Color pictures from B&W vs. Color film

[Randy H]

This thread started out about monetary savings, but in reality...? Look at the price of the toys we are playing with. It is kinda like the thread a couple days ago from Cyrus on photogravure. That is too cool. And I KNOW it couldn't have cost more than a few pennies per pic
I have been playing with the idea of photogravure and even have the old tasope 10X12 process camera and lens in preparation for it. Just haven't had nerve enough to jump off into it yet. Methinks we just all junkies to photography, eh?

[Gene McCluney]

what about the blue skys? red and green clouds?

With a 2 color system, you do not get pure blue skies. You get cyan-greenish skies, but you can get fairly accurate skin tones. Early 2-color motion pictures designed their sets and scenes to harmonize with the 2-color process, so you won't see many skys in these movies. And 2-color portraiture was almost all studio, where the background was controlled.

[bglick]

Peter, of course the paths are equal, otherwise, they would be out of focus.... but the paths are different.... However, each part of the image should be equal distance from the nodal point for all 3 images. So, now I am confused where the parallex is created?

[Peter K]

Of course the rays of the center of the three images are going through the back nodal point of the lens, depent on the construction of the camera also through the front nodal point. But it's the same with panorama images, the nodal point is fixed, but the three images are taken from different angles. So you get three different images and they cannot registered.

With a real beamsplitter like it was used with Technicolor cameras or old color TV cameras equiped with three plumbicons / vidicons there is no problem. But for a LF camera one needs a glass cube with 5^3 inches.

There where cameras with mirrors used as beamsplitter aviable, but with this cameras one gets double images from the front- and the rear surfaces of the mirrors. Also cameras with big glass prisms where buildt. But all this very expensive glass couldt not improve the images.

[bglick]

> But it's the same with panorama images, the nodal point is fixed, but the three images are taken from different angles. So you get three different images and they cannot registered.

Peter, this is not a fair comparison. With nodal point rotating panorama shot, you are 1) taking 3 separate exposures, 2) you are changing the composition with each shot. This is NOT the case with this 3 film, single shot system we aer discussing, there is only ONE exposure being taken. So only ONE image is being passed to the beam-splitters. The only possible cause of parallex is possibly some mis alignment. But if there is NO mis alignment, I am not seeing any reason for parallax.... you should get the identical image on each film. If you think I am in error, can you please explain where exactly I am error? Or maybe we are talking about two different types of technicolor set-ups? I am referring to the Devin set-up in the link Henri provided??

[Henri Gaud]

With a 2 color system, you do not get pure blue skies. You get cyan-greenish skies, but you can get fairly accurate skin tones. Early 2-color motion pictures designed their sets and scenes to harmonize with the 2-color process, so you won't see many skys in these movies. And 2-color portraiture was almost all studio, where the background was controlled.

Some news about bichromy : the two color système.

here

Here

How make bichromy

[Peter K]

It is the same with tricolor-cameras like the Penrose, Jos-PE and Camera Sunshine, the last on Henri's link: three exposures through one lens, each exposure differs a little bit in the angle of view.

With cameras like the Bermpohl and Devin the images are taken from the same angle, but with the mirrors used one gets double- and ghost-images because the reflecting surfaces could not be made thin enough. Today it is possible to make a beamsplitter with interference filters embedded in glass. So the reflection surface is very thin and there is no jump in the refractive index, but one can buy many color films for the money such a glass cube is worth.

[Henri Gaud]

<<Today it is possible to make a beamsplitter with interference filters embedded in glass. <<

Yes it is possible, but for few camera it is very very expensive.

[bglick]

> Yes it is possible, but for few camera it is very very expensive

I see these beam splitters used in many visual optics, where it splits one image into 2 images, one for each eye. If their was ghosting or scattering, the eye is very sensitive to any form of rivalry and it would be immediately noticeable. However, that is NOT the case. And these products are sold very cost effective....but, for 4x5, the Beam splitters would be much bigger, so maybe the cost would go up significantly. I guess this is why I was confused.... back in the early 1900's, I guess the technology for the beam splitters is not up to par with what we have today, whereas this camera could be built without too much difficulty today, albeit maybe very expensive. And with all this difficulty, of course, color film is the obvious choice.

[Peter K]

Binocular tubes for microscopes where made since the middle of the 19th century e.g. by Nachet et Fils in Paris, also the Lummer-Brohum cube comes from the 19th century. So beam-splitter where state of the art at the beginning of the 20th century, the time color photography was in progress. Small band interference filters where aviable in the sixties. But such big cubes of optical glass where always very expensive. And heavy too.

And only necessary for a photographic system not better as modern color photography.