Autochromes...

You could do preliminary experiments under the enlarger duping color slides to prove the process. Then after that finding a 4x5 camera shouldn't be much of a problem. I would think sheet film of some sort would be much better than roll film for this kind of handling.

Wow - the enlarger with color slides is quite a good idea. I for some reason did not think of that. It would eliminate many factors, including the camera and lighting, and would allow me to use a light source that I know and have worked with. Thinking about it, that would also let me do test strips to test exposure times.

Exposure tines would probably be manageable under the enlarger as well, as I'd probably be using ISO 100 film / 40x reduction in speed for the screen = ISO 2.5; depending on the amount of light and hte slide, exposures would be, maybe a second or two....

Due to my dislike of current color materials, I have actually never shot color slides, but I do have some old Kodachrome slides (of unknown origin) hanging around, which are useable enough. If those don't work, I can always shoot some, use color negatives (maybe?) or use my "Old MacDonald Had a Farm" filmstrip (no idea where it came from - this stuff just shows up...)

I'll send the new additive mask that I made through the laser printer tomorrow and get an order for some sheet film into J&C and see how this turns out.

Once again, thanks for all of the ideas, everyone.

Here are some thoughts for you to consider:

1. Any film with a rem-jet back and that is pancrhomatic may have this backing removed so that it can be exposed through the base. This might work out for you. Some come in sizes up through 70mm IIRC.

2. Hand coating of a monolayer of material is doable. I can do this right now in 8 different coating gap widths. I am working on a method to have continuously variable gap widths so that the possibilities can be expanded quite a bit.

I just finished coating 12 sheets of paper with a gap of 5 mil, and could have coated as thin as 2 mil. With my new equipment I could go less than that and achive what you want. Quality approaches that of commercial coatings if you adjust surfactant and viscosity appropriately.

PE

Laser printer won't work at all well for printing directly onto gelatin -- the toner is a thermoplastic material, and will be impervious to water after fusing; as well, the fuser is more than hot enough to both fog and soften even the superhard emulsions on Kodak and Ilford films (and never mind the softer emulsions on Pro 100, Efke, etc.). For a registered overlay, it might or might not work, depending on how transparent the toner is (and this can be adjusted to some extent, at least on the B&W laser printers I'm familiar with; there's a toner control that's supposed to be adjusted to the lowest level that gives good black).

In making an image to print for a screen, regardless of method, you'll want to ensure that the image has a resolution that matches that of the print method used -- that is, you won't want to make the image at 1440 ppi if your printer can only do 300 ppi; doing so would make individual pixels with more than one color, if not just gray, resulting in loss of both saturation and speed.

All antihalation dyes are water soluble, though many come out readily only in an alkaline solution (they're in a gelatin coating, either on the base side of the film, or under the sensitive layer(s) on the emulsion side). Removing the AH with a bath, however, would also wash out the sensitizing and panchromatizing dyes. That's not a problem during development, because they've already served their purpose (of ensuring the silver halide is correctly exposed), but film that gets wet before exposure suffers major changes of character -- loss of speed, and sometimes loss of spectral range as well.

The original Lumiere Autochromes were coated by spreading the starch onto a precoated glue layer. The method, as I recall it from my reading, was to broadcast the mixed starch (all three colors, neutral color ratio) onto a thin layer of glue, remove the grains that weren't stuck, and then roll the plate (for a start, a braying roller would work) to press the grains down into the glue -- somewhere in there, the black matrix was applied as well. You need an excess of dyed starch, and a minimum of glue, in order to get a monolayer; the glue layer should be thinner than the diameter of a single starch grain, ideally less than half if not the same as the black matrix. Then, when you apply the black matrix layer and roll or press it, the matrix can squeeze into the spaces between starch grains.

It seems to me we had once discussed (on a Yahoo group?) using predyed gelatin granules or flakes as the dye grains; pressing those into a black dyed gelatin might allow forming a water permeable filter layer on existing film, with black matrix in place.

htmlguru4242 said:

I have considered the Maco "Aura" Film, and it at first seemed like a good idea.

There are three problems, however:
1.) The base is not clear

Click to expand...

It is. That's what the "c" stands for.

htmlguru4242 said:

2.) The film's sensitivity is high in the UV / Blue / Yellow, and again in the Red / IR area. There is very little yellow green, green and orange sensitivity.

Click to expand...

This film is panchromatic with extendd red sensitivity. There is no drop in sensitivity to orange/yellow/green. See http://www.mahn.net/TA820ce.pdf

htmlguru4242 said:

3.) The film is rather expensive, as I can only find it in sheet film form. It is about $65 for 25 4x5 sheets; $2.60 a sheet. This is an awful lot for early experiments. In addition, there is the problem that I do not have a 4x5 camera (other than Pinhole), which I think would be adding an unneeded factor to this.

If, once I figure out how to produce the screen, perhaps I could buy a sheet or two of this film off of someone for experiments...

Click to expand...

True, it's expensive. I have some sheets I don't think I'm going to use - the lack of anti-halation layer seems to me to be a waste on LF.

Oh - oops, that would have been my mistake. I remember reading that the base in Maco IR820c was not clear, but I'm probalby mistaken. As to the spectral senstivity, I looked back at the website I was using and realized that I was looking at Kodak HIE ... Wow I sounded like an iidiot there...

But in that case, Maco IR820 Aura seems like a perfect chioce, at least initially...

And to Donald, when I was talking about was a removeable screen on the laser printer - wanted to see if I could shoot and re-register the screen after development.

And, If using IR820c, the screen can be glued to the back of the film, and it can be exposed through the base.

Any suggestions about how to coat the starch on a monolayer?

Donald, the rem-jet backing as used on some films can be removed easily without harming the emulsion layer at all. A sponge damp with dilute alkali, rubbed on the back of a sheet film will remove it entirely. Then, a damp sponge with water will remove excess alkali and residual rem-jet leaving a clear film that can be exposed through the base.

HTML, by making up a 1:1 suspension of starch in gelatin and coating the mixture at about 100 mg/ft2 of melted gelatin at 10% will give about 1 micron dry (IIRC - I've forgotten some of this so I have to go through a lot of calculations). So, coat at 10 microns with 1 micron particles and you will have a monolayer when it dries down.

If I have it wrong here, it is merely a matter of correcting my old mental math and then doing a few hand coatings. As Donald says, rolling was part of the process to smooth out the starch grains as well.

PE

Ok - it's good to know that teh anti-halation backing can be removed by water on some films - I didn't realize that anything other than Kodachrome and some movie films used rem-jet anymore.

Which films have said rem-jet backing? I'm assuming that its those that have a "water soluable" anti halation backing?

I've printed out a mask that can be used easily for this if it were to be glued to the back of a clear base film. I'll try this first, and then after, try actually making a starch mask.

I'd really like to know which films have this layer, so I can order some and experiment this weekend. By any chance, J&C sheet film or Arista EDU (the cheapest sheet film out there) have this removable anti-halo layer?

Would Kodachrome be a candidate? If I recall the rem-jet is on the backside, and could be removed and then it could be processed like a regular black and white film. Or would it be easier to leave it inplace, and coat the colour particles on the emulsion and then process in B&W chemistry?

Well, I guess that you Could use Kodachrome, or any color film, for that Matter, but it would be pointless and difficult. In addition, it is quite expensive (B&H sells a 36 exposure 35mm roll for $6.49), and I'm not sure how long Kodak is going to continue its manufacture. Also, the point here is to use black and white film.

The particles could possible be coated onto the emulsion side, but there are two problems. First is finding a way to keep the emulsion permiable by water, as the developer, stop, bleach, fix, etc. need to penetrate it during processing. It would be difficult to coat particles onto it and still satisfy this. The one possiblility is, as Donald Qualls suggested, to use an inkjet printer with modified inks to print onto the emulsion.

To keep the process somewhat authentic, my plan is as follows:
1. Clear anti-halo backing from film in darkroom, using a sponge soaked in water and an alkaline compound (maybe NaOH?)
2. Create, on a very thin sheet of plastic, a mask of dyed potato starch (or gelatine, or plastic, etc.) particles, which will be glued to the mask.
3. Use a roller to flatten out the particles, distribute them more evenly, and allow them to adhere better to the glue.
4. Once these have dried, apply some type of varnish over the plastic, in order to keep the particle screen protected from air, prying fingers and developing agents. This will be done in the light
5. Attach the screen with some type of clear glue (not sure what to use) to the base of the film. Perhaps roll lightly. This is done in the darkroom once again.
6. Once this has dried, expose through the base and screen in a camera or under an enlarger (the film, by this point may be slow enough for this).
7. Reversal process by the standard B&W reversal process.
8. View the final transparency through a white light source.


It's that easy )

You don't need NaOH to remove rem-jet, sodium carbonate will do nicely (and is MUCH safer to use in the dark). You will need some precaution against wetting the emulsion side of the film, as any water on that side will remove or redistribute sensitizing dyes and give unevenness (even as little as condensation from thawing film refrozen after opening can do so).

PE's method of making a gelatin carried monolayer looks very promising -- the gelatin can be dyed with a non-soluble dye (like the marker inks) to provide the black matrix, though you'd probably have to do the rolling at a very carefully chosen point in the cooling process -- however, that'd be much simpler when you do that part of the work in the light.

Bad news is, I don't know of any large format film with remjet. The "water soluble antihalation" you refer to is the opposite -- rem-jet is NOT water soluble, comes off only with alkali and does so in the form of a suspension of carbon black particles or veils of binder. However, that raises the question of whether it would be possible to roll dye granules directly into softened remjet -- likely a moot point, since I'm not aware of any B&W film that carries a rem-jet (perhaps some 35 mm B&W cine stocks), and removing a soluble antihalation is likely to be much more difficult without damaging the emulsion.

The IR820c Aura is likely to be the best bet for a first experiment with an adhered, base-side filter layer. It's already on a clear base and free of antihalation. J&C Photo has it in 4x5, I think, as well as 8x10; it's a couple bucks a sheet for 4x5, but comes in very small boxes (like 10 sheets).

Hmm.... I don't see Aura 820c in 10 sheets, only 25, which costs $64. IT's probably worth it, though.

On another note, are there any roll films (specifically 120) with rem-jet?

Many motion B&W motion picture films use rem-jet, which is removed by dilute carbonate solution.

You can get these films in sizes up through 70mm x 100 ft rolls IIRC.

Do not use Kodachrome, as the yellow filter layer will prevent exposure of the top layer (exposing through the base) and will leave a dark yellow cast in the finished negative.

Another way to get a suspension of dye in gelatin at the right particle size might be by using a colloid mill to create a 'dispersion' (really an emulsion) of the particles in gelatin. The problem that I see is that the droplets might merge when you get it concentrated enough. This is a constant problem when it comes to dispersing liquids in gelatin at high concentration.

PE

What is this "colloid mill" that you mention to disperse particles in the gelatine?

Also, I was thinking of motion picture film as well, but I'm not sure where to get 70mm. Do you know who would sell that?

A colloid mill (such as a Polytron) is a device that disperses oils in water or water in oils as tiny (0.1 - 1.0 micron) droplets by high speed shear force coupled with high speed and mixing blades. It is like a super blender for industrial grade fine particle work. It is used to disperse couplers in color film in that tiny size range for color imaging and works just fine with resins and things like starch grains. You can set the gap of the mill to yield the particle size you wish, and so theoretically you could grind your starch down to 0.1 micron particles. It does generate a lot of heat doing this so they are generally water cooled and have a huge motor to drive them at the RPM and with the force needed to do their job.

70mm Motion Picture film or similar is probably sold by Calumet, B&H photo, Adorama, etc. IDK for sure. You would want to have a negative stock not a reversal stock, and you would need it without sound track.

PE

I'm still searching for clear - bas, non anti-halation films, but I'm thinking that Maco Aura is the best choice. I only have one other question. Do microfilms have an anti-halation bakcing or an easily removeable one?I know that they are available, and which the right developers, can be useable for pictoral work.

Keep an eye on this thread:
(there was a url link here which no longer exists)

An answer may arrive.


Back to lurking...

That's good -exactly what I'm looking for.

And there's no reason why you HAVE TO lurk, mrcallow. If you have any ideas or questions about the discussion, feel free to join in.

I want you to succeed so that at a minimum i can see the product and at best to use the product. As I mentioned I am out of my water, when I have anything of value to add I will.

htmlguru4242 said:

Do microfilms have an anti-halation bakcing or an easily removeable one?I know that they are available, and which the right developers, can be useable for pictoral work.

Click to expand...

The microfilms I've used (Kodak Imagelink HQ and Agfa Copex Rapid) have a soluble antihalation, same as Tri-X or TMY -- it's dark purple on the Copex Rapid I've been using lately in my Minolta 16 cameras. OTOH, I'm not certain the sheet forms of these films have the same backing; I'd bet J&C Photo, who sell the Imagelink recut to 4x5 from micorfiche size, could tell you what kind of antihalation it has, if any (and they'd be very happy to sell you some, but it's more expensive than the IR820c Aura -- though with much finer grain).

Lasty night, I experimented with some dyes, in order to possibly create a mask for this. I finally checked my potato starch, which has finally settled out of the solution in which i had it. A whole potato yeilded barely a half gram of starch. What I have is proabably enough to cover a 5x5 cm area with a monolayer. This is not enough for my experimentation, athough it is remarkably round, evenly sized and clear.

I also tried dyeing gelatine, as I have a lot of it, and it should readily accept dyes.

I placed gelatine in an a mixture of acetone and isopropyl alcohol, which contained dyes, both from food dyes and Sharpie markers. The solution was quite dark, and instantly dyed the gelatine. As I expected, the gelatine did not dissolve into the acetone; rather, it clumped up.

After removal from the acetone, the gelatine dried (slowly). I attempted to add heat in order to speed up the drying, but this caused hte gelatine to melt into a solid, gooey mass. It has since solidified into a dark blue mass (blue was the color I was testing). I may be able to grind it into a fine powder; we'll see.

Powdered rice starch is recommended in some old text books for the best use in gelatin. Cornstarch is also suggested. Formulas exist for making this type of starch in gelatin, as it is used as the matting agent in matte papers.

I have a series of suggestions.

1. Dye the starch, not the gelatin.

2. Dry it and make a fluffy colored powder from it. (if you can wash it well and decant most of the excess water, you can probably use it without drying)

3. Make up gelatin to 10% (wt/wt) and add a surfactant to it such as Photo flo 200 or the like at about 1 - 5 drops / 100 ml of 10% gelatin.

4. Add the dry starch with vigorous stirring to the gelatin mixture but don't whip in any air. The final starch concentration should be also 10% (wt/wt).

5. Coat that mixture on a clear support at about 100 mg of solution / dm square. That should dry down to about 1 - 10 microns.

(if the dry dyed starch or damp starch is too coarse, give it a whirl in the blender, but don't let it heat up or it will become sticky)

This coating is unhardened. If you wish to harden it, to check out the fastness of the dye in starch, then add to each 100 ml of the gel/starch/dye solution about 30 drops of 10% glyoxal before you coat it.

PE

I realize that dyeing the gelatine is not a good idea if it is being used as a gelatine coating. However, I was trying to use gelatine grains instead of starch grains. Because they will be put into some type of varnish / glue to be coated onto the back of a clear - base , non anti-halation film, they won't be exposed to water. However, I find the idea of using starch quite a bit more useable, as dyeing it might be easier. My only question is where I would find rice starch, as it doesn't seem to be around anywhere. Also, I didn't know if cornstarch was transparent enough to allow any light to pass through it in order to expose the film, but its worth a try. This way, with teh gelatine, I can coat onto the front of the film as originally planned. I'll try this tonight.

Gelatin is unsatisfactory due to its inherent properties. It cannot be ground up into small dry particles easily. It is too tacky and melts during the grinding process as the melting point is too low.

Starch is far better.

Colored oil droplets dispersed in gelatin might be even better as I mentioned above.

PE

I'm working on getting potato starch, as I want to try that out.

With the sharpie dyes that i was working with, corn starch does not dry very well. I'll see what I can do to impove this. Perhaps dyeing the starch again, after it dries, will allow it to become slightly darker. I'll also look for other dyes. Does anyone have any suggestions as to dye type?