Oxalic acid bath for Clearprint Vellum?

Jeremy · Oct 7, 2004

The subject line pretty much says it all.

I oxalic acid treat my stonehenge rising paper and the prints I have on platine were treated to a bath in the acid also. I have one print on clearprint vellum that has a deep black (double-coated) and wasn't treated in oxalic acid.

Is a dip in oxalic suggested for clearprint vellum?

clay · Oct 7, 2004

Not needed at all. Just do two lighter coats ~75% of typical volume and forced air dry in between.

Jeremy · Oct 7, 2004

Thanks, Clay, I am going to try and set-up my PDN curve tonight. I remember that I should tape the vellum down and coat the whole thing at once--that seemed to help a lot with the "potato chip factor."

Mateo · Oct 7, 2004

Jeremy,

Do you need the acid bath for Platine? I've used it without the pre-bath no problem. Only problem I've had is finding the black spots and cutting the paper to make it work.

sanking · Oct 7, 2004

clay said:
Not needed at all. Just do two lighter coats ~75% of typical volume and forced air dry in between.

Same experience here. Clearprint Vellum gives good Dmax without any oxalic acid soak.

One problem I have had with Rising Stonhenge is that the oxalic acid soak appears to remove the surface sizing, which opens up the texture and results in a very grainy kind of image in the uppper highlights. I have also seen this with a few other papers. The oxalic soak is good in that it increases Dmax, but the resultant grainy look is quite unpleasant.

What I would ask, and Clay most likely knows as much about this as anyone I could ask, is which papers work well with the oxalic acid soak and which don't.

Sandy

clay · Oct 7, 2004

I think that the ones which behave the best are the heavily body-sized papers - the 'floaters'. I now typically only treat the Fabriano Extra White, Rives BFK, and Whatman's watercolor paper with the oxalic acid. The others such as platine, COT320 and Stonehenge do better with just straight double coating. Reports from some people are that diluting the first coat with 1/3 to 1/2 the volume with distilled water works fine as well. I just bite the bullet and double coat - which is much easier with cheaper palladium!

donbga · Oct 7, 2004

Jeremy Moore said:
and the prints I have on platine were treated to a bath in the acid also.

Jeremy,

I've never needed to treat Platine with oxalic acid.

I've also wondered if adding oxalic acid to the FO might have the same effect as soaking.

Don

Jeremy · Oct 7, 2004

The only prints I have on platine I made at a workshop taught by Clay and the sheets of platine I used were marked as being pre-treated in oxalic acid.

Sandy, I will have to try some of my stonehenge w/o the oxalic treatment. I noticed the graininess in the highlights, too, but thought it was just a characteristic of the paper.

Any suggestions on whether or not to pre-treat Lennox paper? I think I am going to pick some up to try next time I am out in Dallas. If it works out well my paper cost is going to drop big time! $1.89/full sheet Lennox; $11.99/50 sheet pad of 8.5x11" Clearprint Vellum.

Oxalic acid bath for Clearprint Vellum?

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