Re: Bostick & Sullivan kits
Any subtle differences probably can not be seem on a computer screen. There will be a slight color difference between using platinum or palladium, or in combination.
Generally I do not use Na2, but do when using lower contrast roll film negatives. Otherwise I use a 2:1 ratio of palladium to platinum, and no contrast agents (I get the contrast I want on the negative.)
Using Potassium chlorate in the Ferric oxalate for increasing contrast works well, but it has an upper limit for increasing contrast -- it starts to get grainy. That's where the Na2 method works better. Note that NA2 can only be used with palladium...using it with platinum nullifies its contrast effect.
Re: Bostick & Sullivan kits
I would give you the same answers as Vaughn and add, I suggest students begin with Palladium, no Na2. I haven't used any contrast agent in more than 20 years. Begin with learning to make a proper negative, and most of your woes with Pt, Pd will be over. Since you have been making salt prints you should already be familiar with making long scale (more contrasty) negatives. If not, it is time to learn, think of it as saving a lot of money over the next few years. Proper film choice is the starting point.
Re: Bostick & Sullivan kits
I'll add in the recommendation to start with the Palladium/NA2 kit because palladium is a much more forgiving material than platinum. If you want the cold tone of platinum, there are a number of ways to achieve that with palladium - either through toning or various contrast agents (such as NA2, which is a salt of platinum). Trying to do pure platinum when starting out is a recipe for frustration and disappointment. Pure platinum prints are often very grainy, and contrast control options are more limited (you can use dichromated developer or incorporate dichromates in the printing solution). As others have suggested, best to get your contrast right in the negative beforehand so you don't have to use any contrast agent in printing.
Re: Bostick & Sullivan kits
What's a "proper" negative? My negatives have a good contrast range, but I'm used to the luxury of VC printing and making small tweaks to taste when printing. Are you saying with Pt / Pd you want to get the negative exactly where you want your contrast to be with no tweaking during printing? Would a negative suitable for VC printing around grade 2 1/2 be suitable for Pt/Pd or would you need a significantly different contrast range?
I was confused by the different kits also. Maybe starting with simple Pd as suggested is a good idea.
Re: Bostick & Sullivan kits
A proper negative for palladium wil print nicely at "0" or "1/2". Grade 2 1/2 is far too contrasty a paper grade for Pd or Pt. It is even more so for Salt.
Several years ago I had the opportunity to print a waxedpaper negative from the 1840's which was designed for Salted paper. There is no silver gelatin paper which will print such a negative correctly. Others had attempted to print the negative for a show, and all prints were total failures. They were far too contrasty.
Re: Bostick & Sullivan kits
Quote:
Originally Posted by
Jim Noel
A proper negative for palladium wil print nicely at "0" or "1/2". Grade 2 1/2 is far too contrasty a paper grade for Pd or Pt. It is even more so for Salt.
Very happy to have you and Vaughn available for a little hand-holding (I'm in the process of building my own UV box.:)) A couple of questions:
1.) Do I remember rightly you underexpose a bit? I'd be curious how many stops, say, for FP4+.
2.) When you're in the field, is there a particular minimum "Subject Brightness Range" that you have in mind so that you're left with a reasonable expanded development? (Maybe not an issue out in sun-splashed SoCal, but it gets pretty dark in my East Tennessee hollers.)
Re: Bostick & Sullivan kits
Quote:
Originally Posted by
CreationBear
Very happy to have you and Vaughn available for a little hand-holding (I'm in the process of building my own UV box.:)) A couple of questions:
1.) Do I remember rightly you underexpose a bit? I'd be curious how many stops, say, for FP4+.
2.) When you're in the field, is there a particular minimum "Subject Brightness Range" that you have in mind so that you're left with a reasonable expanded development? (Maybe not an issue out in sun-splashed SoCal, but it gets pretty dark in my East Tennessee hollers.)
The general guideline is expose as normal, but over-develop by 20%. But that also depends on what developer you're using for your film. That's what I do with my FP4+ in Pyrocat HD 1:1:100. I give the same time, 11:00, but I run my chemistry at 75F instead of 68, and I develop in a Jobo with continuous agitation.
Re: Bostick & Sullivan kits
Quote:
Originally Posted by
Scott Davis
but I run my chemistry at 75F
.
Excellent, thanks--as you might expect my temps naturally fall toward the high end most of the year, so that wouldn't be a problem. I might also try to explore some sort of continuous agitation (probably with BTZS tubes) as well.
Re: Bostick & Sullivan kits
I always attempt to expose correctly. Rarely does the light call for slight under-exposure.