Oil Prints From Collodion Dry Plate Negatives

PIGMENT PRINTS
Over the past couple of years, I’ve talked a lot about making Rawlins Oil Prints. And specifically, Oil Prints on glass. You can visit my YouTube channel and watch me make both paper prints and glass prints. And now that I have a couple of good collodion dry plate negatives, I’m getting set up to run some Oil Prints.

My interest is two-fold; first, I want to have some ability to manipulate the image. Not only color but what you want to emphasize or not. This process allows you to do that. Secondly, I have the ability to create “color” images. I don’t mean RGB color images, I mean I can apply different colors of ink to the print. I prefer Senefelder's Crayon Black (1803) and Black lithographic ink.

This is how it works: Apply an 8% solution of gelatin onto a good paper. I use Photo Bloom 250, but you can use regular Knox plain gelatin from the grocery store. I like several papers; Hahnemühle Platinum Rag, Arches Platine, and Revere Platinum. I’ve also used Yupo paper. It’s a “plastic” paper that works well and clears fast, but I’m not a big fan of plastic photographs.

After the gelatin is dry, apply a 10% dichromate/acetone (or alcohol) mixture. This is what sensitizes the gelatin. Allow the sensitizer to dry and the paper is ready for the negative and for the exposure. What happens is when the strong UV light hits the gelatin where the shadow areas are, it hardens the gelatin. The highlights are basically unexposed and the gelatin remains.

After exposure, wash the dichromate from the gelatin. This takes about 20 minutes. The gelatin will clear and it will swell, too. This is called a matrix. The swollen gelatin refers to the highlights in the image and the non-swollen, or hardened gelatin refers to the shadow areas.

Time to “ink-up” the print. With the matrix swollen, use any lithographic ink and slowly apply it to the print. It will ink the shadow areas and the swollen gelatin in the highlights will resist the ink. This is where it gets its name, “Oil Printing” like oil and water - resistance. The highlights stay “paperwhite” and the shadows are full of ink.

There are a lot more subtleties to inking up and it takes practice and time. The ability to make really fine, exquisite prints is very achievable. They are very painterly and would fall into the category of Pictorialism. This is an aesthetic that I’m very interested in applying to this work. Stay tuned!

Checking Density (Dmax/Dmin) On Wet Collodion Negatives

The Wet Collodion Negative - varnished and ready to run some test prints on Platinum Palladium and Rawlins Oil!

The Equation
Dmax: The area with the most density with detail.
Dmin: The area with the least amount of density with detail.
Subtract the Dmin from the Dmax and that is your NEGATIVE DENSITY.

The Print
If you want to maximize the quality of a print, you need to know what the Dmax/Dmin, or density of your negative is - maximum density (with detail), where the most silver is deposited. This is the brightest or highlight area(s). The thinnest part with detail is your Dmin area - approaching the void area or shadow(s). And everything else in between is the middle tones or middle values.

Why is it important? Not every negative will print well on every POP (Printing Out Process) or DOP (Developing Out Process). Some require density in the 2.0+ range - like Salt Paper. And some require less density. If you fail to match the negative with the process, it will never be as good of a print as possible if it were matched up.

In my opinion, you should choose a printing process and make negatives exclusively for that process. I’m not saying you can’t print a “Salt Negative” on Colodio-Chloride paper, you can. What I’m saying is that it will never be as good as a Salt print and vice versus.

My plans for this project are two types of prints. Both are “non-silver” and one is a pigment process. They are Platinum Palladium (mostly Palladium) and Rawlins Oil prints. I’ve made many Rawlins Oil prints and know that good negatives are almost identical to the Platinum Palladium process. The density of 1.50 - 1.80 is perfect. I can get great prints all the way to 2.0.

What happens if you don’t get the proper exposure or development on the negative? What can you do? Rarely are you too dense; I’m not talking about over-exposure, but getting in the density of 2.0+ with a foundation negative, or a negative straight out the camera. Most of the time they will be a bit under the desired density for technical reasons (fogging the shadow areas). If you need more density, you can do that chemically with pyrogallic acid and citric acid plus a bit of silver nitrate. This is called redevelopment and you can take it as far as you desire regarding density. Problem solved.

The Negative
Today, I varnished and prepared my test plate for my first run of the Platinum Palladium process and Rawlins Oil process. I checked the Dmax and found that where the light was hitting the back of the stump, my highlights, with details, ranging from 1.75 to 1.80. And the areas with the thinnest silver (some weeds in the foreground) that still had detail registered as 0.20 - that means if I subtract the Dmin from the Dmax I have a density of 1.59 - or thereabout. This should be a perfect negative for the processes. I’ll soon find out!