Saving very thin negs - ideas?

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netzspannung

aka _basil
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Apr 19, 2005
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So, guys, I kinda made a mistake today

Developed Ilford Pan 400 in Rodinal 1:50 for 18 mins
The film was shot at something around 1600 ISO, so the negatives came out rather thin looking.
But when I look at them at a sharp angle, I can suddenly see the positive image with all the detail...
So do you think they might be saved? Scanning seems to be the best alternative... I also read about toning the negatives with sepia toner and also about some chromium intensifier formulas - wonder whether these would work?

Thanks
 
Waayyy back in the '80s when I was experimenting with stuff I tried using selenium (NOT sepia) toner to increase density of thin 4x5 negs. Chromium intensifier may work better, but I had not tried any.

Later,
Greg
 
An intensifier could be a good idea, but note, it gives the greatest effect the first time. Intensifying a negative twice does not produce as strong as a result.
 
DO NOT use Farmer's reducer as it will REDUCE negative density of which you have little. (It does increase contrast, but only when you have sufficient density to begin with.)
 
I've never used an intensifier on film, but I've been looking into this as well. I have a roll I screwed up on and ended up with thin results and details that I can barely see but that my scanner just can't pull out to my satisfaction.

Probably the safest (health and environmentally-speaking) intensifier is the sepia intensifier. It puportedly stinks to high-heaven. I've sepia toned prints before, so I imagine it probably smells pretty bad (rotten eggs!). But, it's better than working with the alternatives, stuff like mercury, and chromium intensifiers, which you probably will have to mix yourself. I don't know if they even sell that stuff as a package, or if you can buy (or would want to handle) the ingredients to create the intensifiers. Chemicals like: mercuric chloride, hydrochloric acid, or potassium dichromate. :eek:

I'm pretty sure Photographer's Formulary carries the sepia intensifier and you may still be able to get the Kodak silver intensifier.


:)
 
The same happened to me with C41: underdevelopment!
After scanning and using ALL Photoshop tricks I was able to produce very decent pictures.

Wim
 
I asked about this eons ago and someone mentioned something called 'darkfield reproduction' and there was a paper about it in german which babelfish did an ok job of but didn't seem to contain much detail IIRC.

Basically it amounts to viewing them off axis like you did. I too have been frustrated by the knowledge that the negative contains much much more information than printing or scanning can pull out. I've wondered if you could use the digital camera as slide copier thing and play with illumination angles to pull it off.
 
I've used Kodak Chromium Intensifier, years ago. It does increase density, proportional to the density already present. So there's an increase in contrast. I think it's more useful for underdevelopment problems than for underexposure, but it's bound to help somewhat. I don't know if Kodak still offers this product, but I see B&H is carrying this:
http://www.bhphotovideo.com/bnh/con...shs=chromium+intensifier&image.x=10&image.y=8
 
Chromium intensifier (try 10% potassium bichromate + 10 % sulphuric acid for starters) work by intensifying weak silver deposits. If your film is properly exposed but underdeveloped, you'd be able to intensify the faint negative image to produce a printable one. Though lacking in density, an underdeveloped but correctly exposed negative has enough silver to represent the information needed to create a proper positive, but lacks density for proper printing. The chromium needs this metallic silver to attach itself to, and by doing so, increases the density of the weak negative image.

On the other hand, an underexposed, underdeveloped negative is a double whammy of sorts. Underexposure means that there is already less developable silver to begin with. Push processing only increases the densities of the exposed areas, but it will not create densities in areas which did not receive exposure. Getting the underexposed film underdeveloped means that the needed printing densities are not achieved. Less silver means less areas for the chromium to stick to. As it is, only the brightest highlights would be present- and intensification will only work on these. The shadow areas will remain blank.

Farmer's reducer and 2-part sepia toners can be used for intensification. Take only the bleach part of the reducer or the sepia toner. Bleach the low-density negative to convert the developed silver back to silver halide. Then use the toner bath of the sepia toner (stinking rotten egg-scented sulphide) to tone the image brown. Underdeveloped but correctly-exposed negatives lack printing density- converting it to brown will make it more actinically opaque to printing papers. Again, this sort of procedure works only with properly exposed or moderately underexposed negatives.

One old trick I read about (never tried) it is to photograph the underexposed negative using a modified slide copier. The weak positive seen when the negative is observed at an angle is the target. The slide copier has to be modified so that light can strike the negative's emulsion surface at an angle to
make the 'positive' visible.

The intensifier with the strongest effect I've used is the very toxic Mercury Bichloride
bath. But the resulting intensified negatives are quite unstable.

Jay
 
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If you have detail in the shadows, the neg can be intensified and you will be ok. Without shadow detail, it will look like a pushed neg.

Victors` intensifier is what I use. It is better than chrome. Artcraft chemicals will sell the mercuric chloride. Mix out side and do not breath the stuff. It is toxic.

If you over intensify, the excess can be removed with plain hypo fix.

Google for the formula.
 
I tried this: I stacked a number 3, number 2.5, and Number 2 contrast filters (from top to bottom) into the filter tray of my enlarger, and set the aperture at f/16. I hoped the filters would cut the light dramatically, and give me more time to create a decent print. It worked okay. Some dodging, but it worked. Since the light hit the Number 3 filter first, this was the contrast level of the print, and not 7.5.

Basically, use the filters to cut the intensity of light passing through the thin negative. And keep notes.

Chris
canonetc
 
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