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© 2014 CPRR.org. Use of this Web site constitutes acceptance of the User Agreement which permits personal use web viewing only; no copying; arbitration; no warranty.
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Stereoscope (H. Ernemann). Courtesy
Bogdan
Stroescu.
Freeviewing (seeing the image in 3D without a stereoscope) with a
large monitor.
Once you have learned to freeview, it's easy to freeview a 2x stereoview
(as shown in the Exhibit and Photo-Gallery on our website) on a large monitor.
The trick is to view from about 4 feet away and to use a distance prescription,
not reading glasses. (Easy to focus when looking above the line of
bifocals, difficult when looking through the lower reading portion.)
For an explanation
of how to freeview, click here.
How
to See Stereo (Relaxed viewing), click here.
If you are unable to freeview, an unmagnified Folding
prism stereoscope suitable for viewing stereoviews displayed on a computer
has been invented
by Monte Jerome Ramstad.
Compatibility Testing.
We have tested this website with Netscape Communicator/Mozilla,
Microsoft Internet Explorer, and Safari and are not aware of any incompatibilities.
Website
Garage reports Excellent Broswer Compatibility and HTML code check.
Please let us know if you experience any problems.
Browser Bug — does not display wide images properly
One popular browser does not correctly display wide high resolution
maps, diagrams, and panoramic images, etc., cutting off the right side of the
image
which
is not displayed;
Another browser gets the shape of large images wrong, or pretends that the picture
is missing. There
is
nothing
at all wrong with the pictures.
If the spectacular Alfred A. Hart Map of "THE
BURLINGTON ROUTE" is missing the word "ROUTE" in large green letters
on the top right, or if large images appear squeezed in one direction, you have
one
of
these
defective
browsers,
and
should complain to the software company about the problem and choose another
web
brower that works correctly to view such wide images.
"I had a life once ... now I have a computer and a modem." —Rafey
Browser Bug — clicking a link stops download
Many of the pages at the CPRR Museum are designed so that you can enjoy viewing
the
top
of
the
page
while
the rest of the page (including large pictures) downloads so that the rest of
the page will
be
ready in time as you scroll down the page. However, some browsers stop downloading
a page and its images whenever you click on a link. That makes complete sense
if the link is to another page that will be displayed in the same window, but
is incorrect behavior if the link is to another place on the same page, or to
another page that will display in a separate, new window. Consequently, if your
browser has this problem, you may need to take
care to wait until each page finishes downloading before clicking on a link,
if
you
want
to
avoid interrupting that page's downloading. If you click on a link prematurely
and
find
that as a result,
pictures
are
missing
or only partly displayed, or the bottom of the page is missing, hit the reload
button to fix the problem.
(If images still fail to fully load following a refresh, it may be necessary
to clear your browser's cache, and/or quit and restart the browser, before
trying
to
load
the
page
again.)
Changing Text Size.
![Large Type Edition. [Courtesy ©ASNR.org]](images/I_ACCEPT_the_User_Agreement/logos/Large-Type_ASNR.gif "In most browsers you can increase the font size with a trip to the \"View\" menu. Look for something called \"Text Zoom,\" \"Text Size,\" \"Increase Font,\" \"Make Text Bigger\" or similar. [Courtesy ©ASNR.org]"){kind=small}
TIP FOR BETTER WEB BROWSING:
Large Type Edition —
To reduce eye
strain when reading articles online, increase the
font size for your browser.
In most browsers you can accomplish this with a trip to the "View" menu.
Look
for something called "Text Zoom," "Text Size," "Increase Font," "Make Text Bigger" or
similar. Courtesy ASNR.
More web
browser tips.
Universal Access for the visually impaired can also be assisted by software that enlarges the screen image. We also provide catalogs with text captions describing the transcontinental railroad images.
"I don't have any meetings today. I'll just fool around with my computer's settings until it doesn't work." —Dilbert cartoon
Download Speed.
The CPRR.org website was designed to show the wonderful Central Pacific
Railroad images with reasonably fast load times while not sacrificing image
quality. Page load times from the Internet have been measured at
times of low congestion, confirming that the homepage loaded and displayed
in less than 20 seconds, and pages with large individual images generally
loaded and displayed in under 5 seconds using a cable modem or DSL.
This testing was done using Netscape Communicator 4.76 and Internet Explorer
5.0 running on a 5 year old slow Power Macintosh 7200/75 using Mac OS 8.6
and 9.0.4 with a SURFboard external cable modem also also with an ADSL
gateway attached to the computer by ethernet connection. (Since this testing
was done several years ago, broadband speeds have significantly increased.) Surprisingly,
these measured Internet page load times from a server 1000 miles away were
found not to be significantly different from load times directly from our
hard drive using the local disk copy of the website on our computer.
We have also tested with dial-up connections and regret if Internet congestion
or a dial-up modem connection make your viewing unpleasantly slow.
Hopefully, an inexpensive high speed internet connection ($29.95-$49.95/month)
will also be available to you in
the near future – you should definitely take advantage, if available! A
March,
2004
Nielsen/NetRatings
study
found
that
42% of home users and 77% of business users had high speed broadband connections.
If
browsers
were
properly
designed
to download images that are visible in the window ahead of off-screen images
that will not
be immediately visible, images would appear on screen dramatically faster.
This website is hosted by ValueWeb.
If you have a cable or DSL high speed connection that is sluggish, you
possibly need to properly tune your Windows
or Macintosh
system and may see a dramatic speedup, since the default networking parameters
may not be correctly set for high speed Internet connections.
System requirements for eBook viewing.
This website contains a number of electronic books in pdf ("portable document
format") which require pdf viewing software to
view. The entire book is contained in one very large file (tens of megabytes
in size), so you'll need a high speed internet connection, and a fast computer
with lots of memory or viewing may be very slow. (The big advantage
of
this
format is
that
you can search the page images using the "find" command.)
Dual 19" Monitor viewing.
The Photo-Gallery and Exhibit are best viewed with the index page on
the left monitor and the enlarged stereoviews in a separate window on the
right monitor (each monitor 1024 x 768 pixels). Clicking on a small
image on the index page automatically opens a second window with the magnified
image [close the extra windows when done]. Having two large monitors
is a delight for Internet browsing and has recently become quite affordable.
Having two 19" monitors is highly recommended, second only to a high speed
connection, such as by cable modem or telephone DSL.
"A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools." —Douglas Adams
Color Scheme.
The black text on a red or yellow background appearance used on the
CPRR.org website was chosen to approximate the most common colors used
by the 19th century photographers (Watkins and Hart, respectively) when
mounting CPRR stereographs. Sometimes a page will provide its owns
colors and background which you can override by setting your own preferred
browser colors if you don't like our choices or if you find pages difficult
to read, for example, due to color blindness. In Netscape Communicator
set the Appearance/Color preferences to the text and background colors
that you can see best and check the box to "always use my colors, overriding
page." In Internet Explorer set the Web Browser/Web Content preferences
to the Page & Links colors that you want for the text and background
and uncheck the Page Content option to "allow page to specify colors."
(Various versions of browsers may have these preferences set slightly differently,
so look around to find them if color preferences are not edited exactly
as described here.)
Also, you can easily change the red background of the Home
page or the blue background
of the Exhibits page to
suit
your taste – see the background color choices near the top of the
page, and click on your preference.
Grayscale for Monitor Calibration.
The appearance
of the images displayed on the CPRR Museum website "can be greatly affected
by
the brightness
and contrast settings on your monitor. If the images appear too
dark please make sure that you can distinguish each percentage bar. For
instance, the 40% and 50% bars are clearly distinguishable and so should the
90% and
100% bars. If
they appear to blend together then adjusting your brightness and contrast settings
should make them distinguishable."
You can also verify the color
and contrast settings.
Grayscale Courtesy of an Anonymous Donor; reproduced by permission.
"On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question." —Charles Babbage, "Father of Computing"
Optical Character Recognition.
Many of the readings were automatically
converted from scanned or digitally photographed19th century original documents
by means of Optical Character Recognition (OCR) software. This allows
us to have many more 19th century documents on this website than we would have
room to
include without doing this conversion. Whenever we have found images
of the original text pages available on-line, as is now often the case
with 19th century magazine articles,
we have also included links with the article, to allow you to view the
original. While the accuracy of OCR has greatly improved, particularly
when the text is very distinct, it still has significant limitations, especially
when the original is imperfect, and when dealing with formatted text, difficult
typefaces, tables and superscripts. As a result we must give you
a very strong WARNING: DO NOT RELY ON OCR CONVERTED TEXT. These
OCR converted documents are very useful for casual reading and searching with
your browser's find command, or our website search capability, but
you must examine the original documents if accuracy matters.
Never rely upon a date, number, formula, or other detailed information
without first checking its accuracy, as the OCR software often inserts
errors which are not the sort of mistake a human would make or easily recognize.
We have corrected many such errors, but undoubtedly numerous others remain,
and our limited resources prevent us from fully verifying all the text.
We have also chosen to make available converted documents before the formatting
and limited proofreading is completed. If you identify any errors,
let us know. If you would like to volunteer to proofread one or more
documents and let us know about errors that need to be corrected, we would
be most appreciative — if you don't have access to the original document,
contact CPRR.org to see if we are able to fax you a copy for proofreading. In
some cases, we display page images on html webpages and hide the imperfect
OCR text in a tiny font at the bottom
of
the
webpage, with the text almost the same color as the page background,
to
allow
search
engines
to
index the page. Sometimes we include the entire text of an article on a webpage
above an image of the first of several page images, with subsequent page images
on following webpages.
In
other
cases,
a
complete
book
or
document
may
be
presented
online as all page images in a pdf format file with OCR text
under the page images,
so
that
you can see the original, but the text can be searched using your pdf viewer's
find command, and can be indexed by search engines. The various presentation
formats
have
been used to accomodate varying degrees of quality of the original copy, success
in
OCR,
whether
the
resources have been available at the time to do extensive proofreading and manual
corrections,
and
as
the
scanner
and OCR software
have changed or improved over time.
[Some common OCR errors: (l —> d ; lie —>he ; ),on —>
you ; Dot —> not ; tip —> up ; 1 —> I ; oil —> on ; tile —> the ; bad —>
had ; yon —> you .]
How to avoid illegible black lettering on a red
background (Watkins and Houseworth views).
To avoid severe smearing of the black lettering on red cards when saving
jpeg images, it is essential to enable the optional (4:4:4) Sub Format.
(This option is available in the Photo-Paint component of Corel Draw 8:
144 dpi 2x magnification, JPEG Enhancement- 14% compression, 0% smoothing,
Optimized Encoding with Optional (4:4:4) Sub Format used for red cards.)
This is not necessary for Hart's yellow cards, as Photoshop's default medium
jpeg images do not show smeared black lettering on a yellow background,
as they do with black lettering on a red background (Adobe Photoshop LE
3.0: 144 dpi 2x magnification, JPEG medium used for yellow and other
color cards, except red). Alternatively, 8-bit gif images of red
cards are excellent, lacking this smearing problem, but are about 80% larger
(less efficiently compressed) than the (4:4:4) Sub Format jpeg images.
How can unacceptably discolored or unevenly colored sepia images be corrected?
"There are 10 kinds of people in the world, those who understand binary, and those who don't." —anonymous
How to avoid reflections and slightly off color interference patterns
when scanning images.
Take the stereographs out of their Mylar plastic sleeves when scanning
to avoid light reflections off slight curves in the shiny Mylar and also
to avoid "Newton's rings," the slightly colored interference fringes resulting
from the very close distance separating the plastic sleeve from the glass
surface the stereograph is resting upon when in the scanner. (But
make sure that the scanner's glass is clean before allowing the photograph
to come in contact and use photo gloves when handling the stereographs.)
How to avoid moiré patterns when scanning engravings.
Scan at the highest available resolution in full color (600 dpi).
Shannon's sampling theorem requires the scan to be at twice the highest
spatial frequency in the engraving to avoid aliasing. Then resample
the image to the desired reduced screen resolution (72 dpi), which eliminates
the high frequencies by averaging pixels, so that the annoying wavy patterns
are avoided.
"There's no place like 127.0.0.1!!!" — robpoe
How to scan large maps
or blueprints using a standard small format scanner.
The Maps
page includes
scans of some large format maps which we were able to include without having
an expensive
large
format
scanner available. The simple trick is to use a blueprint duplication photocopier
(which is a common service at specialized copy centers) to make a reduced
size photocopy.
We found that two size reductions resulted in an 8 1/2" x 11" high
resolution copy that could be scanned using a readily available page size
scanner. Two examples of using this method are the California and Nevada survey
maps.
The quality of photocopies is considerably less than that of original continous
tone or color maps, so we would not recommend this method when original maps
are available, but
when only large format blueprints or photocopies are available or when the
original is line art, there is little loss of image quality from the additional
size reduction copying
steps as the large format photocopiers used by architects and engineers are
of extremely high quality. Although time consuming, alternatively, it is
also feasible to scan a large format original in sections which are then
carefully
aligned and put
back together using Photoshop. An example is the Sierra
Summit contour map which was reassembled from two scans.
Is Internet display of high resolution stereograph images currently
possible?
Not with the entire image being visible at one time. Stereoviews
consist of a pair of images, each about 3 1/2" in size. The 19th
century views shown on this website are of small albumen prints which themselves
are not capable of high resolution. When we speak of "high resolution"
what we actually mean is that the digital image does not further degrade
the resolution. To do this 600 dots per inch (dpi) scans of the original
stereoview are marginal, and 1200-2400 dpi would actually be required to
capture the full available resolution of the original stereoview.
Due to equipment limitations we have reluctantly compromised on 600 dpi
which may be acceptable because much of the detail being lost is the appearance
of the emulsion itself rather than useful photographic image information.
(Albumen prints have a fine pattern of cracks in the emulsion which cannot
be seen on 600 dpi scans but could result in aliasing artifacts.)
With improved scanners, faster computers with more memory, larger disk
drives and recordable media, and improved image compression methods we
hope to find it practical to scan stereoviews at 1,200 dpi in the near
future. However it is not possible to display even a 2,100
x 4,200 pixel, 600 dpi stereograph scan in its entirely on the 72-95
dpi CRT monitors or flat pannel displays currently used for computers now
available for Internet browsing. To have a 600 dpi image fit on the
screen, the display resolution would need to be increased by a factor of
4 to about 300 dpi (which is true medium resolution such as seen with low
cost consumer printers; quality printers use a minimum 1,200 dpi on the
paper or much higher for commercial printing) and because images are two
dimensional, a broadband connection, computer, and graphic display system
16 times faster than currently available would be required to keep download
and display times similar to those currently experienced. These will
probably not start to be in common use until at least 2005-2010 or later.
An improvement of 256 times would be needed to display high resolution
1,200 dpi stereoview scans, which will not be possible anytime soon.
How does the "wobble stereo" 3D animation
on the homepage work?
The example of animation on the
homepage and the stereo exhibit, inspired by Miklos
Legrady's work, uses a simple javascript to swap a correct stereoview
with a Photoshop created pseudoscopic version of the same view under the
full control of the user. (In a pseudoscopic view, the left and right
stereo images have been interchanged.) Legrady uses a continuously
animated single image (half a stereoview), but we thought it would be interesting
to show the animation with the entire stereoview. Changing an image
when you point to it is a standard browser effect ("javascript
rollover"). Thus, moving the cursor back and forth across the
picture's edge causes the animation whenever and as fast as the viewer
wants, and avoids visual discomfort. This simple trick which gives
the user control of the animation might have wide appeal, as it is unobtrusive
when not being deliberately invoked.
To achieve the appearance of rotation, the two images are aligned so the nearest
object is in the same place.
Copy Protection.
If you would like to use images from the CPRR Museum on your website, see
this FAQ. This website depends for its existence and continued availablity
on the good will and support of donors willing to allow their valuable images
to be displayed on-line. We hope that allowing personal educational viewing
at the CPRR Museum website at no charge, while charging a use
fee for copying is a good compromise, but when images are taken without
permission, it puts our entire project in jeopardy. Pages on this website
are designed to help prevent unauthorised downloading of images and breach of
both copyright and the User Agreement. We have tried to do this in unobtrusive
ways that don't impair the quality of your experience at the CPRR Museum.
We regret that copy protection has become necessary, but it was put in place
only after repeated pirating of content from the CPRR Museum website.
For example, an institution took our entire website, removed the copyright notice
from our homepage and republished a seriously obsolete version of the CPRR Museum
on their webserver with the files jumbled so badly that most of the links were
broken, and then they distributed the broken pirated copy of our work to other
institutions on compact disk, thereby damaging our reputation. In another
case, a foundation hosted a website that copied about 50 of our most spectacular
images without permission. In yet another instance, a donated rare photograph
that was a treasured family heirloom was copied and placed on another website
without credit, while falsely claiming that it was theirs. (Their webmaster
became irate when at the request of our very upset donor we politely asked them
to please link to our page instead.) ... While it may be possible
to circumvent technical copy protection mechanisms, please don't do this both
because ripping off the pictures isn't a nice way to repay our donors for their
generosity in supporting this project, and also because doing so was recently
made a serious Federal crime under the Digital Millenium Copyright Act.
Instead, please ask for permission.
We would be delighted to hear your design
suggestions — How can we improve this website?
— we've been wrestling with a number of technical issues (as noted
above and on our FAQ's page):
We've tried to keep the design of this website simple — without frames or
Java programming — while maximizing the area available for images, given the
limited
resolution of CRT's. Here are some issues that we're aware of but
haven't found entirely satisfactory solutions for:
