"alkaline reserve" might not be composed of a carbonate that generates carbon dioxide when treated with acid.
As shown by others in the last couple posts, the company says it does contain calcium carbonate.Your 'no fizz' result strongly suggests that Arches Aquarelle does not contain a carbonate buffer. Have you tried an exposure on the paper as you received it?
Also, why are you coating the back side? Some papers have two very different surfaces. I suggest that you try coating the front side as well just to see what happens.
Spit-balling theory: sizing on both sides is protecting the sensitizer from the bulk of calcium carbonate? Company also claims the paper has “sizing to the core” which might also come into play?
...I guess if your pints come out OK (Dmin's at paper white or close) then all is good.
:Niranjan.
Looking at what is supposed to be the 'max white' border along the tablets edges, it appears to be fogged a bit...is this an indication that pre-acidification is required? Will try that today or tomorrow, just to be sure.
Thanks...will definitely chip away at all your suggestionsThat might help. Also noticed you are not using any citric acid. Perhaps you didn't need it on HPR, but might be useful here. That would be my first line of defense - I'd rather not do acid treatment if I don't have to. Also, does it look like the shadows from 92-100% are kind of clumped up. Exposure time could be shorter? That might cut the fog somewhat too.
:Niranjan.
Hi again....Also noticed you are not using any citric acid. Perhaps you didn't need it on HPR, but might be useful here...
:Niranjan.
Hi again.
I've been using Ellie Young's book, The Salt Print Manual. She mentions citric acid in arrowroot sizing and in Pt/Pl toners.
Are you suggesting citric acid for neutralizing calcium carbonate (like adding it to the salt solution?) or somewhere else in the process?
Ahhhh, thanks for the clarification...really appreciate the time it takes to answer.OK...I don't even remember where I saw the use of citric acid first. It's not in Young's book - you are right. Also not in O'Reilley. Might have been James. Most people add CA to the silver nitrate (to the ratio of 1:2 resp) just before coating. Say you are using 12% silver, then actually make 24% silver solution and a 12% CA solution and then mix equal drops of each. I found it a little cumbersome to make this mixture (some make a 40-50% solution and add a drop or two like how T-20 is done,) so I have started using the CA in the salt solution recently - it is easier as you can keep the solution unlike in silver where it will precipitate silver citrate over time in the bottle. Salt solution is then 2% NaCl + 6% CA.
Use of CA in this context is not so much as countering the buffer - although it might do that as well. But even in un-buffered papers, it can work to improve the Dmin - both by suppressing the "dark" reaction (as a preservative) and cleaning up the 0 step. I do see these benefits on COT 320, both when added to the silver and added to the salt. But like anyhting in alt world, YMMV.
:Niranjan.
Here's the one from earlier today; the one that got the decalcification citric acid bath and then dried before coating. Photo is a fairly good representation, but nowhere near precise! (The white is overly warm in an attempt to get the gray tones to look something like the print).
Looks like you were right, Niranjan...the dark tones got some separation with reduced exposure.
Much less warmth than the last one, has smoother grain structure overall, has less 'fogging' in the white border of the step tablet, and the lightest square is closer to paper white.
Will do a max black test next, because it might need another minute or so of exposure. Will also probably make another negative and go from either Epson Advanced Black & White 'Normal' to 'Dark' density, or stay at 'Normal' and add 75 yellow.
Being pretty loosey-goosey at this early stage...laying a base for what I hope may become an intuitive level of understanding. Also, haven't settled on a paper yet and intend to tone in either platinum, palladium, or a combination of both once things get serious.
The colour shift is amazing. In the initial water wash it appears to be made of cranberry with a dash of beets, changes a bit in the toner, a bit more in the fix, then radically swings to the cooler end of things as it dries.Wow...that is a great improvement. I like the tone better here, almost like eggplant and the highlights look more cheerful. Most of all, the grain and surface imperfections in the earlier print are nearly gone - I wonder if one of the side effect of doing the acid treatment is homogenizing the surface chemistry/physics somehow. Perhaps just the act of washing is responsible for this change - irrespective of the pH. Might be worthwhile to do this even if you don't need the buffer neutralization. I sense a set of experiments coming...
Thanks for sharing!
:Niranjan.
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