Welcome to the New Dry Plate Era!
HOW DRY PLATES CAME TO BE?
There are two basic types of glass plate negatives: collodion wet plate and gelatin dry plate. Wet plates, invented by Frederick Scoff Archer in 1851, were using glass instead of paper as a support, producing a sharper, more stable and detailed negative that was reproducible. The photographer, however, was constantly fighting the clock as the plates had to remain wet throughout the process and therefore had to be processed very quickly after exposure. Because of that the process of making photographs was complicated, inconvenient, and not very portable.
Research and advancement continued and in 1871 Dr. Richard L. Maddox invented a Silver Gelatin coated Dry Plate negative as a way more practical substitute to wet plates. They were usable when dry and thus more easily transported, and required less exposure to light than the wet plates. Emulsion is typically coated on thinner glass plates and emulsion is more evenly distributed resulting in negatives of much higher quality. Dry plate glass negatives were in common use between the 1880s and the late 1920s when glass base was substituted with modern cellulose films and colour blind emulsion superseded by much faster ortho & panchromatic emulsions. Companies soon abandoned commercial production of glass Dry Plates and besides a few enthusiasts experimenting at home they were pretty much lost in time for good.
ZEBRA STANDARD ISO 2 DRY PLATES
Zebra Standard ISO 2 Dry Plates are a modern take on high quality Dry Plates of the 1890s. Just like in the old days they are hand coated (poured) with ultra fine grain silver gelatine emulsion that is sensitive only to UV and blue light. Contrast of the plates is moderate to high making them ideal for further use with alternative printing processes. However despite the high contrast there is less separation in the shadows meaning they can also be scanned and digitized with great results. Plates are rated at ASA 2 under winter lighting at middle latitudes, but as with other primitive processes, the effective speed of the plate will vary for a few stops depending on actual UV levels. Zebra Dry Plates are completely hand made and therefore kept to the highest standard of excellence and embody all the latest improvements.
STORAGE & SHELF LIFE
I advise you to store the plates the same way as it’s recommended with the film. Meaning you should keep them in a dry and cool place with temperatures at around 13°C or lover and humidity below 60%. To put it simply, storage in the fridge is perfect. I would not recommend you to store them in the freezer though as when you take them out the condensation from the temperature may cause the emulsion to swell and bond to wrapping paper!
How long do they last for?
It’s like with film the fresher the better but with my experience if stored properly they will last for at least 2 years without any fogging or speed loss!
HANDLING & LOADING DRY PLATES IN THE THE PLATE HOLDER
Start by opening the box of Zebra Dry Plates under Red Safelights. Inside of the box plates are protected from the light with a sealed black dark bag. Remove the seal and open the bag. Inside you will find plates individually wrapped into acid free archival paper. Gently pull the individual plate out of the stack and start unwrapping it. Just like with any other photographic material you should not touch the emulsion side! You should handle the plate by the edges
Which is the emulsion side?
Plates are wrapped in the protective paper emulsion side down. So when you unwrap and flip the plate around this is the emulsion side. Otherwise upon carefully examining them you will notice that one side is coated with a thin white film and the other being plain reflective glass.
How to load them into the holder?
Before loading the plates pull out the double dark slide from the holder and slide or place the plate inside. If you are using Zebra Dual Plate Holder slide the plate into the slots emulsion side facing up. If you are using a back loading holder which is usually used for wet plates make sure that you place the plate into the holder emulsion side facing down. After you have the plates in slides must be carefully shut closed.
Once your plates are loaded a very great care must be taken that you fold the black bag with remaining plates in the starting position, reinstall the seal and place the wrapped plates back into the box as the sudden opening of the dark room door, or the slightest admission of daylight, would effectively spoil the whole box of plates, making them fogged and therefore useless.
EXPOSURE OF THE PLATE
MONTHLY EXPOSURE GUIDES:
Monthly Exposure Guides where adjusted according to the Slovenian monthly UV Index levels listed in the chart bellow. Depending where you live monthly UV levels can be completely different to ours so adjust exposure guides accordingly.
SAMPLE OF CORRECTLY EXPOSED ZEBRA DRY PLATE
What does the correctly exposed Zebra Dry Plate look like? Everybody would answer this question differently depending of the look they prefer but in general we could say that the correctly exposed plate is full of detail in all but the brightest and darkest areas of the negative. Bellow is an example of such a Dry Plate exposed by Heiko Krause using a 1915 ICA Palmos Universal camera and Doppel-Protar 1:6,3 130 mm lens. Exposure time was 4min at f/16.
KEEPING A RECORD
When you are starting out it’s advisable to keep notes with a record of all exposures and memoranda made of conditions of light, time of the day, etc. This is highly necessary especially if you have shot more than a few plates as you can with your first developed plate determine whether or not you have over or under exposed and adjust the development of remaining plates accordingly. Whenever you are trying something new the temptation to just go out and photograph whatever interesting comes along is very high. But remember you don’t have an endless amount of exposures left so calm down and take your time to run some exposure & development tests that will help you with following exposures. When making exposures keep in mind that blue sensitive emulsions “see” much differently than we do and that requires a bit different approach than you are used to with modern film. There are a few things you need to take into consideration like the amount of UV light present in the scene, color of the subject, color of light…
ADDITIONAL EXPOSURE COMPENSATIONS
TIPS FOR SHOOTING INDOORS
When making exposure indoors under artificial lights (Tungsten, Fluorescent, LED) where there is very little to none UV light I recommend you to use a light meter, meter at box speed (ISO 2) and add 3 stops of exposure. Unless you are working under very strong lights there is a very high chance for your exposures to quickly be several minutes long and reciprocity failure will have to be taken into account as well.
Since Zebra Standard ISO2 Dry Plates are coated with ultra fine grain emulsion reciprocity will have no visible effect up to 1min of exposure. After 1min I recommend extending your exposure time for 50% or to double your exposure time with exposures over 2min.
BELLOW EXTENSION FACTOR
Whenever you want to focus on something close to the camera your bellows will extend wide. Because of the long distance between the lens and film plane some light will get lost and you will have to account for the so-called bellows extension factor that gets added to the exposure. This is where you have to pull out a ruler from your camera bag and start measuring.
The equation is very simple and it goes like this:
Bellow extension squared divided by the lens focal length squared. Measure your bellow extension from the lens board to the focal plane. For instance if your bellow extension is 260mm or 67.600mm squared divided by the focal length which is 235mm or 55.225mm squared you get a factor of 1,224 which you can round to 1,2 and this is your bellow extension factor. You need to multiply your exposure with the factor of 1,2.
EFFECT OF ALTITUDE ON THE SPEED
If you plan to carry those heavy glass plates higher up in the mountains you have my admiration but note that with higher altitude also UV levels increase. It depends where in the world you are but the rule of thumb is that with every 1000m of altitude UV levels increase by 10%. If you are shooting in the mountains or at higher altitudes the exposure of Zebra Dry Plates that are mostly sensitive to blue and UV light should be adjusted accordingly. You should reduce your exposure time by 10% with each 1000m above 500m of elevation.
In Alps where UV levels are even higher you can reduce your exposure by 15% with every 1000m above 500m of elevation.
DEVELOPMENT OF THE NEGATIVE
The next process is the development. Many amateurs are under the impression that this is a most tedious and difficult operation, but by carefully following the rules enumerated below success is certain. There are many different developers to choose from, but I will walk you through the basic development procedure using Kodak HC-110 dil B at 20C which is simple to use and has proven time and time again as the perfect match with Zebra Dry Plates. Before you start here are a few important tips you should follow for successful development:
– 1 –
After you have done the exposure and have the exposed plate loaded in the holder ready to be developed, don’t unload it just yet but put the holder together with the plates in the fridge for a few minutes. Why? Well my recent findings have shown that cooling the plate down below the temperature of processing chemicals drastically lowers the chance of plate defects. I know it might sound strange and you won’t find this in any book but my theory is this: if the Dry Plate is warmer than the processing solution glass will start to contract when it gets in contact with the developer. On the other hand gelatine will expand and have hard time to contract together with the glass resulting in a lot of tension that can cause emulsion defects. If you chill the plate below the temperature of processing chemicals glass will expand and so will the emulsion resulting in a perfectly developed plate! This technique is specially recommended during the summer or if you shoot in tropical environments where temperature fluctuations are big.
– 2 –
Plates are not sensitive to the red spectrum of light meaning you can always develop by inspection under red safelight and adjust dev.time if necessary. Learning to develop by inspection comes with time so be patient.
– 3 –
I recommend you to keep your dev. temperature somewhere in the range between 17-21C
– 4 –
To avoid unnecessary stress in the emulsion layer make sure to keep the temperature the same throughout the whole developing process. Temperature fluctuations can cause the emulsion to overswell and it can potentially start lifting, frilling…
– 5 –
While processing, agitate gently. Dry Plate emulsion is primitive and much more fragile compared to sophisticated emulsions used for modern films. I do not recommend you using tongs as there is a very high chance of scratching and damaging the emulsion. Rather put some gloves on and handle the plates by hand.
Since Zebra Dry Plates are not sobbed prior to emulsion coating it is strongly advisable that you follow these tips in order to obtain negatives of maximum possible quality!
TIME OF DEVELOPMENT
If properly exposed, the picture should appear in about 20 to 30 seconds, but the development should be continued for another 4 ½ minutes. To prevent unequal action and any decomposed particles from settling on the plate and causing spots I recommend you to agitate for a few seconds every half a minute. The negative is properly and sufficiently developed when those parts of the picture which were white in the original are almost perfectly opaque in the negative,—the darkest shadows remaining whitish and unaltered under the influence of the developing solution, and the gradations of tone fully preserved. If you are afraid your negative is getting too dark remember you are working under low light conditions and a perfectly developed negative should look a bit darker under safelights.
The development of a plate which has been properly exposed is a much more simple matter than would appear by the description, indeed, it is almost difficult to spoil a picture which has been nicely timed ; on the other hand, as a beginner you will definitely have to face under or over-exposed negatives at some point. In order to still save those negatives during development I am sharing these two facts:
Negatives which have been very under-exposed are useless ; the contrast of light and shade is simply too violent. In the vain attempt to bring detail into the shadows you might extend your development time but the longer the development the greater the failure.
A negative which has been greatly over-exposed bursts into sight at once as soon as it gets in contact with the developing solution, and the image gets fogged all over immediately with very little contrast. But do not give the plate time to go so far as this! As soon as you see that the image is appearing way too quickly wash off the developer without delay and rinse with clean water. If you slightly overexposed you will see the image appearing a few seconds sooner than usual, keep on developing by inspection and cut your development time accordingly.
So whenever you are out in the field deciding what exposure to go for, remember that it’s always better to slightly overexpose and underdevelope than to underexpose.
Developers & Developing times that are proven to work with Zebra Standard ISO 2 Dry Plates:
DIL B (1+31)
HC-110 *less contrast
ILFORD DDX (low contrast developer)
1 min 30s
Bellini EURO HC
If you are successfully using any other developer or dilution please let me know so I can add it to the chart 🙂
After development, move the plate to a water rinse bath for a minute. You can use the same rinse bath as you do for the film which is in my case water.
Before you start fixing the plate you will notice that the back of the plate is quite white and very little of the negative visible when held up to the safe light. The goal of fixing is to clear away all the whiteness (unexposed silver bromide) from the emulsion so that only the negative remains, sharp, clear, and distinct. There are many fixers out there you can use from simple HYPO to more advanced Rapid Fixers whis is what I recommend and work with. I always fix for at least 5min agitating gently and if using Rapid Fix plate should be cleared by then. You can also fix by inspection and observe when all the white areas are gone, after the plate is clear you should continue fixing for another 2min or so. Fixed plate is now ready for final wash.
To insure long life of your image it’s important that you thoroughly wash out all the fixer. I recommend at least 10-15min of washing in running water below 20C. If you are using trays just change the water a couple of times. Insufficiently washed plates can form brown stains and degrade much faster. Addition of PhotoFlo to decrease water surface tension and minimize water marks and drying streaks on negative is recommended but not mandatory!
After final wash the emulsion will still be swollen and therefore very delicate so in order to make it bulletproof, printable or scannable you have to dry it out. Zebra Drying rack was made just for this purpose since the plate will be tilted ensuring optimal water drainage and fast drying time without water marks. Dry the plate in a well ventilated room between 4-12h depending on the temperature and humidity level.
I do not recommend the use of a hair dryer which can indeed speed things up but remember the emulsion is still swollen and will catch all of the dust and dirt you will introduce when blowing. That dust and dirt will then dry in the emulsion and you will never be able to take it out again only with photoshop 😀
COMMON PROBLEMS AND THEIR SOLUTIONS
Lack of contrast and very dense negative
Lack of contrast is often the consequence of over exposure.
SOLUTION: it’s obviously shorter exposure but if you are already developing the negative and the whole picture flashes up at once, cut development accordingly.
Thin negative is mostly a consequence of two causes:
-Insufficient development (to short)
SOLUTION: Develop or expose longer
Emulsion lifts/detaches of the plate
Technically we would call that “ Frilling,” and it’s generally the cause of four things:
– Plate being too warm once it gets into developer
-Your developer is to warm or the temperatures are not the same throughout processing solutions
-You are agitating to aggressively
-You are using a developer that is simply too aggressive and overswells the emulsion (Rodinal).
SOLUTION: After exposure and before development put the exposed plate with the holder in the fridge for a few minutes to cool the glass plate below the temperature of processing chemicals. Keep all of the processing solutions at the same temperature between 18-21C, agitate gently and work with recommended/tested developers listed above.
Yellow/foggy spots on the negative
Yellow spots on the dried negative are often caused by left behind fixer deposits after inadequate final wash.
SOLUTION: Make sure to properly wash the plate after fixing it in fresh water for at least 10min, changing the water a couple of times if you are using dev. trays.
Tiny white spots/bubbles on the negative
They can mostly be traced back to the dust present on the plate during exposure. Even though we do our best to keep air bubbles to a minimum while coating it is still possible for some micro bubbles to be present on the plate.
SOLUTION: Brush the plate with a flat soft-hair brush before insertion in the dark slide to remove any dust. Bubbles from coating can only be removed with retouching the negative either manually or using adequate software.
HOW TO STORE THE NEGATIVES?
To protect the dry plate negative from mechanical damage encase it either in a stable plastic sleeve or simply wrap it back in the protective acid free archival paper left over from when you unwrapped fresh Zebra plate. Store them vertically in a tightly packed manuscript box or in a box equipped with grooves. Negatives will not suffer from exposure to light during printing, or through the contact or enlarging process. Nevertheless, negatives should be stored in the dark to protect them from prolonged exposure to light.
AMONG MANY OTHER DRY PLATE RELATED VIDOES ON MY CHANNEL I ALSO MADE A VIDEO TUTORIAL ON HOW TO USE ZEBRA DRY PLATES
*Some content in the video may be outdated so for the latest findings and instructions check out the written manual above