The Rawlins oil print process – a safer version

The Rawlins oil print process, developed in 1904, creates stunning archival quality prints with deep blacks and rich tones using minimal chemistry, Richard Hildred shares a safer version of the process – discover this unique technique making timeless prints.

Writer and photography / Richard B. Hildred ABIPP

WARNING: This is for experienced and advanced users. Read the MSDS (Material Safety Data Sheet) before attempting to use chemicals and use the correct safety equipment.

The Oleotype or Rawlins oil print process, developed by G.E.H. Rawlins in 1904, uses minimal chemistry to create high-quality, archival images on gelatine-coated paper. Despite being the precursor to Bromoil printing, this technique provides rich tonal contrasts, deep blacks, and clean whites. Typically, good quality watercolour paper is coated with a gelatine solution and sensitised using Ferric Ammonium Citrate (FAC) as a safer alternative to banned Dichromates. The process requires controlled UV exposure, precise inking, and careful drying for optimal results, making it an effective method for producing durable, detailed, and archival-quality prints.

Introduction to the Oleotype or Rawlins oil print process

Oleotype or Oil Printing is an early gelatine-based photographic technique that was first described by Louis Poitevin in 1855 but was not seriously practised until 1904 when G.E.H. Rawlins demonstrated its practicalities more comprehensively.

It is generally regarded as the precursor to the classical Bromoil Process, introduced a few years later, which used conventional photographic paper. Yet in its simplicity, Oil Printing often produces amazingly ”photographic” results of the finest quality and archival permanence.

The Oil Printing technique uses unsophisticated chemistry, but can still produce images with incredible blacks, many subtle tones in-between, and clean paper whites.

Importantly, the images produced offer a high degree of permanence with an archival lifespan well in excess of the modern photographic image! Freshly inked images can also be transferred using an etching press similar to the process used in PhotoGravure and Bromoil Transfer.

Rawlins basic oil printing technique

The materials used in Oil Printing are minimal yet very effective!
Firstly, good quality watercolour paper, ideally Hot Press circa 300 gsm, is coated with a solution of gelatine. I find a 10% working solution is favourable since it gives a nice thick coating for your final image.

Good quality food gelatine 250 bloom will be fine, although “photographic quality” will cost you more with very little difference in image quality!

I add a small quantity of Isopropyl Alcohol to my working solution as this aids drying of the gelatine, and more importantly, reduces the bubbles to almost nil.
The newly coated paper must be left to dry in a cool place for at least a couple of days for the best results.
About 60ml of gelatine is used for a single A4+ size sheet.

Once dry, the paper is ready to be sensitised – historically this has always been with one of the Dichromates, either Ammonium or Potassium.
My preference was originally for Potassium Dichromate; however, in recent years, these chemicals have been banned for sale in the European Union and are now essentially illegal for us to use in public places both here in the UK and in the EU. 

Inking can be undertaken in many different ways, either by the classical Bromoil brush, sponges or roller/brayer.

The New Ferric Ammonium Citrate Technique

Since the Dichromate restriction has proved disastrous for a number of our historical imaging processes, new user-friendly chemical methods were needed to enable these classical processes to continue.

With the help and support of my European and American friends, I looked at some of the alternative chemistries such as Diazo, DAS and finally, FAC (Ferric Ammonium Citrate – Material Safety Data Sheet), and to my delight a combination of FAC as the sensitiser, and Hydrogen Peroxide (Material Safety Data Sheet) as the developer, gave me almost identical results to that when I was using Dichromate!

My current practice is to sensitize with a working solution of either +-5% FAC, and I find circa 10ml of sensitizer is more than adequate for an A4+ sized gelatined print. For a second sheet of paper coating, I suggest you use circa 9ml of sensitizer if the brush is still a little “wet” with existing chemistry.
Note: 5% FAC solution gives slightly lower contrast than its Dichromate equivalent.
The initial coating can be done in dimmish room light, but once the sensitizer is applied, I prefer to dry my papers in complete darkness for about 3 to 4 hours. Image exposure and the remaining processing can be done again in dim room light – but not UV or fluorescent light!

Sensitized paper should ideally be used the same day, or ideally within 24 hours, as inconsistent results will be obtained if left longer.

The Difference Between Oil and Bromoil

The main difference between Oil and Bromoil, is that Oil Printing is a contact print process requiring large negatives and UV light for exposure.  Negatives can be original photographic, or ink jet, and printed to any size.  Ideally, an Ultraviolet wavelength of 365 nm or 385 nm will be fine for exposures, although if funds do not permit, you can use the Sun, or a simple domestic facial sun lamp! Generally, exposures for both Dichromate sensitized, and FAC Oil Prints are similar, in the region of 2-5 minutes.

The Difference Between FAC and Dichromate Sensitising

The UV contact printing exposure hardens the gelatine in the appropriate picture areas, and in the case of dichromate sensitizing, the image is finally prepared for inking by washing in cold water for up to an hour, or possibly longer – this is to reduce the yellow staining Dichromate leaves on the paper. However, if you are working with the new FAC process, there is an additional step immediately after UV exposure where the print is immersed in a dilute Hydrogen Peroxide bath for a maximum of 2 minutes. This can be considered as the development, or polymerization stage of the process!

I use 100ml of 3% Hydrogen Peroxide mixed in with 900ml of room temperature water.
Also, quite usefully, since FAC does not stain the paper anywhere near as badly as Dichromate, the cold-water wash can be reduced to around 10-30 minutes – a great bonus!

I believe there are other chemical options such as Potassium Alum or Sodium Sulphite that will reduce the effect of staining by Dichromate or FAC chemistry and this can reduce the overall length of water rinsing, but my process so far has proved acceptable in its clean white reproduction, and as yet I have felt these additional baths were not needed.

The Process

Broadly speaking, I have arranged this section into eight main processes. Whilst others may choose differing percentage strengths of sensitizer and gelatine these are my preferred formulae and working practices for my everyday standardized work.

1Making the 10% Gelatine Solution
Use good quality Powdered Beef Gelatine with 250 Bloom – Grade A Tongmaster.

• Weigh 50 gm into a dry 500ml glass container.
• Mix up 25ml of Isopropyl Alcohol and 25ml of water into a separate container.
• Pour 350ml of distilled water into a separate glass container – room temperature water.
• Slowly pour the gelatine powder gradually into this container mixing carefully with glass rod ensuring you do not get clumping of powder or too many air bubbles and mix thoroughly.
• Leave gelatine to rest for a couple of minutes to slightly thicken – then heat gently for x2 30 second microwave sessions to make gelatine more liquid.
• Pour in about 45ml of the Isopropyl Alcohol/water mix, and then the remaining water to make up to a total working solution of 500ml.

DO NOT OVERHEAT THE GELATINE TO OVER 120 DEGREES FARENHEIT OR 50 DEGREES CENTIGRADE AS THIS WILL LESSEN ITS HARDENING EFFECT.

Important note: You will probably still have some bubbles in the premixed gelatine – the addition of the isopropyl alcohol, slowly mixed with water, eliminates most of the bubbles. You can optionally microwave gently a little if you wish to help the mixture dissolve fully before you pour it into its final container for resting overnight, but do not overheat.

Tip! It is a good idea to scald the container before gelatine is poured into it as this will prevent any growth of mould or bacteria forming prematurely.

Tip! If you can keep a few drops of isopropyl alcohol left over to the very end of the gel-making process you can add this to the final solution in the storage jar to eliminate any remaining small bubbles!

Leave the final mixture to settle and solidify for at least 48 hours before coating on paper.
On paper coating day, pre-heat gelatine for 1 min 30 secs in the microwave and stir gently to ensure thorough mixing but be careful not to stir too vigorously as this will encourage air bubbles.

The working gelatine solution will keep in a closed, airtight brown bottle for up to three months before use, but preferably use within one month to ensure no fungus or mould growth.

2Coating the paper with 10% Gelatine
Coating Day

• Microwave gently to reach the ideal working temperature – about 30 seconds.
• Aim for a final coating temperature of circa 100 degrees Fahrenheit – this slightly lower temperature encourages the gelatine to solidify fairly quickly, ensuring it retains a nice even coat on the paper without spilling over the edges. I usually coat a typical quantity of x4 sheets of paper in any one coating session, as this takes in total time about one hour. Since I generally make up batches of 500ml of gelatine at any one time, this ensures my 500ml gelatine jar is always pretty fresh by way of x2 sets of x4 papers use x1 jar of fresh gelatine = 8 sheets in total.

Preferably use fresh gelatine that was made at least 24 hours or 48 hours previously which has been allowed to settle and stabilise hence reducing the risk of air bubbles.

• Soak good quality watercolour paper, about 300 gsm weight, in distilled or filtered water for a minimum of 5 minutes, 10 minutes maximum at room temperature.

Use either, Arches Platine, HPR – Hahnemühle Platinum Rag, (my latest batch of AP soaks too much water) or preferably, Bockingford 300gm Hot Press or Cold Press – works best for me.

• Preheat the prepared gelatine in the microwave for about 1 min to bring its temperature to circa 100 degrees Fahrenheit or 120 degrees max – stir carefully to ensure thorough mixing but avoid creating any bubbles if at all possible.
• Place pre-soaked paper on a flat metal sheet at about 30 30-degree angle on the side of a 20×16 developing tray. Squeegee excess water off the metal sheet and paper – water lands in the tray.
• Scald the surface of the paper briefly (circa 10-20 seconds) with boiling water from the kettle (you will hear any air bubbles escaping on the paper surface!). This important step helps eliminate almost all air bubbles in the final coating as it appears to evict all air in the body of the paper before the gelatine is applied – see image and video below.
• Squeegee off excess water – draining the metal sheet of all drips, and slightly cool the under-surface of the metal sheet, if possible, by laying it completely level and flat on the coating bench/table.
• Check the temperature of gelatine and carefully reheat in the microwave to reach an ideal temperature of circa 100-120 degrees Fahrenheit. Do not exceed 130 degrees as this makes the gelatine too thin and “runny” for too long a period after pouring.

Note: Excess heat at this stage will damage the gelatine and inhibit the final hardening/polymerisation.

• Lay the uncoated paper sheet completely flat on the metal sheet (check with a spirit level) and dry off all water with paper towels, pressing out any air bubbles. Surround paper with pre-cut magnetic strips or a cut-out magnetic template to retain gelatine only in the area of paper that is to be sensitised and exposed. You can use weights on the magnetic strips, if necessary, only around the edges of the area not to be coated to prevent creeping of liquid gelatine under the magnetic sheet or strips. (The weights are not always necessary, but will allow a cleaner, sharper-edged coating of gelatine).

Note: I tend more recently not to use any magnetic fencing when pouring my gelatine as I can still get good even coverage over my whole print area! You must ensure importantly your paper is perfectly level during this pouring method as any alteration of the gradient will invite natures gravitational force and allow the gelatine to follow its natural way downwards and out!

Method: Coating the Paper with Gelatine

• Pour on 50ml or 60ml max of heated gelatine per A4 sheet quickly onto the centre of the paper and use fine domestic hair comb to spread it to the border edges. Do not move the coated paper for a minimum of 5 minutes. Any bubbles can be removed with a fine comb or a small brush only in the first 1-2 minutes after pouring and before the gelatine sets too hard. Dip coating tools into hot water and clean immediately after each sheet is coated. See the picture and video below.
• After the gelatine has hardened a little, say after about 5-10 minutes ideally, move the metal sheet to the side to let the gel set further. (Allowing it to stay as flat as possible so the gel coating does not spread by gravity into other areas).
• After about minimum of 15 minutes the coated sheet of paper can be removed from the metal sheet for drying – to do this, use a fine blunt knife to score an edge around the paper if secured by the magnetic sheet, allowing the magnetic surround to peel away from the surface of the print – lift magnet strip very carefully. If you have not used the magnetic strip method, this part of the process is much simpler and more efficient in time and with less cleaning to do later!
• Rest the underside of the coated paper on a paper towel to take off any excess water that may still be present on the uncoated side and prepare to secure the paper to a glass sheet for drying.

Important!

Place a sheet of A4 mylar film on a larger A3 size piece of glass and place the A4 coated paper centrally onto the mylar carefully. The damp paper must now be taped with brown gummed adhesive paper tape all around the perimeter edges of the coated paper to dry, to ensure it does not curl or bend during the drying process. Try and avoid taping any of the gelatinised areas with tape as this needs to be cut off in the final print. You should always leave at least ½ ½-inch uncoated border around each A4 coated print. 

Allow to dry flat for about 48 hours, ideally in a cool 60-65% humidity environment.

The coated papers will keep for at least a month, provided they are left secured on a glass sheet to maintain flatness and rigidity. My preference is to use the coated paper within a week or two, as the gelatine appears to lose its “depth” the longer and “drier” it becomes.
The effect this has on the printed image is a distinct lack in contrast and lower density blacks; therefore, always use at the earliest opportunity.

• Allow 0.59ml of Gelatine solution per square inch of coated print.
• This is an approximate guide of circa 60ml per A4+ size print.

Note: Gelatine coating works best in a room with ideal working temperatures, between, say, a minimum of 15 degrees Centigrade, to a maximum of circa 25 degrees Centigrade.
Outside of this range, the gelatine is more difficult to coat evenly, either because it does not solidify quickly or gives an uneven, thinner coating in different areas.

3Making the FAC Sensitiser
To make a total working solution of 100ml FAC sensitiser:

• Weigh 5gm of FAC and mix with 50ml of Water – preferably distilled.
• Add 50ml Acetone (Material Safety Data Sheet) to this mix to make a total solution of 100ml.
• Add 0.6gm Oxalic Acid

It is my understanding from a colleague’s advice that the addition of Oxalic Acid into the FAC (Ferric Amonium Citrate) mix lowers the pH value of the sensitiser appropriately, but in my experience, I have found identical results if you exclude the Oxalic Acid in its entirety.

The lower the % FAC, the higher the contrast; the higher the % FAC, the lower the contrast.

The working FAC solution can last several weeks in a dark brown stoppered bottle, but has a slightly shorter lifespan than the equivalent strength Dichromate solution.

Making the Hydrogen Peroxide Developer total 1000cc:

• Use 100ml of 3% Hydrogen Peroxide
• Mix with 900 cc of room temperature water

Dispose of this solution after every working session.

4Coating the paper with FAC
My simple technique is to pour the estimated working sensitiser directly onto the centre of the gelatined print area and brush quickly and gently in horizontal and vertical directions with a soft 2-inch / 50mm nylon brush. I prefer to use a comparatively large amount of solution per print, as this seems to absorb more fully into my thick coating of 10% strength gelatine. I always coat my sensitiser in dim room lighting, and whilst the paper can dry in this environment, I prefer to dry mine in total darkness.

• Use 0.096ml / sq. inch of sensitiser for coating the Gelatined paper. ie. Circa 10ml per A4+ print.

Since my sensitiser already has a proportion of Acetone in its mixture, I believe this accelerates the drying of the sensitive coating. After only about 30 seconds of brushing, you will feel the FAC sensitiser becoming almost tacky, which is then the time to stop. This tackiness implies the sensitiser is well absorbed in the gelatine coating.

Leave the sensitised sheet to dry for a minimum of 2 hours. I prefer not to accelerate the drying time with a hair dryer but to leave the prints to dry naturally in a darkened room at circa 15-22 degrees Centigrade for at least four to five hours. As in other sensitised procedures, I find it is not a good idea to leave the prints longer than 24 hours before UV exposure and inking takes place. Very soon into the drying process, the sensitised paper becomes sensitive to Ultraviolet light and will fog if left in an openly lit area.

Note: At this stage, the paper is still held nice and flat on a sheet of glass, and this should only be removed after the sensitive coating has dried, and when you are ready for UV exposure. This part of the procedure for storing on glass is helpful because it enables easy storage of coated prints and means they are not physically sitting on top of each other, damaging the delicate coatings and surfaces. 

5Exposing the Print
This part of the procedure I find is identical to any of the other alternative Imaging techniques I use, and requires test strip estimation for the first print, and obviously a UV light source. Ideally, a light source in the region of 365nm to 385nm is the ideal wavelength, but I have had success with even simple equipment such as a domestic facial sun lamp – and if all financial resources fail, the SUN is perfect!

Whilst the length of exposure depends on many factors, I find FAC sensitiser slightly faster in exposure time compared to my original Dichromate exposures based on the same negative. The best negative densities based on my own working situation are those with softer, lower contrast, rather than higher contrast, aiming for a negative with detail in both highlights and shadows.

After exposure, a perfectly exposed print, like the Dichromate process, will show good detail by way of a light brown latent image in almost all areas; this is a good guide to a successful inked print. My average UV exposures are in the region of 1.5 to 5 minutes.

The technique of exposure and development is the magical part of the process that allows Polymerisation of the Gelatine/Image density areas to physically harden the emulsion in the dark areas and soften in the light areas.
Note: Any UV exposure of less than 90 seconds is likely to give less than desirable density in the blacks.

6Developing the Print
Following exposure, the print, or Matrix as it is now known, will need to be developed!

However, the main difference between Dichromate and FAC printing is that in the former, the print is developed in pure water whereas in FAC, this reaction must be crucially created by immersion in a bath of Hydrogen Peroxide. Ironically throughout all my experience with Dichromate Oil Printing I have never regarded the water bath wash as “development”, only as a means of clearing the image of the obvious staining of yellow dichromate.

Somewhat ideally, the initial image staining in the new FAC process is much less than in the Dichromate method, and once “developed” surprisingly shorter wash times can be enjoyed!

After much experimentation with Hydrogen Peroxide, I find the simple formulae of 100ml of 3% solution in 900ml of cold water sufficient for about x4 prints, and standardise with a development time of two minutes.

Without this solution, the process will not work!!! 

• Immersion in this bath is for 2 minutes.

Immediately following development, the print/matrix can be washed in cold running water for 2 minutes.

Note:  A recent amendment to the FAC technique allows even “whiter” whites to be achieved by inserting an additional bath in between the Hydrogen Peroxide development and the Swelling bath.

This can be included in the process as follows:

It has been noted that using FAC on Tongmaster gelatine tends to render the non-exposed whites a pale creamy or ivory tone in the final dried print.

Whilst this does not seem to create any archival issues, if you wish to obtain a “cleaner” white in the highlights then the following bath is recommended.

• Immerse print in a 10% bath of Sodium Metabisulphite for 30 minutes. Room temperature solution is OK.

This important amendment, recently discovered, is in the clearing or cleansing of the print post UV exposure and polymerisation development.  Although the Eco FAC technique stains the print less than a Dichromate sensitised image, I still feel it is best to ensure the image is fully washed of all chemistry. To this end, I have extended my process to include the 30-minute Sodium Metabisulphite bath and then a final cold wash of 30 minutes. This Metabisulphite bath can be omitted if desired, but it does seem to give improved whites more like a fully washed and cleared Dichromate image.

• Following the final cold water rinse the print can be placed in the “Swelling” bath immediately prior to Inking.

7Swelling the Matrix
There are numerous techniques for swelling or preparation of the final matrix, but my tried and tested method relies simply on immediately after the cool water rinse/wash to immerse the print in a heated water bath at no more than 28 degrees Centigrade. This allows my extra-thick coating of gelatine to swell nicely in the appropriate areas, whilst not allowing its softer parts to dissolve too quickly or easily under the excess heat from the water bath.

At this ideal temperature of 28 degrees Centigrade, my images are always quite robust and co-operative under the influence of quite a heavy beating from my Bromoil brushes or my preferred technique using a 2-inch smooth foam roller!

The warm water bath should only be undertaken for a period of around 10 minutes, and I have very few occasions where this needs to be increased.

Note: Extending this bath can reduce the final contrast and density of the inked print!

Usually, after a normal soaking and swelling, the image should appear in quite dramatic 3D relief on a clear background. This is a good sign that both exposure and coating technique have been successfully applied, and you have every chance of an excellent print. Once you are happy that this 3D relief is acceptable, the print can be carefully dabbed dry of excess water with paper towels, and inking can begin immediately. I always ink immediately at this stage, although many of my colleagues often dry the print/matrix at this point and ink at a later date.

8Inking the Print
Unlike my dichromate images, FAC requires a different stiffness of ink, and whilst I try to avoid softening or hardening any of my inks, I find that in the case of my FAC process, Charbonnel 55981 Etching Ink works perfectly straight from the tube.

For the record, my preferred ink of choice for Dichromate images is Lawrence Supplies Carbon Black Letterpress Ink, again available in 150ml tube – interestingly, neither will work for the opposite process, which is most frustrating!

In a similar way to Bromoil or Dichromate inking, a pea sized blob of ink is placed on a smooth glass or tile surface and spread evenly with a spatula to create a thin even coating.
This can either be picked up by brush or roller and applied to the appropriate print.

You will also need to bear in mind that room temperature can affect the inking quality and ability for your ink to work effectively, and ideally this should be again between the room temperature range of circa 15-22 degrees Centigrade.

When I was originally taught the Oil Process by my good friend Radoslaw Brzozowski in Poland, I was taught with a domestic washing-up sponge, which gave the most amazing creative results. However, the Oily process has such versatility that in the end my personal preference was neither sponge nor brush but using a small 2-inch paint roller, which gives me frequently the most amazing high-quality quality almost classical photographic results!

Given that I probably have less patience than the majority, if I cannot ink a complete print in no more than 2-5 minutes, then to me it is unsuccessful and has not worked! If this is the case, then I will alter one of the steps in my process, which is usually due to an error in the negative production stage! However, typically if I have followed all the steps in my described procedure, I am guaranteed a most acceptable image and a high-quality final print.

It is worth noting that, similar to the Bromoil process, prints can be re-immersed in warm water to re-swell the image and ink applied once again in appropriate areas, although I suspect, given the fairly delicate nature of hand-coated gelatine, it will not be as robust as conventional photographic paper.

The Final Print!

On the assumption you have attained a print to your satisfaction, you have now reached one of the most crucial and important stages in the whole process – and that is drying the print!!!

You will realise, given the thickness and density of my inking and coating, we really have a fight on our hands in drying the print, since all the layers of paper, gelatine and ink will attempt to dry on a different time scale. If the picture is left without being securely taped down, then the print will bend, twist dramatically and almost feel like a solid sheet of concrete! Since we need to tame these wild animals, as I call them, once I have finished the inking, I ALWAYS tape my print firmly to a sheet of glass with mylar backing underneath and leave it to dry in as cool a place as possible. This can take a least one to two weeks – but the longer the better, so patience in this area will be well rewarded.

As a final warning, given the strength and power that is amassed in a drying inked print, I have witnessed on several occasions the breaking of a sheet of glass in half by the power of this process – this was probably caused by attempting to dry the print too quickly in too warm an environment!

Happy Oiling!

Dedications:

My thanks to Malin Fabbri for her patience and dedication in the preparation of this article and to my friends and colleagues in the USA and Europe who have helped me with my experiments, namely: Radoslaw Brzozowski, Calvin Grier, Kees Brandenburg, Jacques Kevers, Armand Benedic, Didier Derien, Rene Smets, and Peter Friedrichsen. Finally, my thanks to my friends in The Bromoil Circle of Great Britain, particularly Maija McDougal and Kirk Toft for their support and inspiration during my journey into learning the fantastic Oil Process.

Richard B. Hildred ABIPP is a professional photographer with a career spanning over four decades. He studied creative photography at Nottingham School of Art and Trent Polytechnic in the early 1970s. In 1973, he began work as a medical photographer in the NHS, specialising in ophthalmology. In 1986, he founded Medical Imaging UK Ltd., which grew into one of the UK’s largest independent medical photography services. Since retiring in 2014, Richard has returned to his early passion for alternative photographic techniques, particularly an eco-friendly version of the classical Rawlins Oil Print. He now focuses on personal projects and has curated exhibitions such as Treescapes and Moments in Time, sharing his love of historic processes with new audiences. Richard’s work is also featured in Art and Artists, edition 2, and also in the gallery section of the Bromoil Circle of Great Britain.