Effect of negative on Pt/Pd tone

Ian Leake · Apr 9, 2007

One thing that's always confused me with my Pt/Pd prints is the way the negative seems to change the print tone. I find the area outside the negative consistantly turns a rich middle brown, but the darkest area of the negative (i.e. clearest bits of film) have a much blacker tone with a visibly greater dmax.

My pet theory is that the film base (HP5+) filters out part of the UV spectrum that Pt/Pd is sensitive to. But has anyone else experienced this? And if so, do you have any better ideas as to why it happens?

Vaughn · Apr 9, 2007

My favorite pet theory is that without the negative base+fog, the borders get over-exposed and actually start to reverse (solarize).

Vaughn

Ian Leake · Apr 9, 2007

By jiminy I think you're right. I solarised a print yesterday when I was testing some gampi, and the effect was the same. But I hadn't put two plus two together yet. Sometimes I need someone to tell me the obvious before it becomes obvious to me Thanks.

TheFlyingCamera · Apr 9, 2007

The solarization effect is in part due to overexposure of the print. If your borders outside the film area are starting to solarize, you're overcooking your print. Time to look into adjusting your negative exposure/development regimen.

Vaughn · Apr 9, 2007

Ian Leake said:
By jiminy I think you're right....Sometimes I need someone to tell me the obvious before it becomes obvious to me Thanks.

LOL! I hope it is "obvious"! I am still waiting to hear from a real expert around here to give us the un-obvious "real" answer!

But as FC commented, it would be interesting to note how much exposure it takes to solarize the coated paper w/o a negative -- then try to keep one's exposure below that time....especially if one includes the border around the negative when displaying one's prints.

Vaughn

sanking · Apr 9, 2007

Ian Leake said:
One thing that's always confused me with my Pt/Pd prints is the way the negative seems to change the print tone. I find the area outside the negative consistantly turns a rich middle brown, but the darkest area of the negative (i.e. clearest bits of film) have a much blacker tone with a visibly greater dmax.

My pet theory is that the film base (HP5+) filters out part of the UV spectrum that Pt/Pd is sensitive to. But has anyone else experienced this? And if so, do you have any better ideas as to why it happens?

This is caused by solarization. lt happens when the negative has been develped to a DR that is to high for the specific paper/sensitizer. What happens is that by the time you expose long enough to bring in the highlights the very deepest shadows, and clear area outside of the image area, is over-exposed by 2-3 stops.

The cure is to develop your negatives to a density range that correponds to the exposure scale of your process. Or adjust the exposure scale of the process to match the negative DR.

Sandy King

Ian Leake · Apr 9, 2007

Thanks Sandy. It seems that every time I think I've cracked a bit of the process I discover something that throws everything in the air again Oh well, at least each time I get a little better at this

Kerik · Apr 9, 2007

If you're printing with pure palladium, adding some platinum to the mix will often reduce or eliminate the reversal effect.

Ian Leake · May 13, 2007

I thought it was worth updating this thread to help out anyone who reads it in the future. After some testing I've established to my satisfaction that while the symptom was solarisation, the cause was not over exposure to UV or over developing my film. I was in fact using too little pt/pd solution. Adding a few more drops has solved the problem AND improved the print quality Thanks for your help everyone.

Effect of negative on Pt/Pd tone

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