Odd printout effect

[John Lockhart]

I was wondering if anyone can explain a printout effect I have been seeing in my prints lately. Follow the link below to see an example. I have been making kallitypes. The only change in my process is that I have been either:
a. Soaking the paper in acid. I did this with some Lana Aquarelle
b. Using some Arches Plantine

Just as a starting point is used the same exposure time I have been using for my other papers – eight minutes under four twenty watt black light bulbs. I expected this to be an experiment and for my exposure time to change a bit. I haven’t done a test strip yet.

However, at about six minutes I get this very rapid printout effect in the heavily exposed areas. I got this with both the acidified Lana and the Platine. After I develop the print it looks dead on. However, this level of blotchy printout just seems abnormal. It develops as small specks in the shadows. Again the prints are very close to what I expect once printed, but I just have this feeling that this is a sign of something wrong in my process. I would just think overexposure. However, the final prints look nearly dead on. Any ideas? Thanks for the help as I muddle my way through this.

http://www.flickr.com/photos/lockhart1969/4766040806/

[pschwart]

I was wondering if anyone can explain a printout effect I have been seeing in my prints lately. Follow the link below to see an example. I have been making kallitypes. The only change in my process is that I have been either:
a. Soaking the paper in acid. I did this with some Lana Aquarelle
b. Using some Arches Plantine

Just as a starting point is used the same exposure time I have been using for my other papers – eight minutes under four twenty watt black light bulbs. I expected this to be an experiment and for my exposure time to change a bit. I haven’t done a test strip yet.

However, at about six minutes I get this very rapid printout effect in the heavily exposed areas. I got this with both the acidified Lana and the Platine. After I develop the print it looks dead on. However, this level of blotchy printout just seems abnormal. It develops as small specks in the shadows. Again the prints are very close to what I expect once printed, but I just have this feeling that this is a sign of something wrong in my process. I would just think overexposure. However, the final prints look nearly dead on. Any ideas? Thanks for the help as I muddle my way through this.

http://www.flickr.com/photos/lockhart1969/4766040806/

Are the shadows solarized? If they are not and the final image looks good, then I don't see that you have a problem
If they are you should:
- print a step wedge and make sure you base exposure is correct!
- tone the prints -- this can help tame the solarization

[Loris Medici]

Perhaps acid processed paper or new platine paper is able to keep more moisture in the paper, compared to non acid processed paper and other paper(s) you were using before, hence the extra printout. Or, maybe your environment conditions changed recently and the air in your workplace is much more humid than before now (more humidity = more printout), or you have changed your method of drying the paper...

As Philip says; if the end results are OK then there's little to worry about.

Regards,
Loris.

[John Lockhart]

I see. The humidity is the likely cause. I said only the paper had changed however, following advice in another thread I started printing the paper less than 2 hours after I coat it. It feels noticeably moist compared to the paper I have let dry for many hours.

Do you know how the moisture would cause this effect?

Thanks again,

- John

[Marco B]

I see. The humidity is the likely cause. I said only the paper had changed however, following advice in another thread I started printing the paper less than 2 hours after I coat it. It feels noticeably moist compared to the paper I have let dry for many hours.

Do you know how the moisture would cause this effect?

Thanks again,

- John

Can't comment exactly to your case, but in order for any silver to be formed at all, electrons must be transferred from the iron ions in your sensitizer, to the silver to reduce it (reducing means converting an Ag+ (=silver) ion that lacks an electron, to a silver atom (Ag), which requires adding an electron).

Transferring electrons means the ions of iron and silver must be able to contact each other. That is where moisture comes in...

Moisture helps in facilitating the ions to move in the sensitizer, and thus allow silver to be formed more easily. Naturally, even if the paper feels bone dry, it will still contain a small percentage of water (at least in normal conditions), maybe 10%, so the reaction can still go on, just much slower than when the water content is higher.

[Loris Medici]

Not that I'm absolutely certain about it but:
Moisture in paper helps in mobilizing ions, to react "prematurely" (before physical developer action). That's all. I feel some print-out is good thing, since it should help in preventing solarization - by diminishing light action in the over-exposed parts of the image...

Hope this helps,
Loris.

[Loris Medici]

It seems we have replied at the same time Marco!

[Marco B]

Yes we did, and good we agreed!

[John Lockhart]

Thanks again! I feel much better. I like the results I was getting, but the odd printout made me feel like I was missing something. The spots on my prints reminded me a time when I was in Vietnam and woke up with little red spots all over me. It was bedbugs. Harmless, but totally frightening until I found out what it was.

[Loris Medici]

For me not having print-out is odd. All the alt-processes that I do (except gum dichromate) give me print-out: cyanotype, vandyke, argyrotype, print-out palladium...