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(pag 24)
In the year 2001 the
Valencia City Council chose, after a disputed selection,
the studio General de Producciones y Diseño (GDP)
to carry out their most ambitious cultural project:
to design and realize the design of the city’s
History Museum. As a site for the museum they chose
an old water deposit built by Ildefonso Cerdá
in the mid-19th century , known as the Hipóstila
room. The main part of the audiovisual presentation
in Valencia’s History Museum consists of a series
of projections within interactive installations. There
are 12 audiovisual segments that will be projected in
the museum. Each of these shows scenes from different
eras in the history of the city, since its origins in
the roman period until the turn of the 20th century.
The visitors will be able to look into the past, as
if through a window, into 12 different moments in history.
Each segment is divided into 5 differently themed clips
or sequences, with an average length of 2 minutes and
which can be selected at random.
HD to increase realism
In order to achieve a greater feeling of realism and
make the projections more spectacular, HD was used in
all the phases of the process. Using HD provides not
only greater resolution but also provides with the opportunity
to work with special effects on lighting and composition.
The starting point was the use of the Sony F-900 HDCAM
, with the peculiarity that we shot with the camera
at a right angle from the horizontal line of the frame.
This way of filming is determined by the size of the
screen in the museum, which was 3x 3’57, that
is a 1:2 ratio, which looks more square than 1:33. Given
that the camera captures the image on a 16/9 CCD, if
you want to film on 1:33 or more square formats, you
have to mask the viewfinder modifying its horizontal
and vertical marks to fit the sought format although
(pag. 25)
the camera is still shooting 16/9. However, if we film
on a 16/9 format but frame on 1:33 its necessary to
do something similar to a zoom during post-production
to change the image to 1:33, which causes a loss of
definition of around 20%. On a normal TV screen this
is hardly visible but this is not the case for a projection
on a 3x3’57 screen so we decided to use the whole
image without doing a zoom by placing the camera at
a right angle from the horizontal line of the frame.
By doing this and discarding the rest of the unnecessary
16/9 image we were able to compose a 1:2 image. This
ratio was established both in the viewfinder and on
the Sony HD 20 monitor.
Shooting at 30fps
Given that the image is projected into a space that
represents a certain era, the decorative elements had
to be integrated into the image, so we used guidelines
and masks on the monitor to have an accurate idea of
the tableau for the characters’ movements. We
have shot with the camera set at 30fps, which were then
converted to 601 due to the special characteristics
of the Mantis player. Although the F-900 records at
601, after the tests it became apparent that we achieved
a greater definition if we shot at 30fps and then convert
it to 601 than if we shot at 601 directly.
Wide angle lenses
The idea behind most of the projections was that they
appeared to be an extension of the real space created
in the museum. To ensure this succeeded, we had to choose
the appropriate lens, the height of the camera and its
degree of inclination with regards to the horizontal.
We intended to keep all the characters within the shot
at a 1:1 ratio at the edge of the frame, to create in
the audience the feeling that the characters were actually
there. We made tests with a digital Betacam camera with
a zoom at different focal lengths in a space that simulated
the museum. The first conclusion was that the wider
lenses gave better results. Given this, we made further
tests with the F-900 with three different lenses: the
5, 7 and 10 mm Digiprime by Zeiss at three different
camera heights (155, 160, 165cms) and tilts of up to
10º. We viewed the tests in the museum space with the
projector situated at the appropriate distance. From
these we found that the lens best suited for our purposes
was the 5mm at a height of 1,60 and with a 5º tilt (
this angle lowered the horizon giving it a greater continuity
with the museum’s floor ), and maintaining the
widest possible framing while at 3,30mts from the objective.
Given the fact that the 5mm is very wide and the camera
was also tilted, there were slight but noticeable deviations
of the vertical lines, which were corrected during post-production
to make all the vertical lines parallel without modifying
the framing. The quality of the 5mm Digiprime has been
excellent for its definition, crispness and colour reproduction,
and its exceptional depth and plane separation. We also
used the portable Zeiss COLIMADOR to properly adjust
the back focus. Our usual set of filters was the 85
series B&W promist.
The camera is placed therefore at 90º with a 5mm, at
a height of 1,60, with a 5º tilt and with the aperture
in most cases at 4 F-stops. One of the photographic
conditions was to have an aperture that allowed us to
have everything in focus because given the unusual position
of the camera the scenes devised played with the depth
in the space.
Menus, lighting
We configured the camera menus to obtain good details
in the blacks and as little loss of detail in the highlights
as possible. We did this with the ‘knee’,
the whiteclip and the slope at around 50, the gamma
table at 5 and the 709 ITU matrix, but depending on
the clip and the circumstances we modified the matrix,
the gamma and the black. To create the atmosphere of
the original light soft the era ( candles, oil-lamps,
petrol, summer or winter light ) we created specific
lighting designs, working with filters in the lighting
instruments, with correctors such as Calcolor, CTO and
CTB and slight modifications to the camera’s usermatrix,
to, for example, boost the warm tones. Ones we shot
the images we moved to the composition process: Chromas,
3D, lighting effects, etc.
Composition and colour grading
of The Baker
(Pag 26)
Hardware and Software
All the effects have been dealt with in an SGI Octane
2 station con 1/0 in HD, with 3 optic fibre arrays with
1 TB (1000 GB) and with a Jaleo HD software. We corrected
the colour ( with the image projected on the screen
by the projector that will be set up in the museum)
applied masks and corrected the geometry produced by
the camera lens.
To have total interaction with the projections its necessary
to use a video server that can be managed by a controller
software. After several tests, we decided to use the
Mantis server by Visual Circuits, controlled by a touch
screen and a CRESTON system that allows us to access
the clips in a random way and without jumps in the continuity.
Once the images have been processed they are transferred
to a PC where they are coded as a high definition MPEG-2.
The compression used is a Main Profile MPEG-2 at High
Level (MPEG-2 MP @ HL) at a 25Mb/sec bitrate ( above
the HD broadcast specifications ) with a LIgos plugin.
This process is quite slow because the image is so large
( 5 times larger than a PAL surface ) so we used a workstation
with 2 Intel Pentium 2 processors and a IDE Ultra DMA
4 disc array. The chosen projector is a NEC GT 1150.
With a resolution of 1024x768, 300 ANSI lumens and several
characteristics which help to configure the system,
such as the option of choosing the in-/out- aspect ratio.
This allows us to pan et scan in relation to our source
which was at 16/9, so the projection beam was filled
by our image.
After this process we observed a slight loss of resolution
as well as an increase in the noise of the image, loss
in detail in the whites and shadows due to the image
compression process as well as to the lower projector
resolution.
Technical info:
- Hdcam F900 Camera 30 psi 1/60
- Customized 1:2 screen ratio with the camera at a right
angle from the horizontal
- Digiprime 5mm Lens
- NEC GT 1150 Projector
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