Experiments with RGB-colored screens... a la Dufaycolor & Autochrome

[holmburgers]

Hmmm, yeah i should try that. but i don't think the two colour theory would work in that situation. I think the separations would have to be layered on top of each other. I don't think it would work if they were side by side.

I'm not sure if you understand how screen-plates work. Yes, of course they would work side-by-side... that's how Autochromes, Dufaycolor, Paget plates, my example, Stephen's example all work.... that's how your TV works to make color!

The fact that it's two color would have no effect, and I have no idea what you mean by 'on top of each other'. As long as the orthochromatic film was equally sensitive to blue and green (and I have no idea if it is) it would work with those two colors and produce some semblance of reality, much like any historic 2-color approach is capable of.

Also, I'm not clear as to why we're talking about color "separation" filters. I know that Ray brought it up, but unless you're making separations from your screen plate photograph, they have no purpose whatsoever in the picture making/taking process of a screen plate... unless you plan on cutting them up and mixing them as PE suggested for his "confetti" idea.

 

[happyjam64]

I understand how these screens work, but have a look at http://www.greatreality.com/Color2Color.htm then you'll see what I mean.

 

[Photo Engineer]

White light is only properly defined by the entire spectrum of a given light source from 400 - 700 nm. It cannot be defined by a human eye. Within this limitation, films are defined by their sensitivity to any given wavelength by a wedge spectrogram and then the film is assigned a name such as orthochromatic or panchromatic along with additional qualifiers such as tungsten or daylight balanced. So, I again maintain that there is no such thing as a white light film nor is a human being able to define a white light beyond saying it appears white to them.

Tricolor separation filters can generate what appear to be full color images and even white light, but they do so using a discontinuous spectrum the extent of which depends on the width (or half band width) of the filter set.

Within this limitation, color blind people can see what they define as white but we have no way of telling if it is truly white, they have just defined it so in their minds. Kodak tests everyone for color vision and those that fail the several tests given them cannot work on color products.

PE

 

[Photo Engineer]

I understand how these screens work, but have a look at http://www.greatreality.com/Color2Color.htm then you'll see what I mean.

Remember that early color systems were 2 color.

Land improved on this using the method I posted earlier, but appears to have been unable to bring it to fruition. Like many inventors, as I mentioned, he had a lot of ideas but could not make many of them work in a practical fashion. Many here know the story of Polacolor. Land could not make it work so Kodak did his R&D for him and actually manufactured it for him until his own plant could make it satisfactorily. This may be the case here as well. He had a lab idea which he could not get to work outside of the lab.

Or, it worked and was no better than the early color systems and he dropped it.

PE

 

[holmburgers]

I understand how these screens work, but have a look at http://www.greatreality.com/Color2Color.htm then you'll see what I mean.

Ahh, ok, I see what you mean. Sorry for the backlash!

Land's experiment does sound quite interesting but indeed I'm not sure how one would do that with screen-plates.

I still think the ortho idea is intriguing and worth trying. We might be surprised at the results.

Is an ortho-film's sensitivity conducive to this kind of 2-color screen? That is, equal blue and green sensitivity? I guess if not, filters over the lens could balance it out.

edit: Actually, this raises the idea of using a separate taking screen and viewing screen. This raises serious issues w/ registration, but, this could allow you to make a screen plate resembling color infrared film, for example. Imagine this.... you make a screen plate from a TV, except that you use a deep cyan filter. This would not effect the blue/green elements but would darken the red elements. Everyone knows that opaque, processed slides are IR transmitting, sooo, in theory you could have a IR record on your screen plate. Then, place the appropriate screen plate for viewing and you could have false color images. Granted, balancing exposures on such a plate would be troublesome, but this idea could be utilized to try something similar to the 2-color approach of Land's.

 

[Ole]

Remember that Autochromes were exposed through a rather dark brownish-orange filter, to balance the film sensitivity and the absorption by the dyed starch grains..

 

[happyjam64]

Yeah, for sure the ortho idea is one to try.
I never thought of making a false colour screen. I think that would be a great idea! Or, what if one made a screen with red, green, blue and infrared filters? So when the image is projected, it can be projected with different screens to create different false colour images!
But one step at a time folks, haha.

 

[michaelbsc]

So, let me ask about the "white light" x-ray dupe film mentioned elsewhere. I realize the description was really meant to differentiate it from the UV sensitized similar product, but did anyone ever determine if it is actually pan-chromatic of not?

MB

 

[holmburgers]

Yeah, for sure the ortho idea is one to try.
I never thought of making a false colour screen. I think that would be a great idea! Or, what if one made a screen with red, green, blue and infrared filters? So when the image is projected, it can be projected with different screens to create different false colour images!
But one step at a time folks, haha.

That would be truly awesome! And they thought screen plate's had run their course.... think again.

Michael, I'm pretty sure the x-ray dupe film is not panchro.

 

[happyjam64]

holmburgers is right, i read the thread, it's not pan.

 

[holmburgers]

So last night when I was driving up a spiralling parking garage [*warning* superfluous information] the thought occured to me that I've never actually heard how autochrome plates were assembled. Did you separate the screen from the emulsion to process and then re-register? (I don't think so) Or was the panchromatic emulsion simply coated on the back of the glass plate screen and the whole shebang went into the soup? That's what I imagine being the most likely, but I've simply never heard it described.

In other news: my test roll of various filtrations for the CPU monitor and CRT TV is off to the lab to get processed, so hopefully one combination will yield a neutral gray for each source.

For the TV I used wratten 3, 6, 8 and 9 (IIRC) to eliminate the bluish cast, and on the CPU monitor I did CC-magenta ranging from 10-50 and one with a pinch of CC-cyan; with the goal of eliminating the terrible green cast. With all filters I did +0, +1 and -1 exposure.

However, I think that my unfiltered and bluish TV screen plate did an excellent job as a tungsten screen. I'll confirm this in the future.

Also, the gelatin binding of the two sheet films still holds promise, but not until I can figure out a better way to separate the two. They bind very strongly and undoing them, even slowly and carefully, has resulted in lots of blemishes on the films. So, I decided that I need something to make the gelatin more soluble and PE suggested Sorbitol or Carbowax, but not glycerin which is too sticky.

First I'm gonna try Sorbitol, which is easily available as an over-the-counter laxative (bonus... dual purpose!) and I'll report back. Any idea what concentration to start out with?

 

[Stephen Frizza]

Ok no offense to anyone who has posted here and I stress this is just a general comment its not directed at anyone. This thread was started on the subject of RGB screens. Why over complicate a relatively simple concept? the places this thread has gone makes me scratch my head in wonder!!! lets keep this simple concept simple! RGB screens work in their simplest form and simple works well.
some of the things i have read here make it sound like people are wanting to go around the sun to meet the moon.

 

[holmburgers]

Stephen, how did you obtain good optical contact between your screen & film?

I for one enjoy discussing all sorts of hypothetical & theoretical conditions and if you read, you'll see that lots of brand new ideas have been introduced; false color screens, two-color screens, the use of LCD screens as dupe-masters, and more if you dig. Sure there's a lot of back-tracking and a lot of detours, but we're all hear to learn and collaborate.

But I do agree with you that's it's easier to talk than walk and walking's the only real way to get somewhere.

 

[Mustafa Umut Sarac]

walkie talkie

 

[holmburgers]

Color Fit For A King

Make a screen-plate of rubies, emeralds and sapphires. Crush them to get the right size. Coat this onto a large piece of fuzed quartz using fish glue from the Coelacanth, substituing lamp black for this stuff.... http://www.sciencenewsblog.com/blog/130081.

Since the particles will undoubtedly be rather large, a large format will be necessary. How about 20x24"? We'll need this lens... http://www.bhphotovideo.com/c/product/373457-REG/Schneider_04_1056263_1100mm_f_22_Fine_Art.html

If any color correction filters are necessary, they should obviously be dichroic and orderd from Roscoe... http://www.bhphotovideo.com/c/produ...0310807000_Permacolor_3180_Glass_Primary.html

Any film will do, but a special order from Kodak of Technical Pan should suffice.

After the picture is taken and developed, a platinum print should be made of the black and white records, again, on fuzed quartz.

The two plates can now be sandwiched together, again, with Coelocanth fish glue, and displayed.

 

[Mustafa Umut Sarac]

When US Scientists invented making laser beam out of ruby light amplifier , Soviet Scientists found it silly and invented their technology. It was about sintering inorganic powders with microwaves and producing giant rubies , thats materials called Zirconia.
So good news , its very very hard to understand which material is real gem , what is not. Its so similar.
You can find sites which sells a very big cut zirconia emerald for few dollars.
Its not for kings or megolamaniac narcicists but it works. I liked the idea. 11000 dollar Leica Noctilux uses the same material. It comes may be in 40 colors and they are damn cheap.
You can make very thin powders with hand blowns within a porcelain cup and a hand blowing hammer.

 

[holmburgers]

Well, me being a peasant, zirconium sounds good

 

[holmburgers]

LCD Screen from digital picture frame

Ok, so an APUGger by the name of R Paul has been PMing me and furthering the idea of using an LCD screen from say... a portable DVD player, or a digital picture frame. Banjopete had this idea a couple pages back in the thread.

He sent me some pictures of one that is 5"x7" and no doubt it would make a great screen-plate. He asked me to post them.

It could be used by itself, or could be copied by contact onto slide film.

Thanks for sharing Rob!

 

[Stephen Frizza]

I have 3 questions about LCD screen, firstly how flexible are the screens? Secondly does anyone know the filtration values of the Red the Green and the Blue. do different screens have different intensities of red green and blue? and thirdly how course are these screens? just from the scan here the screen is looking really rough and there isn't even an image on it yet.I dont think these kinds of screens are the best way of going about this.

 

[R Paul]

Hi there
Well first off, the screens are made of thin glass and are about a millimeter thick. secondly I don't know about the filter factors of the RGB pixels. And lastly from the specs I've looked up a 6x3 inch screen with a resolution of 480x234 should have should have pixels of about .01 inch square. This would depend on the actual screen size as opposed to including the actual plastic around the frame,etc.
However a 5.8x7.7 inch screen with a resolution of 800x600 works out to a pixel size of .007x.01 inch which seems better . I don't know how well these screens would work in practice, but I am constructing a film holder that will hold the screen plate I have in order to test it out.
I think it's worth a test because these frames are so cheap now, and it seems the easiest way of getting hold of a screen plate, short of actually constructing one yourself. At least if it bombs out,then you know for sure and can think of something else .

rob

 

[holmburgers]

The resolution will be indentical to viewing a digital picture on one of those LCD digital frames, and if you've ever seen one, they certainly don't look coarse or grainy, about what you would expect from a computer screen.

Since these screens are lit by a large fluorescent backlight, the color elements will be balanced de facto, at least to a certain extent.

I think the roughness of the screen in the picture is coming from aliasing and moiré problems.

 

[R Paul]

Hi
Finished the screenholder couple days ago and tried it with some TMX 100.

Unfortunately the film didn't reverse, and the negs are thin, so there's more work to be done . I accounted for exposing thru the screen, but maybe my shutter is off.
Next time I will try the focal plane shutter
rob

 

[holmburgers]

Awesome,

I thought I accounted for my screen too and got really dense positives myself, so I guess better over-compensate. Another thing... since the screen adds density no matter what, a proper positive should be pretty over-exposed me thinks.

Looking forward to seeing it!

 

[holmburgers]

Last night, for the first time, I adhered a screen plate with a sheet of Delta 100. I used my gelatin, sorbitol and photo-flo concoction to glue them together and let me tell you, doing this in the dark was quite a thrill..

I created a registry board and taped off the screen which is the only surface that shouldn't get any solution on it. Gunk on the back won't affect the image.

I put the wet sandwich (sounds delicious) hanging in a basket in a film-changing bag and put one of those tiny 4" duct fans in one of the arms to aid in drying. Tonight I will put it in the film holder, which is a typical 4x5" holder that I sanded the channels out to accomodate double the thickness.

Once I turned on the lights, there was a fair bit of dye mixed in with the left over, spilt gelatin. Being sensitizing dye from the Delta 100, I hope it doesn't ruin it's sensitivity. We'll see...

I'm doing this to avoid the problems I had in my first test with registration. Two films when dry don't sandwich very completely, so a method to bind them optically is important. A little birdie gave me an alternate method, which if this one fails miserably I will try. That method is to introduce a slight bend in the film-sandwich and that should keep them pretty much in contact.

There are also some old methods used by the bi/tri-pack people to adhere two films and yet have them easily removable. Perhaps searching those patents would also give some good ideas.

 

[Photo Engineer]

The bend method introduces focus problems though. Beware!

PE