in regards to the pipettes, I know you asked Kerik specifically, but I think my process came circuitiously from Kerik's method. I use 2 pipettes one for the Ferric Oxalate and one for the specific metal salt. (IE one pipette for Pd, one for Pt) And I use an eye dropper for the Na2.
I use the 5ml pipettes/pumps since Im measuring out usually 12x20 amounts (2.4ml, a 1ml pipette would likely suffice just fine for everything up to 8x10 prints. It has seemed to me that 5ml pipettes work well for 8x10-16x20+/-.
Basically 10 sq/inches of negative area = 0.1ml of solution. That seems to be a safe and general starting point with slight variations for papers I've found.
This "rule" allows for adequate overcoating (8x10 print on 11x14 paper etc) to get as even a coat as possible.
For example:
8x10 negative (80sq/inchs) = 0.8ml of Ferric Oxalate, 0.8ml of Palladium + your Na2 amount. OR 0.8ml Ferric Oxalate and some combination of pt/pd equalling 0.8ml
4x5 negative (20sq/in) = 0.2ml of FO, 0.2 ml of Pd (etc) + Na2. Ive found this to be a little on the low side so I usually use 0.3ml/0.3ml
12x20 negative (240sq/in) = 2.4ml FO, 2.4ml Pd + Na2
7x17/11x14 negative (119 -154 sq/in) = 1.2-1.5ml FO, 1.2-1.5ml Pd +Na2
Clay Harmon mentioned this to me when I was starting out printing the big 12x20s and it seems to hold true for almost all sizes Ive printed in. Its a perfect starting point that can be adjusted to the unique paper needs etc.
so basically the chicken scratch on the bottom of each of my 12x20 prints goes like this:
FO/Pd/Na2 drops & % - printing time
2.4/2.4/4d 5% - 6 mins
Pipettes -- when you purchase one, be certain that you understand which of the two types you get and measure accordingly....they are calibrated differently, and for small amounts of undiluted NA2 you can introduce some differences. The first type requires you to "blow out" the last drop, while the other type is calibrated such that when the top of the pipette is open to the atmosphere, liquid remains in the tip.
Frankly it does not matter which type you get as long as you know how to deal with that last bit.
Get a good pipette pump. While you can self-aspirate using a length of tubing (don't ever use your mouth on the end of the pipette!), the pump is so much easier. Dick shows a self-built pump in his book using a glass syringe and tubing as an alternative. I've used that at one of his workshops, but the pump is easier to use.
As for dilution of NA2 using small amounts -- see Arentz's latest volume. The table is right there.
Pipettes and pumps. The top 2 are 2ml and the bottom one is 1 ml. These do not blow the last drop out. You stop when you reach the mark at the bottom if you are using a full 2ml or 1ml. Then you draw more solution if needed. The same size pump can be used for the 2ml as is used for the 1ml. http://www.apug.org/forums/attachmen...1&d=1201726150
Also different papers will require different amounts. Some papers require more solution to coat well than others. That is a variable you must determine when you try a new paper. Humidity also plays a roll. As Don said Arentz's charts takes the guess work out of it and provides a very good starting point for your mixtures. Robert
Sponsored Ad. (Subscribers to APUG
have the option to remove this ad.)
A little better pic of the graduations of the 2ml and 1ml pipettes. Because the measurement ends before the tip these are considered Mohr pipettes. I think that is how they are classified. The pipettes that empty out the tip are classified as serological pipettes. I'm sure someone will correct me if I'm wrong.http://www.apug.org/forums/attachmen...1&d=1201728199
It all boils down to developing a consistent work flow. For instance; If I'm going to use Platine to print I'll adjust my humidity to 60% the night before and take the paper out and just let it sit in that environment overnight. The next day it will be humidified to print well with. But all papers are not alike. If I use Swiss Opaline it will not require as much humidity and it will still use 30% less solution to coat the same size sheet. Once you get to know the papers you like to print with all this will just be second nature. The only time I usually need to try different variables is when I'm trying a new paper. Robert
First, as the thread seems to have gone off topic, congratulations to David and Scott for adding a good resource for someone interested in plt/pld printing - good job guys.
The discussion about the Na2 would make a good - but seperate thread (IMO). How each of us works with Na2 (or any other method - such as expousre using Zone, BTZS, etc) is one of personal choice. While many find the need to work precise manner, others are happy to work with a more general approach. It comes down to what makes us happy - let's face it Kerik's prints look just fine so his method works for him, Dick Arentz is well known for his work so his method work for him.
It wasn't my intention to dispute anyone's method. I totally agree what works for one may not suit another. The question was asked how to use pipettes and I was just pointing out that with the proper tools you can eliminate the need to have 4 different bottles of Na2. Dick's approach makes this very simple and as some think, more precise. That is not to say that another approach is inferior. I've used the dropper method and pipettes. They both will work fine. But as I moved up to ULF prints I find that Dick's method using pipettes and using his charts much easier and faster than counting out drops for 8x20 and 12x20 prints and it eliminates the need for so many different solutions of Na2. Especially if you have a densitometer and can determine the density range of your negative. But what works for me may not suit someone else. I was not trying to downplay anyone's method but just offering a different way of achieving the same end. As far as this being off topic, I think it was the author of the article that mentioned going to a pipette system the next time he orders Na2. That is what brought pipettes into the discussion. But I will happily have all my posts removed if you feel it has derailed this thread. Robert
pipettes 
Linear Mode
