Salt printing weirdness.

[w.out]

I'm an amateur at darkroom stuff, having only been doing this for three months or so, since I inherited a darkroom and some old cameras. The last few weeks I've been trying salt printing - it's been really fun.

My first time trying it I made a basic salt solution, coated the paper, added the silver, and exposed three prints from the same transparency. All three worked (unexpectedly - thought I make a mess of it first time).

The weirdness: two of them came out negative, one of them came out as positive.

I have no idea how I managed this. Anyone help me out here?

 

[NedL]

I have no idea either. The only thing I can think of is that if you wash a salt print ( which removes the excess silver nitrate ) and then expose it to the sun, the silver chloride will become a sort of medium gray color. If the print was only weakly exposed to begin with, this might look something like a negative. But I've never seen anything that looked like a reversal myself.

 

[MattKing]

If it is possible to solarize a salt print, you may have accomplished that.
Solarization is the effect where gross over-exposure causes a reversal of tones.

 

[Prof_Pixel]

I wonder if you are seeing the bronzing that occurs with gross overexposure

 

[w.out]

I think it's the solarisation. The thing is, of the three I did, the one that came out positive was the least exposed.

I uploaded my hasty scan. I used a positive transparency (been doing anthotypes, so had a positive laying around), so the one on the left is a positive-of-a-positive, while the one on the right is the expected negative-of-a-positive. The left hand one is twenty minutes, the right hand one is thirty.

(I foolishly followed the exposure time of someone in Europe, forgetting that I'm in Melbourne, in summer, and we long since donated our ozone layer so others could have deodorant and refrigerators, so that "twenty minutes or more" exposure time should have been "five minutes, maybe less", which is what I use now. So these are burned to a crisp. Live and learn.)

 

[Prof_Pixel]

I still think its bronzing

 

[NedL]

I agree with Prof Pixel...looks like bronzing from overexposure.

 

[w.out]

Okay, so just to make sure I've understood you guys:

The overexposed areas are rusty brown, and the really overexposed areas are beyond a dark rust and moved into a kind of purple tone, giving the image on the left what looks like a positive, but actually isn't.

Whereas the image on the right is only normally overexposed, so it's a rusty brown on rustier browner.

Is that right?

(Thanks for your comments, by the way.)