Rising Stonehenge White Uncoated Art Paper fro P/P

PiezoDN Digital Negatives
1

So, I’m tempted to pick up pack of Rising Stonehenge White Uncoated Art Paper for use mainly in PP printing.
Unfortunately I keep finding mixed info about the paper needing to pretreated before using. So, who among us has used it and did you need to pretreat it? And if you did, what method/chemicals were needed (I keep finding mixed info on this too)?

Thanks,

2

Jallen-

It used to be good, but they changed their formula apparently and now it’s buffered and needs to be acidified. I didn’t want to go through the hassle so I returned a batch of the Stonehenge to B&S a few years ago. They told me I could use an oxalic acid bath, and I’m sure if you search the web you’d find a formula.

However, an authoritative source is Christina Anderson’s book “Cyanotype,” and she recommends sulfamic acid (available at any hardware store as heavy duty cleaner crystals, apparently) . Her formula is as follows for a 10% solution, but she says others use anywhere from 1%-5%:

  1. 100g sulfamic acid to 1000ml water
  2. Add crystals to 750ml to start (crystals to water, not the other way around) and stir
  3. Add remaining water to make 1000ml.
  4. Keep stirring until dissolved, which will take a while
  5. Pre-soak paper in plain water for 20-30 minutes
  6. Transfer the paper to the acid bath for 15-20 minutes, interleaving sheets every few minutes
  7. Once fizzing stops, transfer paper to a water bath and wash for 20-30 minutes or longer until it is cleared completely of the acid.

The acid is caustic so wear gloves and eye pro when you do this.

-Mike