Turning negative film to positive without liquids

radiant · Jul 12, 2020

Yesterday I was hanging some 120 size film to dry in our sauna and I noticed strange effect. The sauna was really dim and light was coming in from small window. The hazy light lit the negative so that I could see the positive image! It was a bit amazing effect.

I thought this is so cool and I need to make an apparat to reproduce this everywhere. So I did. I milled a box, covered the inside so that it doesn't reflect and prototyped the lightning.

Here is the result:

Here is s a shot of the box without inside light so you can see that it is really a negative

Is this an old idea or has someone made such displays?

Do you have any ideas how to "intensify" the image so that less light would be needed (deeper blacks)? I guess overdevelopment increases fog?

ic-racer · Jul 12, 2020

Do you have any ideas how to "intensify" the image

Rather than using a clear plastic base, coat a plate of black metal, or 'tin' with the emulsion, prior to exposure. It can remain wet during exposure...

MattKing · Jul 12, 2020

vedostuu said:
Is this an old idea or has someone made such displays?

This is essentially how ambrotypes are viewed.
Is 1854 old enough?

radiant · Jul 13, 2020

ic-racer said:
Rather than using a clear plastic base, coat a plate of black metal, or 'tin' with the emulsion, prior to exposure. It can remain wet during exposure...

Haha, very funny.

MattKing said:
This is essentially how ambrotypes are viewed.
Is 1854 old enough?

So you are saying ambrotypes are backlit with light?

MattKing · Jul 13, 2020

vedostuu said:
So you are saying ambrotypes are backlit with light?

No - they have a black backing, so the light ambient coming from the front is reflected off the negative image, and absorbed by the backing, yielding a positive image.

radiant · Jul 13, 2020

MattKing said:
No - they have a black backing, so the light ambient coming from the front is reflected off the negative image, and absorbed by the backing, yielding a positive image.

So a different method then

MattKing · Jul 13, 2020

vedostuu said:
So a different method then

No, I think what you are doing is essentially the same - you are just supplying the light.

radiant · Jul 13, 2020

MattKing said:
No, I think what you are doing is essentially the same - you are just supplying the light.

Ok, seems I maybe I asked the question too broadly. Sorry about that. I think however there is just a tiny and slight difference between ambrotype and backlit film negative somwehere in the process

Let me ask again with refined question:
Is this an old idea or has someone made such displays using negative film?

Nodda Duma · Jul 13, 2020

The physical process by which the negative appears as a positive is the same: Light at certain incident angles are directed towards the eye by the silver halide grains rather than a light directly behind the negative being blocked and rendering highlights as dark. It’s a cool effect. Your viewing box limits the incident angles of light to show off this effect. What responders are trying to tell you is that placing a black surface immediately behind the emulsion does the same: Shows off this effect by limiting light hitting the negative to grazing angles which reflect off the silver grains towards the viewer.

If the silver grains are small enough, then they can also record wavefront / phase information and reproduce color in a viewing box similar to yours. This is known as the Lippmann plate, and Nick Brandredth at the GEM has been making viewing boxes lately for his Lippmanns.

I see it often in dry plates, especially when I screw up the metering and underexpose.

You may find that thin or underexposed negatives also enhance the effect.

So the idea is not new, but that should by no means detract from your creativity in coming up with a tangible integrated product to show the effect. I think it’s great.

cheers,
Jason

radiant · Jul 13, 2020

Nodda Duma said:
What responders are trying to tell you is that placing a black surface immediately behind the emulsion does the same: Shows off this effect by limiting light hitting the negative to grazing angles which reflect off the silver grains towards the viewer.

It maybe could if there was really low amount of fog / high amount of silver? Looking at negative against black background does not bring the safe effect. You can actually see it on the other photo where the background illumination is not powered up. It just looks like a negative.

If you have any ideas how to produce the same effect with film negative and without any background light please show how it is done!

Donald Qualls · Jul 13, 2020

Any negative film can be viewed as a positive if front lighted against a dark background. I do it routinely in my darkroom, though I don't attempt to evaluate negatives on that basis (to look right as a positive, the film would need to be overexposed by at least a couple stops). As noted above, emulsion coated directly on a black surface (either blackened metal, or black glass) was used for direct positives from the end of the Daguerreotype era until the 1930s (by traveling photographer) and up to the present on a specialist artisan level. However, if you take a piece of black velvet and lay a regular negative on it, emulsion up, you will see a positive image, at least at certain angles of light and view.

What seems different here is that you've found a scatternig angle for back lighting that gives the same effect. I'm pretty sure I've seen this on hanging film as well, but it's easier to see and, in my limited experience, brighter and contrastier with front light against a very black background.

radiant · Jul 13, 2020

Donald Qualls said:
However, if you take a piece of black velvet and lay a regular negative on it, emulsion up, you will see a positive image, at least at certain angles of light and view.

I tried this. Yes, kind of. Not quite. The effect was really faint in my opinion and the silver on emulsion makes some strange effect where part is negative and part positive. I used black velvet and tested different lightning.

I'm still interested have anyone seen such way of displaying image with negative film? Why I am asking is that if I could learn something from others who have done the same in terms of how they have implemented the backlight and how they have increased the contrast. I will probably try the underdeveloping method but that seems counter-intuitive because I would guess one needs more density? Of course underdeveloping reduces fog but the negatives I used were really low fog compared to others negatives I have.

warden · Jul 13, 2020

vedostuu said:
Here is the result:

Outstanding! And I like that portrait as well.

Donald Qualls · Jul 13, 2020

What I said was that you need to overexpose the negative, not underdevelop it. In fact, you want a high contrast index, so you're not after a Zone System "overexpose and underdevelop", you're after a bulletproof alt-process type negaive.

removed account4 · Jul 13, 2020

jawarden said:
Outstanding! And I like that portrait as well.

+1.

ive done similar things but never made viewers just looked at my grossly underexposed film and said cool!
I like your way and presentation much better.
Can’t wait to see you do this with a big negative !

radiant · Jul 13, 2020

Donald Qualls said:
What I said was that you need to overexpose the negative, not underdevelop it. In fact, you want a high contrast index, so you're not after a Zone System "overexpose and underdevelop", you're after a bulletproof alt-process type negaive.

Ah, true. Of course. I must try this! Also I have an idea for better light distribution and how to enhance the light reflections.

Thank you @jawarden and @jnantz - of course I would be keen to try this on 5x7" but I would need to find a film with low fog and to be in some kind of reasonable price range ..

Donald Qualls · Jul 13, 2020

The least expensive large format you're likely to find (other than Ortho Lith or similar) is Arista .EDU Ultra, which is rebranded Fomapan. I processed some (in 120) just yesterday, and the fog level seems really low. I've processed this and the same film boxed as Fomapan in Xtol, Parodinal, Caffenol, and D-23 -- it's good in all of them.

radiant · Jul 13, 2020

Donald Qualls said:
The least expensive large format you're likely to find (other than Ortho Lith or similar) is Arista .EDU Ultra, which is rebranded Fomapan. I processed some (in 120) just yesterday, and the fog level seems really low. I've processed this and the same film boxed as Fomapan in Xtol, Parodinal, Caffenol, and D-23 -- it's good in all of them.

I also processed Foma 100 in Xtol 1+1 20degC and the fog is horrible for this use. Oh how I wish Foma could do it because those films are cheap for large format photography.

foc · Jul 13, 2020

You can get a similar effect with a C41 neg that has NOT been bleached correctly.

AgX · Jul 13, 2020

As others already said, such is well known and the base even of photographic processes. And I am very, very surprised that the OP not discovered himself this effect much earlier. I discovered it when I proceessed my very first films. Maybe for him it was that wood and trees effect that protracted such discovery.

There was even a commercial lighting device employing this effect to view a standard negative as positive

Donald Qualls · Jul 13, 2020

vedostuu said:
I also processed Foma 100 in Xtol 1+1 20degC and the fog is horrible for this use. Oh how I wish Foma could do it because those films are cheap for large format photography.

I've only done a couple rolls of Foma/Ultra 100 in XTOL (partially seasoned replenished stock), but the rolls I did yesterday have some of the lowest fog I've seen -- and that's saying something, coming from an old HC-110 user. I don't currently have any in-date 4x5 Ultra 100, and I don't think it's reasonable to compare fog on film that's been stored at room temperature for more than a decade (and even so, I haven't processed the recent exposures yet).

radiant · Jul 14, 2020

Donald Qualls said:
I've only done a couple rolls of Foma/Ultra 100 in XTOL (partially seasoned replenished stock), but the rolls I did yesterday have some of the lowest fog I've seen -- and that's saying something, coming from an old HC-110 user. I don't currently have any in-date 4x5 Ultra 100, and I don't think it's reasonable to compare fog on film that's been stored at room temperature for more than a decade (and even so, I haven't processed the recent exposures yet).

Donald have you got any other negatives with low fog to compare? I mean I have seen low fog negatives before but the negatives I used here were totally clear, I mean really clear. Those were shot against black backdrop with studio flashes so I wonder if that makes any difference. I need to check my other Foma studio negatives which were shot similar way to see if that is the case.

Getting lower fog is quite intresting effect to achieve since it is vital part for this kind of presentation. I'm totally curious how can two such almost similar development methods result in such different fog amount.

koraks · Jul 14, 2020

vedostuu said:
I would be keen to try this on 5x7" but I would need to find a film with low fog and to be in some kind of reasonable price range ..

This is one of those (rare) cases where xray film may be a good option. Since it lacks a topcoat (or only has a very thin one), it very readily exhibits this 'positive' effect. The only (major) drawback is its blue base, of course.

bernard_L · Jul 14, 2020

Donald Qualls said:
to look right as a positive, the film would need to be overexposed by at least a couple stops

?? In my experience, the effect is most readily visible for under-exposed frames. I just checked with a normally exposed film, viewed against a black background, and illuminated at a slant angle: the emulsion's silver appears a an almost uniform milky white, and only the original scene's deep shadows (low negative density) let me see the black background. That is a simple experiment anyone can repeat.

koraks · Jul 14, 2020

bernard_L said:
?? In my experience, the effect is most readily visible for under-exposed frames. I just checked with a normally exposed film, viewed against a black background, and illuminated at a slant angle: the emulsion's silver appears a an almost uniform milky white, and only the original scene's deep shadows (low negative density) let me see the black background. That is a simple experiment anyone can repeat.

The 'positive' effect works best on very thin images - i.e. negatives that may print OK on grade 5 or even not at all. So that means that in any case, development needs to be curtailed, but to get good detail in the shadows, a good strategy is actually to overexpose. Of course, if you get one of these negatives by accident, it will generally be as a result of having underexposed (significantly) and then normally developed, which results in the highlights showing up OK, but shadows remaining entirely open.

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