into Stacks. Use Browse to load the files, check auto-align, and then click to go. Since the files should be grayscale at ths point it goes pretty fast, even with large files. I processed another old three-color separation set today using the above method and alignment of the three files was perfect. The image is attached. The separations from this set are among the first ones I ever made, on an old Ansco ASA 400 Superpan film, and are very mismatched in terms of both density and contrast but as you can see it was possible to adjust this in Photoshop to make a pretty pleasing image.

The amount of correction that can be done in Photoshop for good in-camera separations will astonish you. In the old days it was very important that the three color records have the same density and contrast. However, with Photoshop one can correct very large density and contrast mismatches.

Sandy King

Sandy that is a striking image made from the separations. From what I understand (this is not gospel) Photoshop has some type of automatic registration program in it's newer versions which would make aligning the negatives a lot less time consuming. My original quest for this summer is to make tests to see if the pellicles in my NPC One Shot Camera and still in good enough shape to make separations for Dye Transfer prints but now that I have seen what you have done in Photoshop I am wondering that if the negs are not acceptable for Dye Transfer than I could use PS to correct them to make digital prints. My camera came with a set of 30 matched glass plate film holders and I am now using a set of septums and TMAX 100 and Tri X cut down to 3x4
to make the camera useable. I have a couple packs of HP3 glass plates but I would think that they are well beyond the "best before date" to be usable for any separation work. Thanks for directing me PS for an alternative method of combining the separations.

Gord

[Gene McCluney]

This is quite striking. Can someone explain to me how it works? I can't seem to get my poor mind around it.

You expose three sheets of panchromatic film, each through a separate primary color filter. So each sheet records the amount of one color in the scene. When you combine the image, tinting each b/w record its complimentary color you get a full color print.
(I hope this is the correct simple description). A tri-color camera simplifies the process by exposing three sheets of film at once from one lens thru a beam splitter and three filters. Splitting the whole color spectrum into three colors is the basis for all color photography practiced today, film or digital. It is just that modern color films expose three layers in the film emulsion, one on top the other through built-in filters. There are 3 dyes in processed color film representing when combined a full color spectrum. Modern digital cameras have 3 primary color filters over alternating pixels.

[bvstaples]

When you convert the RGB by subtractive, you end with with CMY. What about K (black)? How is black brought into the image?


Brian

[Gord Robinson]

Thanks Sandy for the PS alignment info - I will dig out some old separation negs when I have some time and give this a try. I don't use PS a lot so it will take some time to figure it all out.

Gord

[Gene McCluney]

When you convert the RGB by subtractive, you end with with CMY. What about K (black)? How is black brought into the image?


Brian

In color photography using dyes, there is no "K" (black). Maximum amount of all three dyes produce black.

[Struan Gray]

Sandy, is the main difficulty with colour carbon a physical one of handling the tissues, or is it the conceptual problem of previsualising the effect of all those stacked transfer characteristics?

If a digital step can tame some of the complexity and make things a little more predictable for a beginner, colour carbon is something I have always wanted to try.

[sanking]

There are several main difficulties in carbon printing. First, there is at present no supplier of color carbon tissue so you have to make your own. This may change soon as B&S in Santa Fe has indicated that they will supply color tissue at some time in the near future. But for now, there is none.

Another difficulty is that completion of a print requires several wet/dry mating stages that are quite sensitive to humidity and temperature. Even the sensitivity of the carbon tissue can vary a lot with changes in RH and drying time so getting color balance can be very challenging.

Previsualizing what the final image should look like is not a problem today if you assemble the images on the computer and print digital separations. Before digital photography getting the negatives right in terms of density and contrast demanded a lot of skill in exposure and development but today it is possible to correct almost any separation set.

By the way, there is a couple in Sweeden knowns as Hans and Chia who do good color carbon work. They are located in Goterborg, I believe.

Sandy King

Sandy, is the main difficulty with colour carbon a physical one of handling the tissues, or is it the conceptual problem of previsualising the effect of all those stacked transfer characteristics?

If a digital step can tame some of the complexity and make things a little more predictable for a beginner, colour carbon is something I have always wanted to try.

[Drew Wiley]

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.

[dazedgonebye]

Fascinating idea. I'll have to try it at least once.