REPROGRAPHICS IN THE ROYAL ARSENAL
REPROGRAPHICS IN THE ROYAL ARSENAL
The Reprographics section in the Royal Arsenal moved down from the Red Barracks in the early 1970s into a purpose-built two-storey building known as Building 9. Building 9 lay in an east-to-west direction. The main entrance was at the east end. Although the west end did have an entrance, it was not allowed to be used and was only there as a fire exit. There was a large steel concertina door on the northwest corner. This door was supposed to be for goods and stores coming in and out, but a lot of the staff used to come in and out this way, much to the annoyance of the management. A corridor ran from the east entrance to the west entrance. Halfway down this corridor, another corridor crossed it, leading from the Offset Lithographic room on the south side to the Dyeline room on the north side. Then, just before the west entrance, another corridor crossed, leading from the collating room on the south side to the steel concertina door on the north side. Just inside the east and west entrances were a set of stairs leading up. The layout upstairs was similar to that of downstairs. As we came in through the main east entrance, there is a door to the left leading into the Offset room. To the right, there is the main reception office. A corridor just past the reception led down to three further offices. These offices were where the main managers and secretaries of the reprographics sections were. The Reprographic unit of Building 9 was made up of several sections.
PHOTOGRAPHIC DEPARTMENT
Taking up the whole of the south side of the top floor was the photographic section and darkrooms. Most of the negatives and positives used in the other reprographic departments came from here. The photographers often went out on field trips to photograph projects, such as a tank or weapon being fired. In later years, video recording was also used. They had their own video equipment, which included editing, mixing, and sound desks. These were as good as what the television companies were using at the time, so the work produced was of a very high standard. A lot of their work involved photographing typed text and line-drawn A4 diagrams for the Offset printing section downstairs. The cameras used for this were table, gallery, and hole-in-the-wall cameras. The photographic section was run independently and had its own managers and offices on the top floor at the west end of the building.
35MM, MICROFILM AND MICROFICHE SECTION
The 35mm Microfilm section was housed in a room at the west end of the top floor. 35mm was a storage and reference method. Rather than keeping one page of everything that was printed in the repro sections, the page was photographed on a 35mm machine, producing a 35mm negative. This was then set into an index card, which was hole-punched with the negative's information. This was then stored away for future reference, thus taking up less room and being more durable than a printed page. In a room across the corridor on the northwest corner was the microfiche section. Microfiche was also used for storage and reference, but the film was 4” x 5” and was not set into an index card. Microfiche could hold up to 100 images. These two sections were not run by the photographic section but came under the reprographics section downstairs. The rest of the south side of the top floor was where the Microfilm and Microfiche were stored/filed and where the typists were.
OLD SILK SCREEN SECTION & NEW REST ROOM
If you were to walk from the main entrance down the main corridor to the corridor that crosses at the far end, turn right, then left through the first door, you would walk into the new restroom where the gelatin stencils were exposed on an ultraviolet light box for the newer screen-printing section. In the seventies, this room was the old Screen Printing section. The old screen printers used real silk taffeta in their wooden frames. Laying green stencil paper over an original made the stencils. Using a scalpel, the green stencil paper was cut by using the tracing method, following the original underneath. This was very time-consuming, and you had to be very skillful and patient. The green stencil paper was then ironed onto the underside of the silk screen. All of the printing was done by hand. The other process used in this room involved two tables, about ten feet long, that had a hand-turned conveyor belt on them. The conveyor was slowly turned and coated evenly with liquid gelatine. The gelatine was then allowed to set. Once set, it had an image produced on it. This image was then inked up, and a sheet of paper was laid over it; the paper was then rolled with a roller to transfer the image onto the paper. The only trouble with this job was that you had to go to the slaughterhouse at the bottom of Shooters Hill to get animal parts, then boil them down to make the gelatine. By the late 1980s, it was decided that the staff who worked on the printing machinery should not be eating their lunch or drinking tea at break times at their machines. A new Screen Printing section had been set up over the road in Building 7. So, this room had been cleared and was now only used to store work waiting to go into the collating room or work that had been finished and was waiting to be sent off. It was then decided that this room should be turned into a rest room.
PAPER STORES AND RESTROOM / DARTS ROOM
The room adjoining was a storeroom where the new reams of paper were stored before being printed on. It was also the restroom for the labourers of the building, and where most of the younger staff went at break time and dinnertime to play darts. Our main dart team won the top team trophy in the Arsenal. In between these two rooms was possibly the smallest room in Building 9. It was about five feet wide and fifteen feet long. It had three sinks in it; each sink was about three feet wide and four feet long, and these were for the developing and washing of the later type of gelatine stencils for the newer Screen Printing Section.
MONTAGE SECTION
Come back out into the corridor and turn right; we go into the collating room. Turn left, and you are into what was arguably the main room and section of the reprographic unit. We are now in the montage section. This is where the negatives from the photographers are first checked and spotted out. Processes where any black areas of the negative that are letting light through are spotted (painted) out. The negative is then striped or masked out. This is where a card frame is made around the negative, and registration marks are worked out and marked onto the card. Halftone and line diagrams are stripped or set into the main negative at this point.
PLATE MAKING SECTION
The negative was then taken over to the plate-making section. The negative was placed onto an ultraviolet light-sensitive aluminum printing plate; the registration marks on the card were lined up with the edge of the plate. The plate was then placed into a vacuum frame and exposed to ultraviolet light for about three minutes, then taken out of the frame, and the negative was removed. The plate was then laid on a flat worktop where red developer was poured on and rubbed all over the plate until an image appeared. The surplus developer was then washed off under water. Gum Arabic was wiped on the plate and buff-dried to stop the plate from oxidizing.
Other types of printing plates made here were Photo Direct (P.D.) plates. This is where an original—being text, line drawing, or halftone—is placed on a vacuum frame directly below the P.D. camera lens. The P.D. camera takes a photograph of the original and produces that image directly onto a plastic or paper plate. The Brunning was also a small plate-making machine that made paper plates. These plates did not last as long on the printing presses as the aluminum ones and were not reusable. An assistant chief photo printer supervised the whole montage area.
OFFSET LITHOGRAPHIC SECTION.
As you move through the montage area, you enter the Offset Lithographic area. One of the smaller printing machines in this area is the Rotor Print tabletop machine, which is what the name implies: a small machine that sits on a table. This machine used only paper or plastic printing plates. There was a Multigraph machine, which printed its image from movable lead type, making it a letterpress machine. It was used mostly for short runs of work, such as letter headings and small cards. The next machine was a Multilith systems machine. This machine could have the number of prints programmed into it, could put its own printing plates on, print the job, and then remove the plate and go on to the next one. Though it was quick, the registration was not as good as other machines. Next to this machine was the Davidson Perfector Press, the largest machine of the offset litho section, about 8ft long, 4ft wide, and over 6ft high. This was an offset lithographic machine that could print both sides of the paper at the same time, had a stream feed, and chained delivery. Because of this, it could produce the work very quickly and was best suited to large run jobs. It was a good machine, but only three people ever learnt to set it up and work it. Because of this and the fact it ate the work so quickly, it was not used a lot. The next machines were the Multilith 1250, later updated to 1350. These machines printed mostly on A4 size paper. They were the mainstay of the print section. There were about ten of these machines. There were four 1850s, later updated to 1860. These machines were similar to the 1250/1350 but were twice the size. They usually printed on A3 size paper and did most of the colour work. The last offset litho machine was the RotorPrint R 30/90. It was not used a great deal, and for this reason, was not kept very long. This was a shame, as it was probably the best machine in the room. Towards the last years in building 9, an A3 Ryobi machine was brought in. It was very similar to the 1860. You generally had to be a Photo Printer Grade 1 to work a 1250/1350 and a Leading Operator to work an 1850/1860 and the Davidson Perfector Press. You also had to be a Leading Operator to be able to print in colour on any of these machines. This section had two Assistant Chief Photo Printers (A.C.P.).
COLLATING ROOM.
If we now turn and walk back through the Lithographic and montage sections, we go back into the Collating room. In this room, the printed pages were gathered, collated, pinned, stapled, bound, and glued, turning single pages into leaflets, pamphlet books, and manuals. There were two Ordainer Collating machines, though a lot of the collating was done by hand; three wire pinning machines; several electric and manual staplers; two four-hole and single-hole punch/drilling machines; a strapping machine for sealing boxes; and a comb binding machine. There was also a frame press for gluing and making pads. This section also had two A.C.P.s.
DYELINE COPYING SECTION.
If we now go to the north side of the building, we come to the room that was commonly known as the dyeline room and later on, the copying room. It was called this after the three large dyeline machines that took up one end of the room. These machines, with their delivery tables, were about 20ft long, 7ft wide, and 7ft tall. They had to have a vent pipe to the outside of the building, as they used ammonia to develop the image on the paper. The image was taken from one or more transparencies. The diazole paper the image was transferred onto was about 5ft wide and came on rolls. The final print was mainly used for plans and was slightly bluish in colour. This is where the name "Blue Print" comes from. Some of the 35mm aperture card machines were in this room. These machines used to fix the 35mm films into special hole-punched cards. This is also the room where the photocopiers started to appear, just one Xerox copier at first, but by the end of the 1980s, this room was full of several makes of photocopiers. They started to take the work away from the offset department, though the quality and registration of the print was not as good as the offsets. This section also had an outstation in building 22 and in the Royal Arsenal East.
NEW SCREEN PRINTING SECTION
If we now go out through the main entrance of building 9, across the road there is an entrance leading into building 7. The section in this building that we are interested in is the New Screen Printing Section. It is sited roughly in the center of the building. There were no windows apart from the skylight in the roof about 30ft above.
Apart from the dyeline, this process produced the largest prints of all the departments. Printing on 30”x 40” admiralty chart to produce posters for the services. Drawing frames were also produced for the illustrators on this machine, printing on a translucent plastic known as Ozatex.
The screen-printing machine was a Theme 2025; it was about 30ft in length and 10ft wide. To go through the process of screen-printing, first a set of transparencies were drawn up by the illustrators in building 22, one transparency for each colour to be printed.
The transparency was taken over to the ultra-violet light box in building 9. The transparency was laid face down on the light box, then a red gelatine film with a clear plastic backing was laid matt side down over the transparency, the lid of the light box was closed and the vacuum turned on. This was to make sure the transparency and the gelatine film were pressed together so that no light could get between them.
The exposure was for about 3 minutes; at the end of this time, the vacuum was turned off and the film and transparency removed. The red gelatine film was then taken into the small room with the three sinks in. The film was placed in the first sink where a developer was poured over it, agitating the film in the developer for about 2 minutes until the red film turned slightly white.
The film was then put in the second sink of warm water; as the film is agitated, the area not exposed to the ultra-violet light gradually washes away, whereas the area exposed to the ultra-violet light remains.
When the unexposed areas are clear, the film is taken out of the warm water and placed in the next sink with cold water in it; this helps to fix the image and stop any more of the gelatine dissolving. The gelatine film is then rolled up and taken back over to building 7.
In the screen-printing room, the film is placed in a water trough and washed once more to freshen it up, then it is placed face up (gelatine up) on a table. A 6ft x 5ft nylon meshed screen is then lowered carefully down onto it, so that the gelatine stencil is positioned squarely towards the top right-hand corner.
Some paper is laid over the mesh and then rolled with a roller to expel the excess water and press the gelatine into the mesh. Brown paper tape is stuck down on all four sides, half on the nylon mesh and half up the sides of the metal frame. This will stop the ink seeping out round the edge of the screen.
The screen is now left for a couple of hours to dry. When thoroughly dry, the clear backing on the gelatine film can be carefully peeled off. The meshed area of the screen is now supported off the table so that a thick red liquid screen block can be spread over the open areas of nylon mesh between the red gelatine stencil and the brown paper tape; this is done on both sides of the screen, with a piece of card using a squeegee action.
The red screen block only takes a couple of minutes to dry. The screen is now taken over to the Theme printing machine. The metal frame of the screen is placed into two horizontal moveable metal bars on the printing machine/printing frame.
A foot pedal is pressed, which slides a table out from the machine. A sheet of the 30 x 40 admiralty chart is placed on the table, making sure the leading edge and right-hand edge are butted up to the registration stops. The remaining area of the table that the admiralty chart is not covering has to be masked out with paper.
Now the black positive film is laid onto the admiralty chart, making sure it is positioned where we would like it to be printed. When the black positive is correctly positioned, it is held in place with masking tape on the corners.
The positive of the colour we intend to print (the one we made the stencil from that is on the machine) is placed over the black positive, making sure the registration marks on the two positives line up; the second positive is now held in place with masking tape.
The foot pedal is pressed and the table moves into the machine, under the screen, and the screen lowers down onto the table. If we now look down onto the screen, we can see through the stencil to the black and colour positives below.
The screen is now moved around on the bars so that the open areas of the stencil register (match up) with the coloured positive below; when we are happy with the positioning, the stencil's frame is clamped to the two metal bars and the two metal bars are clamped to the machine's printing frame. The table can now be brought out again and the two positives removed.
The next step is to mix the printing ink to the correct colour. About 95% of the colours that are printed have to be specially mixed from 12 base colours. Usually, the illustrators send over a colour swatch with the positives, or a British Standard number quoted; sometimes an article or a piece of something will turn up and the colour has to be replicated in ink.
Sometimes the illustrators come over themselves to watch the ink being matched and change the shade or colour as the ink is being mixed. A colour chart and measuring system can be used for mixing the ink, though it was normally mixed by eye because most of the colours chosen were too far removed from those on the colour chart.
Thinners are mixed with the ink to make it a similar consistency to that of a liquid paint, so that it will pass through the mesh. Retarda is also used; it is a form of thinners but gives the ink a longer drying time.
The last thing that is sometimes mixed with the ink is Reducing Base; this is a clear base with a similar consistency of treacle. It makes the ink more translucent, so if the ink with the Reducing Base in is printed over another ink, the ink underneath will change the colour of the top ink. While the ink is being mixed, the two print drying units are switched on. This gives them time to reach the right temperature for when we are ready to print.
Back at the Theme 2025, it’s time for the squeegee and flood coater to be clamped onto the machine's transit bars. These bars are what raise, lower, and move the squeegee and flood coater back and forth across the screen.
A trolley load of admiralty charts is brought up close to the printing machine. The ink is poured into the near end of the screen, and a sheet of chart is placed onto the machine's table, making sure it is butted up to the front and side registration stops. The foot pedal is depressed, activating the vacuum on the table to hold the chart in place. The table moves in under the screen.
The squeegee and flood coater move to the back of the screen, the flood coater taking the ink across the screen with it. The screen lowers to the table, and the flood coater and squeegee move to the front of the screen, with the squeegee spreading the ink and squeegeeing it through the screen where the open areas of the stencil are, onto the Admiralty chart.
The screen now raises; grippers come up and hold the chart while the vacuum on the table switches off and the table slides out. The chart is now released from the grippers and floats down to a conveyor belt. This belt brings the chart out from under the machine onto a second conveyor belt, which takes the chart into the first dryer that blows hot air of about 85°C onto the paper, drying the ink within seconds.
The second dryer is actually a cooler blowing cold air to cool the chart down. The chart carries along the conveyor until it drops into a delivery tray. While this piece of chart has been on this journey, six to eight other sheets have all been placed on by hand and are going through the various stages of the journey.
For every colour on the finished print, the whole process has to be repeated, and the admiralty chart has to make this journey. Though six is the average amount of colours used for a printed poster, some have nine colours or more. This process continues until the job's total plus extras for wastage is reached, whether it be hundreds, thousands, or tens of thousands.
When a particular colour has finished being printed, the screen has to be cleaned back to nylon mesh. First, the ink is scraped out of the screen and replaced into the tin it came from so it can be used again. The squeegee and flood coater are removed and cleaned with general-purpose cleaners. Next, the screen is washed with general-purpose cleaner to remove the remainder of the ink.
The screen is then taken over and placed on end in a washdown trough. The red screen block is washed off with a jet of water from a hose and a scrubbing brush; this also takes off the brown paper tape. Gelatine stencil remover is poured and scrubbed over the red gelatine stencil, then left for 10 minutes. The gelatine now starts to bubble and is also washed off with water and scrubbed.
The screen is now clean but has to be degreased. A white degreasing paste is scrubbed over the entire screen on both sides and left. After 15 minutes, the degreasing paste is washed off with a jet of water and the screen left to dry, when it will be ready to use again.
In the late 1970s and 1980s, Building 9 was the largest M.O.D print section in the south; it also was in charge of several outstations from small one-person posts in building 22 to posts at the Royal Arsenal East.
The Reprographics section in the Royal Arsenal moved down from the Red Barracks in the early 1970s into a purpose-built two-storey building known as Building 9. Building 9 lay in an east-to-west direction. The main entrance was at the east end. Although the west end did have an entrance, it was not allowed to be used and was only there as a fire exit. There was a large steel concertina door on the northwest corner. This door was supposed to be for goods and stores coming in and out, but a lot of the staff used to come in and out this way, much to the annoyance of the management. A corridor ran from the east entrance to the west entrance. Halfway down this corridor, another corridor crossed it, leading from the Offset Lithographic room on the south side to the Dyeline room on the north side. Then, just before the west entrance, another corridor crossed, leading from the collating room on the south side to the steel concertina door on the north side. Just inside the east and west entrances were a set of stairs leading up. The layout upstairs was similar to that of downstairs. As we came in through the main east entrance, there is a door to the left leading into the Offset room. To the right, there is the main reception office. A corridor just past the reception led down to three further offices. These offices were where the main managers and secretaries of the reprographics sections were. The Reprographic unit of Building 9 was made up of several sections.
PHOTOGRAPHIC DEPARTMENT
Taking up the whole of the south side of the top floor was the photographic section and darkrooms. Most of the negatives and positives used in the other reprographic departments came from here. The photographers often went out on field trips to photograph projects, such as a tank or weapon being fired. In later years, video recording was also used. They had their own video equipment, which included editing, mixing, and sound desks. These were as good as what the television companies were using at the time, so the work produced was of a very high standard. A lot of their work involved photographing typed text and line-drawn A4 diagrams for the Offset printing section downstairs. The cameras used for this were table, gallery, and hole-in-the-wall cameras. The photographic section was run independently and had its own managers and offices on the top floor at the west end of the building.
35MM, MICROFILM AND MICROFICHE SECTION
The 35mm Microfilm section was housed in a room at the west end of the top floor. 35mm was a storage and reference method. Rather than keeping one page of everything that was printed in the repro sections, the page was photographed on a 35mm machine, producing a 35mm negative. This was then set into an index card, which was hole-punched with the negative's information. This was then stored away for future reference, thus taking up less room and being more durable than a printed page. In a room across the corridor on the northwest corner was the microfiche section. Microfiche was also used for storage and reference, but the film was 4” x 5” and was not set into an index card. Microfiche could hold up to 100 images. These two sections were not run by the photographic section but came under the reprographics section downstairs. The rest of the south side of the top floor was where the Microfilm and Microfiche were stored/filed and where the typists were.
OLD SILK SCREEN SECTION & NEW REST ROOM
If you were to walk from the main entrance down the main corridor to the corridor that crosses at the far end, turn right, then left through the first door, you would walk into the new restroom where the gelatin stencils were exposed on an ultraviolet light box for the newer screen-printing section. In the seventies, this room was the old Screen Printing section. The old screen printers used real silk taffeta in their wooden frames. Laying green stencil paper over an original made the stencils. Using a scalpel, the green stencil paper was cut by using the tracing method, following the original underneath. This was very time-consuming, and you had to be very skillful and patient. The green stencil paper was then ironed onto the underside of the silk screen. All of the printing was done by hand. The other process used in this room involved two tables, about ten feet long, that had a hand-turned conveyor belt on them. The conveyor was slowly turned and coated evenly with liquid gelatine. The gelatine was then allowed to set. Once set, it had an image produced on it. This image was then inked up, and a sheet of paper was laid over it; the paper was then rolled with a roller to transfer the image onto the paper. The only trouble with this job was that you had to go to the slaughterhouse at the bottom of Shooters Hill to get animal parts, then boil them down to make the gelatine. By the late 1980s, it was decided that the staff who worked on the printing machinery should not be eating their lunch or drinking tea at break times at their machines. A new Screen Printing section had been set up over the road in Building 7. So, this room had been cleared and was now only used to store work waiting to go into the collating room or work that had been finished and was waiting to be sent off. It was then decided that this room should be turned into a rest room.
PAPER STORES AND RESTROOM / DARTS ROOM
The room adjoining was a storeroom where the new reams of paper were stored before being printed on. It was also the restroom for the labourers of the building, and where most of the younger staff went at break time and dinnertime to play darts. Our main dart team won the top team trophy in the Arsenal. In between these two rooms was possibly the smallest room in Building 9. It was about five feet wide and fifteen feet long. It had three sinks in it; each sink was about three feet wide and four feet long, and these were for the developing and washing of the later type of gelatine stencils for the newer Screen Printing Section.
MONTAGE SECTION
Come back out into the corridor and turn right; we go into the collating room. Turn left, and you are into what was arguably the main room and section of the reprographic unit. We are now in the montage section. This is where the negatives from the photographers are first checked and spotted out. Processes where any black areas of the negative that are letting light through are spotted (painted) out. The negative is then striped or masked out. This is where a card frame is made around the negative, and registration marks are worked out and marked onto the card. Halftone and line diagrams are stripped or set into the main negative at this point.
PLATE MAKING SECTION
The negative was then taken over to the plate-making section. The negative was placed onto an ultraviolet light-sensitive aluminum printing plate; the registration marks on the card were lined up with the edge of the plate. The plate was then placed into a vacuum frame and exposed to ultraviolet light for about three minutes, then taken out of the frame, and the negative was removed. The plate was then laid on a flat worktop where red developer was poured on and rubbed all over the plate until an image appeared. The surplus developer was then washed off under water. Gum Arabic was wiped on the plate and buff-dried to stop the plate from oxidizing.
Other types of printing plates made here were Photo Direct (P.D.) plates. This is where an original—being text, line drawing, or halftone—is placed on a vacuum frame directly below the P.D. camera lens. The P.D. camera takes a photograph of the original and produces that image directly onto a plastic or paper plate. The Brunning was also a small plate-making machine that made paper plates. These plates did not last as long on the printing presses as the aluminum ones and were not reusable. An assistant chief photo printer supervised the whole montage area.
OFFSET LITHOGRAPHIC SECTION.
As you move through the montage area, you enter the Offset Lithographic area. One of the smaller printing machines in this area is the Rotor Print tabletop machine, which is what the name implies: a small machine that sits on a table. This machine used only paper or plastic printing plates. There was a Multigraph machine, which printed its image from movable lead type, making it a letterpress machine. It was used mostly for short runs of work, such as letter headings and small cards. The next machine was a Multilith systems machine. This machine could have the number of prints programmed into it, could put its own printing plates on, print the job, and then remove the plate and go on to the next one. Though it was quick, the registration was not as good as other machines. Next to this machine was the Davidson Perfector Press, the largest machine of the offset litho section, about 8ft long, 4ft wide, and over 6ft high. This was an offset lithographic machine that could print both sides of the paper at the same time, had a stream feed, and chained delivery. Because of this, it could produce the work very quickly and was best suited to large run jobs. It was a good machine, but only three people ever learnt to set it up and work it. Because of this and the fact it ate the work so quickly, it was not used a lot. The next machines were the Multilith 1250, later updated to 1350. These machines printed mostly on A4 size paper. They were the mainstay of the print section. There were about ten of these machines. There were four 1850s, later updated to 1860. These machines were similar to the 1250/1350 but were twice the size. They usually printed on A3 size paper and did most of the colour work. The last offset litho machine was the RotorPrint R 30/90. It was not used a great deal, and for this reason, was not kept very long. This was a shame, as it was probably the best machine in the room. Towards the last years in building 9, an A3 Ryobi machine was brought in. It was very similar to the 1860. You generally had to be a Photo Printer Grade 1 to work a 1250/1350 and a Leading Operator to work an 1850/1860 and the Davidson Perfector Press. You also had to be a Leading Operator to be able to print in colour on any of these machines. This section had two Assistant Chief Photo Printers (A.C.P.).
COLLATING ROOM.
If we now turn and walk back through the Lithographic and montage sections, we go back into the Collating room. In this room, the printed pages were gathered, collated, pinned, stapled, bound, and glued, turning single pages into leaflets, pamphlet books, and manuals. There were two Ordainer Collating machines, though a lot of the collating was done by hand; three wire pinning machines; several electric and manual staplers; two four-hole and single-hole punch/drilling machines; a strapping machine for sealing boxes; and a comb binding machine. There was also a frame press for gluing and making pads. This section also had two A.C.P.s.
DYELINE COPYING SECTION.
If we now go to the north side of the building, we come to the room that was commonly known as the dyeline room and later on, the copying room. It was called this after the three large dyeline machines that took up one end of the room. These machines, with their delivery tables, were about 20ft long, 7ft wide, and 7ft tall. They had to have a vent pipe to the outside of the building, as they used ammonia to develop the image on the paper. The image was taken from one or more transparencies. The diazole paper the image was transferred onto was about 5ft wide and came on rolls. The final print was mainly used for plans and was slightly bluish in colour. This is where the name "Blue Print" comes from. Some of the 35mm aperture card machines were in this room. These machines used to fix the 35mm films into special hole-punched cards. This is also the room where the photocopiers started to appear, just one Xerox copier at first, but by the end of the 1980s, this room was full of several makes of photocopiers. They started to take the work away from the offset department, though the quality and registration of the print was not as good as the offsets. This section also had an outstation in building 22 and in the Royal Arsenal East.
NEW SCREEN PRINTING SECTION
If we now go out through the main entrance of building 9, across the road there is an entrance leading into building 7. The section in this building that we are interested in is the New Screen Printing Section. It is sited roughly in the center of the building. There were no windows apart from the skylight in the roof about 30ft above.
Apart from the dyeline, this process produced the largest prints of all the departments. Printing on 30”x 40” admiralty chart to produce posters for the services. Drawing frames were also produced for the illustrators on this machine, printing on a translucent plastic known as Ozatex.
The screen-printing machine was a Theme 2025; it was about 30ft in length and 10ft wide. To go through the process of screen-printing, first a set of transparencies were drawn up by the illustrators in building 22, one transparency for each colour to be printed.
The transparency was taken over to the ultra-violet light box in building 9. The transparency was laid face down on the light box, then a red gelatine film with a clear plastic backing was laid matt side down over the transparency, the lid of the light box was closed and the vacuum turned on. This was to make sure the transparency and the gelatine film were pressed together so that no light could get between them.
The exposure was for about 3 minutes; at the end of this time, the vacuum was turned off and the film and transparency removed. The red gelatine film was then taken into the small room with the three sinks in. The film was placed in the first sink where a developer was poured over it, agitating the film in the developer for about 2 minutes until the red film turned slightly white.
The film was then put in the second sink of warm water; as the film is agitated, the area not exposed to the ultra-violet light gradually washes away, whereas the area exposed to the ultra-violet light remains.
When the unexposed areas are clear, the film is taken out of the warm water and placed in the next sink with cold water in it; this helps to fix the image and stop any more of the gelatine dissolving. The gelatine film is then rolled up and taken back over to building 7.
In the screen-printing room, the film is placed in a water trough and washed once more to freshen it up, then it is placed face up (gelatine up) on a table. A 6ft x 5ft nylon meshed screen is then lowered carefully down onto it, so that the gelatine stencil is positioned squarely towards the top right-hand corner.
Some paper is laid over the mesh and then rolled with a roller to expel the excess water and press the gelatine into the mesh. Brown paper tape is stuck down on all four sides, half on the nylon mesh and half up the sides of the metal frame. This will stop the ink seeping out round the edge of the screen.
The screen is now left for a couple of hours to dry. When thoroughly dry, the clear backing on the gelatine film can be carefully peeled off. The meshed area of the screen is now supported off the table so that a thick red liquid screen block can be spread over the open areas of nylon mesh between the red gelatine stencil and the brown paper tape; this is done on both sides of the screen, with a piece of card using a squeegee action.
The red screen block only takes a couple of minutes to dry. The screen is now taken over to the Theme printing machine. The metal frame of the screen is placed into two horizontal moveable metal bars on the printing machine/printing frame.
A foot pedal is pressed, which slides a table out from the machine. A sheet of the 30 x 40 admiralty chart is placed on the table, making sure the leading edge and right-hand edge are butted up to the registration stops. The remaining area of the table that the admiralty chart is not covering has to be masked out with paper.
Now the black positive film is laid onto the admiralty chart, making sure it is positioned where we would like it to be printed. When the black positive is correctly positioned, it is held in place with masking tape on the corners.
The positive of the colour we intend to print (the one we made the stencil from that is on the machine) is placed over the black positive, making sure the registration marks on the two positives line up; the second positive is now held in place with masking tape.
The foot pedal is pressed and the table moves into the machine, under the screen, and the screen lowers down onto the table. If we now look down onto the screen, we can see through the stencil to the black and colour positives below.
The screen is now moved around on the bars so that the open areas of the stencil register (match up) with the coloured positive below; when we are happy with the positioning, the stencil's frame is clamped to the two metal bars and the two metal bars are clamped to the machine's printing frame. The table can now be brought out again and the two positives removed.
The next step is to mix the printing ink to the correct colour. About 95% of the colours that are printed have to be specially mixed from 12 base colours. Usually, the illustrators send over a colour swatch with the positives, or a British Standard number quoted; sometimes an article or a piece of something will turn up and the colour has to be replicated in ink.
Sometimes the illustrators come over themselves to watch the ink being matched and change the shade or colour as the ink is being mixed. A colour chart and measuring system can be used for mixing the ink, though it was normally mixed by eye because most of the colours chosen were too far removed from those on the colour chart.
Thinners are mixed with the ink to make it a similar consistency to that of a liquid paint, so that it will pass through the mesh. Retarda is also used; it is a form of thinners but gives the ink a longer drying time.
The last thing that is sometimes mixed with the ink is Reducing Base; this is a clear base with a similar consistency of treacle. It makes the ink more translucent, so if the ink with the Reducing Base in is printed over another ink, the ink underneath will change the colour of the top ink. While the ink is being mixed, the two print drying units are switched on. This gives them time to reach the right temperature for when we are ready to print.
Back at the Theme 2025, it’s time for the squeegee and flood coater to be clamped onto the machine's transit bars. These bars are what raise, lower, and move the squeegee and flood coater back and forth across the screen.
A trolley load of admiralty charts is brought up close to the printing machine. The ink is poured into the near end of the screen, and a sheet of chart is placed onto the machine's table, making sure it is butted up to the front and side registration stops. The foot pedal is depressed, activating the vacuum on the table to hold the chart in place. The table moves in under the screen.
The squeegee and flood coater move to the back of the screen, the flood coater taking the ink across the screen with it. The screen lowers to the table, and the flood coater and squeegee move to the front of the screen, with the squeegee spreading the ink and squeegeeing it through the screen where the open areas of the stencil are, onto the Admiralty chart.
The screen now raises; grippers come up and hold the chart while the vacuum on the table switches off and the table slides out. The chart is now released from the grippers and floats down to a conveyor belt. This belt brings the chart out from under the machine onto a second conveyor belt, which takes the chart into the first dryer that blows hot air of about 85°C onto the paper, drying the ink within seconds.
The second dryer is actually a cooler blowing cold air to cool the chart down. The chart carries along the conveyor until it drops into a delivery tray. While this piece of chart has been on this journey, six to eight other sheets have all been placed on by hand and are going through the various stages of the journey.
For every colour on the finished print, the whole process has to be repeated, and the admiralty chart has to make this journey. Though six is the average amount of colours used for a printed poster, some have nine colours or more. This process continues until the job's total plus extras for wastage is reached, whether it be hundreds, thousands, or tens of thousands.
When a particular colour has finished being printed, the screen has to be cleaned back to nylon mesh. First, the ink is scraped out of the screen and replaced into the tin it came from so it can be used again. The squeegee and flood coater are removed and cleaned with general-purpose cleaners. Next, the screen is washed with general-purpose cleaner to remove the remainder of the ink.
The screen is then taken over and placed on end in a washdown trough. The red screen block is washed off with a jet of water from a hose and a scrubbing brush; this also takes off the brown paper tape. Gelatine stencil remover is poured and scrubbed over the red gelatine stencil, then left for 10 minutes. The gelatine now starts to bubble and is also washed off with water and scrubbed.
The screen is now clean but has to be degreased. A white degreasing paste is scrubbed over the entire screen on both sides and left. After 15 minutes, the degreasing paste is washed off with a jet of water and the screen left to dry, when it will be ready to use again.
In the late 1970s and 1980s, Building 9 was the largest M.O.D print section in the south; it also was in charge of several outstations from small one-person posts in building 22 to posts at the Royal Arsenal East.