Having problems keeping digital negatives flat

[Mainecoonmaniac]

I've been making Ziatype prints for a while now. If I print 8x10 or smaller, my negs lay pretty flat. When I make prints that are 8x13, I get patches that are blurry due to the digital neg having full contact on the paper. The coated paper buckles on area coated with an emulsion. Do I need to use a vacuum frame for making larger prints or is here a method of getting by without one? I use DIY 16x20 printing frame which works OK. Any insight would be great.

 

[E. von Hoegh]

Never have used digital negatives, but I contact print under a piece of 5/8" glass cut from a glass tabletop.

 

[glbeas]

If you live near Atlanta I have an old vacuum frame for you. As far as the buckling you can try a thin mylar sheet betwwen the neg and paper to isolate it from the moisture in the paper.

 

[Mainecoonmaniac]

If you live near Atlanta I have an old vacuum frame for you. As far as the buckling you can try a thin mylar sheet betwwen the neg and paper to isolate it from the moisture in the paper.

Thank you Gary. That's very nice of you. I'm feeling that Southern hospitality. But unfortunately, I'm in California. But I will give the mylar trick a try.
Cheers!
Don

 

[faberryman]

Sandy King recommends a vacuum frame for larger than 8x10, but I have had good luck using a 16x20 contact printing frame with an additional piece of glass at the back for up to 10x15. I'm using Hahnemuhle Platinum Rag paper for PtPd.

 

[Mainecoonmaniac]

Sandy King recommends a vacuum frame for larger than 8x10, but I have had good luck using a 16x20 contact printing frame with an additional piece of glass at the back for up to 10x15. I'm using Hahnemuhle Platinum Rag paper for PtPd.

Mr. King's recommendation is a good one. I'm thinking the buckling is possibly related to ambient humidity. Maybe is the difference in moisture content between the coated part of the print and the uncoated parts.

 

[faberryman]

My HPR lies pretty flat after coating. You are not using too much sensitizer and oversaturating the paper are you? I use a total of 3ml (1.5 + 1.5) of solution for a 10x15.

 

[Mainecoonmaniac]

My HPR lies pretty flat after coating. You are not using too much sensitizer and oversaturating the paper are you? I use a total of 3ml (1.5 + 1.5) of solution for a 10x15.

That is a possibility. But since Ziatypes are expensive to produce, I try not to waste the chemistry by not over saturating the paper. I use a glass coating rod. For my 8"x13" prints, I'll use a total 48 drops of all the chemistry. I could try to pare back on the drops.

 

[faberryman]

That is a possibility. But since Ziatypes are expensive to produce, I try not to waste the chemistry by not over saturating the paper. I use a glass coating rod. For my 8"x13" prints, I'll use a total 48 drops of all the chemistry. I could try to pare back on the drops.

I use the equivalent of 56 drops with a brush for 9.25x13.875, so using too much sensitizer isn't the issue. What paper are you using?

 

[Mainecoonmaniac]

I use the equivalent of 56 drops with a brush for 9.25x13.875, so using too much sensitizer isn't the issue. What paper are you using?

I'm using Revere Platinum paper. What paper do you prefer?

 

[faberryman]

I'm using Revere Platinum paper. What paper do you prefer?

I've tried Revere Platinum and liked it. I settled on Hanhnemuhle Platinum Rag because I like it, and can buy it by the 50"x33' roll and cut it to 12x16 with little waste. Gives me a little extra room over the 11x15 single sheets or 22x30 quartered, and saves a little money too.

 

[Eric Rose]

Must be those darn pixels clumping up and shrinking.

 

[Mainecoonmaniac]

I've tried Revere Platinum and liked it. I settled on Hanhnemuhle Platinum Rag because I like it, and can buy it by the 50"x33' roll and cut it to 12x16 with little waste. Gives me a little extra room over the 11x15 single sheets or 22x30 quartered, and saves a little money too.

Thanks for the information. I'm sure buying it by the roll offers some savings. Is it the 300 GSM version?