If you want a vintage look in your work then dry plate glass negatives may be a good alternative to explore. Depending on your creative vision you can create very high quality negatives using the dry plate process on glass or your can go for an older vintage look that you can only get from the historic processes. You can scan them in or contact print them in the darkroom, or put them in your enlarger and make prints too.
For beginners I would suggest starting with a pre-made emulsion such as Liquid Light or AG-Plus because you have a number of other challenges you need to master first. After you are consistently producing high quality dry plate negatives you may want to pursue making your own emulsion from scratch, but I will tell you it is not easy and it is very time consuming. The Christopher James Book Alternative Photographic Processes is a great place to learn how to make your own emulsion. If you want to start with the pre-made emulsion I would suggest using AG-Plus for your in camera negatives.
Overview of the Process
My goal is to provide readers with a straight forward set of notes to help save you valuable time and money by giving you a good starting place based on experience. You don’t have to do things the way I do because there are no rules and a million ways to get to the same end goal. I share with you my approach and feel free to modify at will. I encourage you to explore alternatives once you are able to produce a consistent negative that meets your creative vision.
There are two very important variables that have the most impact on the quality of the negative. The first is the ability to get the emulsion to stick to the glass plate in a high quality and reliable way and the other is the coating of the emulsion itself makes a huge impact on your final image. While exposure and development are clearly important, they will be a waste of your time if you can’t get your emulsion to stick to your glass. Some of the same techniques are used in Wet Plate so if you have experience with collodion then dry plate will be a short jump for you.
- Cut the glass to fit holders and deburr then wash and dry.
Clean glass on BOTH sides with equal parts mix of calcium carbonate-Everclear-Distilled Water.
Subbing the Glass (Open Light)
Recipe for 12 4×5 plates/6 5×7 plates/4 8×10 plates (leftover mix can be refrigerated for 2 days max)
Heat 50ml of distilled water to 125F in glass beaker.
Pour 1g of chrome alum into the heated water and stir until dissolved.
Sprinkle 3.5g of photo grade gelatin in 1 cup (236ml) of distilled water in glass beaker and let bloom (stand) for 15 min
Heat to approximately 130F until dissolved.
Pour into clean glass beaker then add items from Step C.
Add 5ml (teaspoon) of Chrome Alum from step A into heated gelatin (step b)
Add 15ml (tablespoon) of photoflo to mix (helps flow and coat the plates)
While still warm, pour the mixture (gelatin/chrome alum/photoflo) into flat bottom tray that is just slightly larger than your glass plate and immerse for 15 or so seconds.
Remove plate from tray and use a paper towel to catch any build up in corners before placing in rack to dry. Note: it is hard to see the coating on the glass, but I promise, it is there.
Place the plate in the holder rack overnight before sensitizing the plate. Best to keep plates in a warmer place because you don’t want them too cool at this point. A low humidity and warmer place with circulating air is the best option. Try and avoid any dust as well.
Sensitizing the Plate (Red Safe Light)
I decant my 8 oz bottle of AG-Plus into 35mm canisters. They hold 30ml max. I use about 2o to 22ml (~2ml of Photoflo and 18/20ml of AG-Plus). Approximately ¾ of a canister will pour 3 to 4 plates depending on how thick your pour your plates. I go for thin and even. An 8 oz bottle will fill about 12 canisters for a total of approximately 36 to 48 4×5 plates.
Decant and Prep Emulsion for Use under red safelight conditions
Heat water bath to 130F (up to 140F)
Place AG-Plus container upside down in water bath and heat up (do not shake).
Pour 18 to 20 ml (approx. 2/3rd of canister) of liquefied emulsion into film canisters. I just eyeball the amount and don’t worry about it too much.
Store decanted canisters in cool and dark place. When you are ready to pour and use your plates within a week or so of exposing, move to the next steps.
Step A – (Prepare Emulsion in Safe Light)
I use a red LED headlamp that I got from the hardware store for all of the safe light steps.
Put the subbed plates on a slightly warm heating pad while preparing emulsion. A warm piece of marble tile works good too.
Heat water bath to 130F (up to 140F).
Put dropper full (~2ml) of Photoflo into each canister before coating plates and SLIGHTLY stir with wooden coffee stick.
Stand canisters right side up in water bath and allow them to liquify.
When emulsion is ready (~3 min) remove cap and get ready to pour the plates.
I pour my dry plates like I do collodion (waiter method by holding plate like a waiter tray in left hand and pouring with right hand). I then control the flow of emulsion by tilting and leaning the plate in whatever direction is needed. I pour a big circular puddle of emulsion in the middle of the plate and work it to each corner.
Step B – (Pour Emulsion)
Pick up plate off heating pad and pour emulsion in center of plate and spread into a thin and even layer as described above.
Ensure the coating is as even as possible.
Wipe any excess off the back of the plates with a paper towel.
Inspect for any large air bubbles and blow them to the edge if possible.
Place newly poured plate on cool marble tile until it sets up. You can get marble tile from Home Depot for a few dollars.
Drying & Storage
After plate is ready place flat in the light proof dry storage box for a minimum of 24 hours before use. The longer before use the more contrast and higher the ISO will “likely” be. If possible I aim for 48 hours to expose after pouring.
Ensure drying box has ventilation and I put silica gel packages in the box for faster results. If you are not using silica gels than you can change plates into fresh set of boxes after 12 hrs if you can because the box soaks up the moisture.
Newly prepared plates can be stored in light tight bag/box with interleaving paper between the plates for up to a week or so until you load them into your plate holders for exposure.
Contrast and Speed of Emulsion
The contrast and speed of AG-Plus can be increased.
Mix 15cc’s (1 tablespoon) of Working Dektol (1+2) to 150cc (5 oz) of Ag-Plus.
Effectively 1 part working Dektol to 10 parts of AG-Plus.
We are all on our own when it comes to dialing in the proper exposure because too many variables are involved and it must be based on your own requirements. However there are some general guidelines that you can use to get started. Understand that producing a desirable dry plate glass negative involves the actual exposure with your camera and the development process. I use a white tray for development and develop by inspection. You will know what to look for after you make some prints from your negatives. I make all sorts of prints ranging from gelatin silver to many different types of POP prints (salt, van dykes, albumen, Pt/Pd, etc).
Assume an ISO of 1 as a place to start testing. Expose for the ground because the sky is always going to be blown out unless you are really lucky, or really good! If you think you are going to get detailed puffy clouds most of the time then you can stop reading now and go buy some sheet film. Depending on a number of variables (emulsion, UV light, temperature, etc) your actual ISO could range anywhere from 1/2 to 1 when using AG-Plus. If you move on to making your own emulsion you will have to start from scratch.
For outdoor exposures use the Sunny 16 Rule. ISO is assumed to be 1 so it would be 1 sec at f/16 for sunny day. Keep in mind that if you want to control your aperture for creative purposes then just use normal light principles for all of photography (each f/stop equals 1 stop of light. Bigger apertures, meaning smaller numbers let more light in and you would half your time for each stop. If you want more depth of field and a smaller aperture (bigger numbers) then you would need to double your time for each stop).
For illustration purposes assume you were going to use f/16 at 1 second on a bright sunny day but wanted more depth of field so you were going to use f/22. That is a smaller aperture and so you will need more light for proper exposures. Since it is one stop you would just double your base exposure time of 1 second to 2 seconds for f/22. If you wanted to go to f/32 that would be two stops and you would need to double again or multiply the base times 4 for a total exposure time of 4 seconds. If you are shooting large format then you may need to compensate for bellows draw as you normally wood no matter the medium.
Sunny 16 General Guidelines
f/16 in the bright sun. 1 sec (base exposure of 1 sec assuming an ISO of 1)
f/11 on fairly sunny day (-1 stop from base)
f/8 shade (-2 stops from base)
f/5.6 deep shade/sunset/sunrise (-3 stops from base)
For snow or white sand -1 stop (+1 stop from base)
Development & Processing
Develop – Dektol 1+3 at 65-68F for 1 to 2 minutes by inspection (white tray with slow continuous agitation/rocking motion)
Short Stop Bath –worn out fixer for 20 seconds in tray works just fine. Don’t use acidic stop bath.
Fresh Kodak Hardening Fixer + 1 cap hardener for up to 10 min (all chalky areas turn translucent). Use black tray to make it easier.
Quick Wash 2 min with running tap water.
Hypo Clearing Agent – 4 min (continuous slow rocking motion with tray)
Scrape off any excess off the back of the plate with a razor blade.
Wash with clean tap water for 10 min in print washer or tray with a siphon.
Stand on paper towel for a few seconds and then move to drying rack. You may have to touch paper towel to corner to get the small puddles.
Dry in warm, dry area with a fan blowing.
Go make a print.
I hope this information was helpful to you and if you start making dry plate negatives send me a note and let me know how you are doing.
If you have any questions or comments, I am always glad to help.