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Commenting on the model sets of Thomas and the
Magic Railroad, in Don Angus' article, cinematographer Robbi Hinds had this to say:
“Building miniature sets is a highly specialized
function; for instance, the miniature trees were made specially in London out of brass and then painted, and they look absolutely
real"
We managed to track down the London-based company who were contracted
to build the trees. 4D Modelshop’s Managing Director, Zyg
Jarzembowski was very happy to share with us what made these trees so special. As you will learn, the manufacturing
process that 4D employed is just as fascinating as the final product!
During the spring of 1999, 4D Modelshop received specifications for building
assorted scale model trees to be used in the movie. Approximately one dozen of these customized brass trees were to
be constructed and shipped to the Studio 24 West at 940 Lansdowne, Toronto, where the movie’s model shoot was taking
place. The lot consisted of four each of large English Oaks and Silver Birches, and four medium-sized Silver Birches1. The one requirement was that they were to be constructed out of brass. As Zyg explains:
“The reason that the models were made of brass
was predominantly for rigidity during transit and whilst on set being filmed. In addition, so as not to warp or melt
in the intense lighting during the filming. And of course for realistic super detail when using ‘close up’
photography.”
The artwork and design master
The
process begins with 4D’s Graphics Designer drawing scaled and varied representations of the tree trunks, branches and
foliage using CAD (Computer Aided Design) software. With the desired tree type and size in mind, the design master
layout is fit to the dimensions of a brass sheet, for example 12" x 18". CAD permits that strategic positioning of the graphics
on the layout to minimize brass wastage.
For the larger oak trees, the
artist drew a series of individual leaves to mimic the various, yet distinct foliage shapes and sizes that can be found in
nature.
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| Color-coded individual oak leaves to be used in design master layout. |
Two colors were used in the creation of the design master for the trees:
red and black. As you will see, each color serves a specific purpose in the next step for creating realistic-looking
foliage.
The ‘black’ areas represent where the brass is to
remain intact during the acid etching process. ‘Red’ areas represent where ‘half-etching’
is to take place – that is where only of the brass sheet’s thickness is to be dissolved by the acid from the top
of the brass sheet. In the design master, ‘white’ or transparent areas represent where the brass is to
be completely dissolved. Using the oak leaf example above, the post-etching result will be a recessed leaf with proud veins.
The leaf templates were used repeatedly by the graphics design artist to lay out foliage individually and at
random along the tree branches and fronds, as can be seen in the diagram below.
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| TATMR Oak Tree Design Master: Note random yet strategic layout of the oak foliage on the branches. |
The Phototools
Once
the artist was satisfied with the template’s 2D layout for the tree, the design master is used to produce two phototools
on a photoplotter. One each for the front and reverse side of the brass sheet. The colors used in the design
master determine what features appear on each respective phototool, which could be considered to be a sort of photographic
‘negative’ of the design master. In the example below, a magnified portion of the Silver Birch design master demonstrates
how it is transformed into a set of phototools.
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| Step 2: How the design master's colors determine the layout of the phototools. |
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| Phototool registration mark |
Phototools are used as a template that can be used repeatedly to mass
produce the individual components that make up a tree.
Corresponding registration marks are included on both ‘front’
and ‘back’ phototools so that they will line up properly against the brass sheet during the phototool exposure
process.
The use of registration marks prevents the phototools from being out
of alignment in the phototool machine during the exposure process, which would otherwise result in imperfect components being
produced.
Additional examples of the Magic Railroad tree
phototools
(Right) The ‘front’ phototool for the Silver Birch
foliage, designed to fit on a brass sheet approx. 12” X 13” in size, and .008” thick.
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| click image for full size |
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| click image for full size |
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(Left) The main stem and branches ‘front’ phototool
for the 18” Silver Birch tree. The phototool that was used on the reverse side of the brass sheet is identical. The
brass sheet’s dimensions are 18 inches long by 12 inches wide. The brass sheet used is also a little thicker (0.012”)
to provide robustness.
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(right) Set of ‘front’ and ‘back’
Phototools used for the larger oak trees manufactured for the movie.
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| click image for full size |
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Preparation of Brass Sheet
Before
transferring the design onto the brass sheet with the phototool, a brass sheet is first prepared by cleaning, then coating
both sides of the metal with a liquid photo-resist which dries into a greenish film or emulsion. The ‘negative’
photo-resist is light-sensitive and will chemically change when exposed to the ultra-violet (UV) light of the phototool machine.
This means that transparent areas of the phototool will be chemically altered when exposed to the UV light.
Phototool Exposure
The
‘front’ and ‘back’ phototools are inserted into the phototool exposure machine and
lined up using the registration marks. The ‘back’ phototool is inserted into the phototool machine reversed. The
treated brass sheet is then inserted and secured. The machine is turned on whereupon the UV light performs its work as described
in the previous section.
For this example, we’ll use the foliage for the Silver Birch to
be transferred onto a prepared brass sheet 12” X 13” in size, and .008” thick (see diagram below).
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| Phototool transfer to brass sheet (click image for larger view) |
After exposure, the brass sheet is removed from the phototool machine,
and rinsed in a solution to wash off the unexposed photo-resist, leaving the brass exposed. The black areas of the phototool
blocked the UV light from reaching the photo-resist emulsion. The photo resist that was exposed to the UV light - the
transparent areas of the phototool - has hardened into a protective coat and does not wash off – leaving the perfect
outline of the foliage and branches on both sides of the brass sheet (see figure below). The objective is to protect
these areas from the acid during the etching process.
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| Post phototool exposure (after rinsing) Note green photo resist |
Acid Etching Process
The brass sheet is then placed into an acid bath chamber, where acid is sprayed on both sides of the sheet.
The exposure is timed @30 minutes, so that the acid ‘eats’ through only approximately half of the sheet’s
thickness from each side where the brass is fully exposed. On each side, the hardened photo-resist protects the underlying
brass from the acid. Using the diagram above, the brass sheet will be completely dissolved where their extents are identical
on each side. The resulting product from the full and half etching can be seen in the photo below.
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| The resulting product after acid etching - remnant photo-resist is still visible. |
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(left) Magnified view of post acid etching (same area used in the previous examples). Note
the ‘half-etch’ relief detail of the leaves.
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The remnant photo-resist is then washed away with a solvent, and the
components are ready to be passed on to the craftsman for the actual construction of the trees.
Assembling and Finishing the Trees:
The final stage of assembling, shaping and finishing the tree is a very
intensive and time-consuming process. It did, however ensure that every tree constructed for Thomas and the Magic Railroad
was unique from one another. Zyg describes the process:
"The central tree trunk is made from 12thou (0.3mm) thick etched
brass using the etching process, with additional branches etched loosely to be soldered onto the main body for even more bulk
to the tree."
"The main trunk of the tree had a thick brass rod of 12" soldered
onto the main body with at least 4" overhanging as a 'planting spike' with the remaining 8" running up the trunk and being
well covered with solder for strength. All of one side of the tree was covered with solder and worked and distressed
with the soldering iron to give form and shape.
"The reverse side of the trunk couldn't be soldered as well,
as the front solder would melt and run off. So the reverse was built up with a combination of Hot Glues. Finally,
both sides were covered with 'Plastic Padding', a filler used in the car repair industry, which allows for carving and impressing
of the bark detail."
"The skeleton is then twisted into three dimensions in preparation
for the etched leaves to be soldered on."
(Below)
4D Craftsman, Louis manipulating one of the large oak trees (24” tall and wide) that were constructed
for Thomas and the Magic Railroad. The myriad individual leaf fronds were
all manually soldered onto the branches.
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| click image for larger view |
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“The etched frond (tree shape) then painstakingly had each
individual branch of leaves soldered onto the main armature. Glue would not suffice, as it then had to be tweaked and
bent into a 3D shape and required strength whilst it was being manipulated.”
“The final stage was to distress the trunks and hand paint
the thousands of leaves, dry brushing as we went for even more detail”
“Several coats of paint/speckling/dry brushing etc and there
you have it.”
Below, the finished Silver Birch tree that stands 18” tall and
approx 10” wide.
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| click image for larger view |
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| 4Ds Silver Birches as seen in this scene in TATMR (left), and being upstaged by Diesel-10 (right) |
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| Henry trundling past a few of 4Ds large oak trees |
Thanks and Acknowledgements
We wish to sincerely thank 4D’s Zyg
Jarzembowski and Andy Feron for their insight, photographs
and support for helping us compile this article. My thanks also to 4D's Ben
for his prompt assistance for providing me with a few scans. It was certainly an educational process for which we
are very grateful. Readers will undoubtedly appreciate the skills and hard work that went into this
contribution to Thomas and the Magic Railroad.
I would like to also extend my thanks once again to Dave Axford for his recollections of seeing - and admiring these sundry trees :)
All article Photos © 4D Modelshop
and courtesy to SiF, diagrams and article text by James Gratton.
About 4D Modelshop Limited
4D Modelshop has
an extensive stock of quality model making materials, tools and accessories. They offer a wide range of model making services:
acid etching, white metal and resin casting, laser cutting, dry transfers, waterslides and custom scenic builds. 4D also manufacture
quality models and accessories used for architectural design, film and television.
You can visit 4D Modelshop
in person at their walk-in store located at The Arches, 120 Leman Street, London, or visit their website. Post-Secondary Student Discounts are offered for in-store and
online purchases. Be sure to check out their sponsored professional model making courses offered at local educational institutions.
Special Notice:
Zyg would like to extend an open invitation to all SiF visitors to attend
‘New Blades’, 4D’s annual show for graduates in modelmaking
to take place on the 12 & 13 June, 2008 in London.. Details can be found here:
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