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

holmburgers · Oct 25, 2010

How do you propose to re-apply an identical, stochastic, screen? I think that would next to impossible, as each screen element has to be in exactly the same place during exposure and viewing.

Q.G. · Oct 25, 2010

The coloured starch grains in the emulsion worked as screen in the original autochromes for both exposure and viewing, didn't they?
No need then for external masks.

holmburgers · Oct 25, 2010

Yes, there'd be no other way to do it with a stochastic screen like that.

Q.G. · Oct 25, 2010

So problem solved by not being a problem.

holmburgers · Oct 25, 2010

I'm confused... what problem, whose problem?

This is becoming a problem....

Problem

Photo Engineer · Oct 25, 2010

You cannot use a "screen" process for color photography unless you view using the identical same screen in register with the B&W screen produced positive. It will not work any other way! You cannot remove the screen and generate a new one as the new one, using the method proposed, will not duplicate the original.

PE

Stephen Frizza · Oct 25, 2010

my technique was to make a screen in photoshop using straight lines of Red, Yellow,Green, Cyan,Blue (NO MAGENTA). I found this produced a better colour result with ERA 100 film. the screen i made was output using a Lightjet onto duraclear material. Post processing the screen is re registered with the film to produce a colour image. interestingly the scanner produces a nicer white and so does the print from the film however when viewing the film through the screen the whites are more a grey. The linear screen while easier to register also greatly reduces the overall image quality. My sample is a cropped 4x5. perhaps I will get better quality if i shoot on 8x10" and reduce it rather than enlarging. if your screen Isn't registered correctly you will get very annoying colour aberrations and failures. I hear a lot of people talk about how hard it is. but i think as Photo Engineer says if you use the same screen you exposed with for the final registration and you have the equipment to register the film to a screen then it really isn't too difficult. the bigger challenge will be in finding a suitable black and white film and figuring out how to effectively reversal process it. I think this process could be applied to making colour negatives however when looking at everything in negative it can become quite difficult to judge what actually going on with the colour so for now and for a long time i think i will only apply the method to positive process black and white.

Athiril · Oct 26, 2010

I will be trying negatives first - proof of concept, I can reverse them in scanning.

holmburgers said:
How do you propose to re-apply an identical, stochastic, screen? I think that would next to impossible, as each screen element has to be in exactly the same place during exposure and viewing.

By having an evenly distributed screen. I'll see if it works or not.

Photo Engineer said:
You cannot use a "screen" process for color photography unless you view using the identical same screen in register with the B&W screen produced positive. It will not work any other way! You cannot remove the screen and generate a new one as the new one, using the method proposed, will not duplicate the original.

PE

Unless I have an evenly distributed screen right?

Mustafa Umut Sarac · Oct 26, 2010

Easiest way to real autochrome :

I think Someone can print a screen to one side of polyester film like melinex. Than coat this side with clear epoxy or high refractive index polymer and than spray a emulsion to the other side.
Take picture , positive develop , voila you get the color picture.

One can buy my museum color chemicals recipes and use at a printer and you get the autochrome colors.

I think Someone who want to print this screen , might add black also.

If I dont get too much reaction from this post , I will post at another thread.

I think I will ask to Sigma Chemical Materials distributor that which color original autochrome chemicals would be able to be printed by inkjet printers. If you plan to buy a printer , I read that older the printer better the chance to use wider gamut of chemicals.Someone reported that newer the printer , printer head is wiser and require only the special ink formula.And another problem is HP print with heat and EPSON print with pressure.In my view , epson is more logical but I have to learn that whether they work with strange chemicals.

Let me research original autochrome chemicals , their viscosity and post to here and recipe thread.
I think they are hidden at Photo Engineer section.

I need to learn is spray emulsions sticks on to the melinex like kodak emulsions or do they need to be sanded or plasma treated.I think someone could create giant size autochromes on LF cameras.

Another technique is to buy LF film and print screen to the nonemulsion side. Than spray a anti halo spray - like drum scanner operators like me - uses and strech and band to the glass without leaving a gap between film and glass. I think this band could be rectangular , parallel to the sides of film

Take your picture , develop , remove the bands and voila , you get autochrome.

Best ,

Mustafa Umut Sarac

Istanbul

Photo Engineer · Oct 26, 2010

Athiril said:
I will be trying negatives first - proof of concept, I can reverse them in scanning.

By having an evenly distributed screen. I'll see if it works or not.

Unless I have an evenly distributed screen right?

By painting on the "screen" it is by definition unevenly distributed and not positioned the same after you reapply it.

The only way to achieve the color image is to have a screen that is identical before and after processing and to have it positioned in exactly the same place and in the same manner before and after processing.

PE

Q.G. · Oct 26, 2010

And that is easiest to achieve when you incorporate it in the film. Coloured starch in an extra layer.

holmburgers · Oct 26, 2010

Stephen Frizza said:
my technique was to make a screen in photoshop using straight lines of Red, Yellow,Green, Cyan,Blue (NO MAGENTA).

Did you experiment with just red, green and blue before going to this 5 color system? What was the result with magenta that led you to not use it?

In reading about the history of screen plates there have been examples of people utilizing rainbow colored screens and the like, all in the hopes of more real color. But it actually serves to desaturate the colors, since it's an additive system and subtractive-complementaries are wider-band than red, green & blue. But, perhaps there are other advantages (like speed) and as they say, the proof is in the pudding and your example looks great! So whose to say...

And yes, I'm afraid Athiril, that if you're truly "painting" on the starch then it'll be a total failure. Not to say you shouldn't try and see for yourself.

But think about it; imagine a picture of a banana. The yellow reflected light from it will go thru the green and red elements in some proportion and be mostly blocked by the blue. Consequently, upon reversal processing (for example's sake, negative processing gets same result but... well you know) the clearest portion will be behind the green, with a gray behind the red and hi-density behind the blue. These are called tristimulus values; the relative luminosity of RGB in an additive system.. exactly like a TV. If this condition is not met, your color will be meaningless/no relation to reality.

Umut, I have wondered the same thing about viscosity of inks and how easily one could just inject them into a normal printer cartridge. For starters, not being limited to a CMY pallette would be advantageous, and if one could find the original autochrome dyes, then all the better.

Mustafa Umut Sarac · Oct 26, 2010

Chris ,

Original autochrome dyes are herebelow. They are still in use . So I think they are manufactured for easy flow and easy to printing machine - like heidelberg- use or other technical use.
I will try to find their CMYK match and it would be easier at first cheapest tryout.
I found acid yellow is manufactured for inkjet printers. Much water and some additives and dye makes the printer ink. But I have to look their concentration with starch grains.
If there is water in formula , I think two printer brands are also suitable for use.
I will list their below listed chemicals prices in few hours.

Acid Yellow 23 CI 19140
Basic Green 1 CI 42025
Acid Blue 3 CI 42051
Basic Violet 3 CI 42535
Acid Red 51 CI 45430
Acid Red 54 or 94 CI 45440

Best ,

Mustafa Umut Sarac

Istanbul

Athiril · Oct 26, 2010

holmburgers said:
Did you experiment with just red, green and blue before going to this 5 color system? What was the result with magenta that led you to not use it?

In reading about the history of screen plates there have been examples of people utilizing rainbow colored screens and the like, all in the hopes of more real color. But it actually serves to desaturate the colors, since it's an additive system and subtractive-complementaries are wider-band than red, green & blue. But, perhaps there are other advantages (like speed) and as they say, the proof is in the pudding and your example looks great! So whose to say...

And yes, I'm afraid Athiril, that if you're truly "painting" on the starch then it'll be a total failure. Not to say you shouldn't try and see for yourself.

But think about it; imagine a picture of a banana. The yellow reflected light from it will go thru the green and red elements in some proportion and be mostly blocked by the blue. Consequently, upon reversal processing (for example's sake, negative processing gets same result but... well you know) the clearest portion will be behind the green, with a gray behind the red and hi-density behind the blue. These are called tristimulus values; the relative luminosity of RGB in an additive system.. exactly like a TV. If this condition is not met, your color will be meaningless/no relation to reality.

Umut, I have wondered the same thing about viscosity of inks and how easily one could just inject them into a normal printer cartridge. For starters, not being limited to a CMY pallette would be advantageous, and if one could find the original autochrome dyes, then all the better.

A thin scraping of some kind.

The colour would be wrong and bizarre with a misaligned screen, yes.

But lets take a bayer sensor screen pattern for example.. evenly distributed more or less, mine is not as neat and structured, but still should be evenly distributed given an even flat layer atop the film.

I can create a screen of the same distribution in photoshop and adjust the size, and shift it to match, or take a scan of another screen and align it.

Another screen might not be dead on, but it should have the same colour grains distribution logically, so I cant see why it would need any more than simply shifting up/down and left/right.

holmburgers · Oct 26, 2010

I think you're right, I'm just going off the fact that you said "painted" on starches. If you used a raster/grid then using a different screen wouldn't be much of a problem; that's what Paget plates did. You shot with one screen and then switched to another for viewing/printing.

You mention scanning... this raises an interesting possibility. You could create a random/stochastic screen by painting on, and then scan this screen (or contact print it onto slide film for that matter) for printing out later; discarding the original. Registration would be theoretically possible, but practically difficult to reach precise alignment.

The thing is, even with a logical distribution, if alignment isn't dead-on then you're gonna get incredibly distracting moiré patterns. Like with my example, when I try to get them in registration it's like someone's shooting a psychadelic light on the scene. If I rotate the screen off-axis, the moiré goes wild!

Athiril · Oct 26, 2010

Alignment would be very easy post-scan, as you said, moire-patterns, even with a generated evenly distributed screen, as long as the size is right.

In any case, it's easy to shift things around pixel by pixel with a scanned screen, it should aready be at the correct size.

Stephen Frizza · Oct 27, 2010

This is a scan from an RGB screen over ERA 4x5 film. The test is a failure. Perhaps RGB screens will work on other films however my results from ERA 100 using a linear RGB screen just don't look as good. THIS IS A FAILURE.

Note : in my RGB screen the colour values of the RGB in the output file were diffrent to the values of my RGB in the RYGCB screen. Primarily using this method i think the addition of a yellow has significantly improved the screen

Stephen Frizza · Oct 27, 2010

My only advice for anyone wanting to get into this is A, Start by making easily separable DIGITAL Screens in a Linear Aray. Experiment with film types and experiment with the Tone of your Red green and Blue and if you want to venture down my track yellow and Cyan. perhaps in time if i experimented more I would find a combination of RGB and a film type which works well together and the Yellow and Cyan wont be relevant. From my own testing TMAX 100 and Tmax 400 using this method were disasters! though the bulk of my testing has been on ERA film simply because its been a cheap yet effective medium to experiment with. Also its base if very clear and the BMS when reversal processed has a good tone to it.

After perfecting linear (which I certainly haven't yet done and dont think i will) I would suggest moving onto slightly more complex RBG pattern on a digital
screen (such as a diagonal linear screen) then onto something more complex before delving into a complete randomization of the screen pattern.

oh also get a colour chart, a neutral wall and some very colourful items to use as your tests.

holmburgers · Oct 27, 2010

It's very interesting that the RGB screen was such a failure. I can't reason why...

Thanks for posting your examples, they are a great benchmark to set (the first example that is).

Mustafa Umut Sarac · Oct 27, 2010

Stephen , Chris ,

I liked your failure most. Look at the colors at the chart , how many times a person get these colors from his pictures ? If my autochrome will be the same with digital perfect picture , Why would I invest on it. Your failure says that there can be thousands of rare colors will be produced with these screens.

It is what I wanted most. It has the Belgian , French cartoons colors , not picture perfect Tin Tin.

Find Adele Blanc Sac comics at internet , dark classy colors and phosphore colors will always inspire me.

I will reread the posts and investigate the reasons of these colors.

Stephen , can you prepare a 8x10 filter and post to here. If the file is too big , send me via email and I will post from my blog.

Umut

Photo Engineer · Oct 27, 2010

From my POV Steve, the R/G/B example looks a bit dark. I think that a bit more exposure would clean it up quite a bit.

PE

Mustafa Umut Sarac · Oct 27, 2010

Scanners tends to give such a grain when the film , image is dark.

holmburgers · Oct 27, 2010

Umut,

I like your outlook on these colors. You're right; why should we hope to reproduce nature perfectly? Although that is a goal of mine, you are bold to say that this is not the goal and I'm inclined to agree!

Deviations from reality are inherently more interesting and the degree to which they deviate can be what sets one process apart from another.

holmburgers · Oct 27, 2010

I've been thinking about how to secure my slide-film screen to my b&w film in close, optical contact.

How could one adhere the two films together before exposure and then release them either with a solvent or water for processing?

Kodak film cement (probably not)? Canada balsam? Water???

Two wet films will most certainly stick to each other, and quite well. And assuming I could soak the two to disconnect them, would there be any detrimental effect to the b&w emulsion by getting it wet before exposure?

Furthermore, once it's processed, is there a glue that would be suitable for registration and final display? The most important condition would be that it is exceptionally thin, and that it doesn't dry instantly to allow for time to gain perfect registration. I know there are many glues, but it can't be too tacky to begin with. Though, if I get my pin-registration down this might not be a problem, which was jeoparized on my first trial... I used the punch to re-register and in doing so made new cuts which slightly enlarged the holes. If I get some non-cutting pins or dowels, that should work better.

Photo Engineer · Oct 27, 2010

To quote the immortal bard.

"Aye, there's the rub".

Good luck on this. I think it could be mounted just behind the focal plane shutter and the film pressure plate would keep them in contact.

PE

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

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