ANSWER TO REVIEW QUESTION 3
It is standard drafting practice that the front view show the object's most characteristic features. (para 1-4,a(4))
ANSWER TO REVIEW QUESTION 4
An auxiliary view is made by projecting a slanted face onto an additional drawing plane placed parallel to it. (para
1-5,a)
Section Ill. Types of Prints
comparable cost but the wet developing process
1-7.
CLASSES OF DRAWINGS
causes some distortion and marking the prints is
Drawings are normally classified as original
difficult.
drawings, intermediate or reproducibles, or prints.
The original drawing is the one produced by the
(2) Brownprints.
The brownprint
draftsman. An intermediate is a copy of the original
process (often called Van Dyke) is similar to the
which is used to make prints. An intermediate is
blueprint process except that the paper is transparent
used to avoid the risk of damaging the original or
and exposed areas turn brown when developed. This
because the original is not suitable for the type of
yields transparent lines on a brown background.
reproduction process used for the making of prints.
Brownprints are frequently used as intermediates
Prints may also be made directly from the original
producing a print which has blue lines on a white
without using an intermediate drawing. A print is a
background and called a white-print.
working copy used on the job.
b. Positive Contact Processes.
1-8.
PRODUCTION PROCESSES
(1) Ozalid prints. The ozalid process is a
There are many processes used to make prints
contact process like blueprinting but the unexposed
from originals or intermediates. They can be
areas of the sensitized paper turn blue when
classified as either negative or positive contact
developed in ammonia vapor, producing blue lines on
processes or optical processes. Contact processes
a white background. Ozalid prints are also called
require a transparent or translucent original. Optical
blueline prints. Papers are also available which yield
copies can be made from opaque originals. Contact
black lines (called blackline prints).
The
processes are normally used in construction work.
development in this process is dry, causing less
Optical copies are usually more expensive and
distortion than the blueprint process, but the contrast
introduce more distortion.
is not usually as good.
Machines are available which
Note:
a. Negative Contact Processes.
produce ozalid-process prints but which project and
(1) Blueprints. A blueprint is made
reduce the image optically instead of contact-
by placing a tracing (transparent or translucent
printing. Prints produced by this process will usually
original) in contact with a sensitized paper and
be marked "Reduced Size Print -Do Not Scale."
exposing the paper through the tracing. When the
(2) Brownline prints. Brownline prints
paper is developed, the unexposed portions where the
have the same function in the ozalid process as the
light is blocked by lines on the original remain white,
brownprints do in the blueprint process. They
while the exposed portions turn dark blue. This
produce brown lines on a transparent background and
produces a print with white lines on a blue
are often used as an intermediate for making blueline
background. Blueprints, in general, have better
prints. Brownline prints are often called sepia
contrast than other commonly used processes of
intermediates.
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