Film Negative Exhibiting A Wet Plate/Ambrotype Effect?

[jcoldslabs]

I took the B&W negative you see below, backed it with black construction paper and scanned it as a positive in reflective (opaque) mode. What you see is a straight color scan with only some dust removal and minimal contrast adjustments. The color is native to the scan and so is the 'wet plate' reversal effect.

Many of the negatives I've shot with this film seem to have this look when scanned this way. No other film I have ever shot has done this. I accidentally underexposed a roll of film by three stops one time that had somewhat of a reversed positive look when held at an angle against a dark background, but this negative is not underexposed--at least not grossly--as it scans just fine as a negative in transparency mode.

The film is Kodak's Electron Image Film (SO-163) which was designed to be used in electron microscopes. It is orthochromatic and appears to have no anti-halation dyes (an undeveloped sheet is uniformly off-white on both sides). I rate it around EI 20 and develop in HC-110 1:79 for four minutes.

Does anyone know what might account for this? I'm stumped.




Jonathan

[Jody_S]

I don't know, but I have a box of the stuff and I keep meaning to try it. I like the look you're getting with this.

[Jim Noel]

It is under-exposed. Years ago I did this on purpose so could better preview negatives as positives w/o making proof sheets.

[jcoldslabs]

I don't know, but I have a box of the stuff and I keep meaning to try it. I like the look you're getting with this.

Jody,

Give it a go! The 4" wide sheets slide sideways into regular 4x5 holders just fine. And you can work under a red safe light so you can see what you're doing. I just apply a small piece of tape to one edge to keep the film centered (a small square of double stick tape on the back would work, too) and mark my ground glass accordingly.

It is under-exposed. Years ago I did this on purpose so could better preview negatives as positives w/o making proof sheets.

Jim,

I understand that Ambrotypes get their positive look from being underexposed and underdeveloped, but I have been exposing and developing this film during testing to achieve detailed shadows and restrained highlights. If it is underexposed it isn't by much (see below). I have, however, had to use a dilute developer for a short time to keep the highlights from blowing out since this stuff acts somewhat like Tech Pan (but without the red sensitivity). Maybe underdevelopment is the culprit?

Here is this same negative (cropped a bit) scanned as a transparency and inverted. I have a number of other negatives shot on this film with good shadows and highlights that also exhibit this effect which is why I'm puzzled. Regardless of the cause I think I'll scan these negatives in this new manner going forward since I really like the look.




Jonathan

[jcoldslabs]

For reference here's another negative scanned both ways. My flatbed is on the fritz; I apologize for the noisy positive scan.




Jonathan

[Jody_S]

Jody,

Give it a go! The 4" wide sheets slide sideways into regular 4x5 holders just fine. And you can work under a red safe light so you can see what you're doing. I just apply a small piece of tape to one edge to keep the film centered (a small square of double stick tape on the back would work, too) and mark my ground glass accordingly.






Jonathan

Yes, I've been following your progress with some interest. I have, I think, 200 shts of it. A box is 250, 5 packages of 50? So my box is missing one package. I'm waiting for you to get it exactly right and post your conclusions....

Seriously, I've been experimenting with imagesetting infrared film for the last year thereabouts, and as much as I've learned about developing to tame contrast, I'm starting to think that I will simply never be able to get a full tonal range from this film in real life (outdoor) situations. So I'm taking a break and shooting some of my 300-400 shts of expired 'normal' 5x7 film. I'm even experimenting with color this week, as I had a dozen shts of Vericolor HC in 8x10 and a small kit of C-41 processing chemicals. I'm hoping to develop my first color in 30 years over the week-end. I'm not expecting much because Vericolor never was very good expired, it's often completely unusable with large color shifts around the edges of sheets. But I won't know until I try.

[jcoldslabs]

I got the same effect again tonight. The first image below is the negative after scanning and Photoshop processing, the second is how the same negative looked in the wash tray. Still not sure of the exact cause since this is not underexposed. There is plenty of highlight density, although it could have used more development for extra 'punch'. For reference, I am now tray developing using HC-110 1:100 for four minutes. I am trying to develop by inspection under a red safe light, but I am still not sure what I'm looking for in order to pull the negative from the developer at the right moment.








Jonathan