 In
the case of Hubble Heritage images, larger files
do not necessarily mean more detail. Hubble's digital
cameras produce images of fixed size (a maximum
dimension of 1600 pixels as in the above image)
that are not large by usual graphics standards.
Therefore, we recommend copying and printing the
"big" JPEG images available from the Heritage site.
These are nearly the quality of the originals but
will download much faster than a full-size, uncompressed
image (see formats below). Although any image can
be reproduced at larger reproduction sizes (for
example poster size), individual pixels may be visible
even in our uncompressed tiff images.An attempt
to increase the resolution by increasing the number
of pixels beyond the data's original dimensions
will degrade the image. So we match the dimensions
of the image to the dimensions of the data rather
than convert it to sizes standard for monitor wallpaper
or posters.
Note that if you are running color intensive applications,
your computer will not use a full color table to
display the image. Monitor wallpaper, and even the
borders of windows steal colors from the available
palette. Additionally, if your monitor is 8-bit
your image might appear dotted or hatched. Often
you can set your applications to compensate for
these effects.
Here's an example for ensuring the UNIX XV application
displays a reasonable texture and color rendition
even on an 8-bit monitor. After loading the tiff
or jpeg file into XV, open the XV control panel
by clicking on the image with the right mouse button.
In the "24/8 Bit" menu select the algorithm "Slow
24->8" and then select "8-bit mode". Then in the
"Display" menu select "Perfect Colors" or "Use Own
Colormap". A line near the bottom of the XV control
panel will state whether or not you now are using
all 256 available colors.
Note that you may wish to dim the overhead lights
and/or adjust the intensity and contrast settings
of your monitor. As an aside, your browser permits
you to select your own colors for hyperlinks and
select your font size for the text. In the browser's
"Edit" menu, explore the "Preferences" control panel
to customize your display.
Format and File Size
The information in the smaller format release
images, which are roughly 400x500 pixels square,
has been compressed so that they download more quickly.
Their file size is usually under 120 kilobytes.
The big size images, 800x1000 pixels, range from
50 - 400 kilobytes. To check the file size of a
specific image, move your cursor on top of the small
version. A window will appear with the number of
kilobytes of both that image and the big image it
links to.
The release images are presented in JPEG format
which includes image file compression. This may
slightly degrade the image from the original. Note
that editing a JPEG and saving it as another JPEG
will degrade the image further.
You can use your browser functions to download
these files to your disk. For example, in Netscape,
go to the image you want, click the RIGHT mouse
key and select "Save Image As...". Your browser
should open a window asking for a directory on your
computer and what you would like to name the file.
Similarly, in Internet Explorer, click the RIGHT
mouse button on the image and select "Save Image
As...". Also note that the image may already be
stored on your disk in the browser cache area, in
which case you simply have to move it to another
directory in order to save it.
Convert downloaded images to monitor wallpaper
using a standard graphics package such as GIMP or
Adobe Photoshop. Alternatively, your computer software
may provide specific applications for making desktop
backgrounds. Note that replicating pixels in order
to increase the resolution of the Heritage images
to fill your monitor area may make them blurry.
(See notes about the images natural resolution above.)
This is why the Hubble Heritage Project does not
provide wallpaper or screensavers. Check our copyright
if you wish to use any image for a purpose other
than for your own personal use.
Hubble Heritage images can be reproduced without
requests for permission if the credit line is "NASA, ESA,
and The Hubble Heritage Team (STScI/AURA)." (Hubble
Heritage image credits are listed in each image's
description and links to descriptions are on the
gallery page.) Please remember to properly credit or acknowledge the credit line in the reproduction of the image.
However, if a credit line or a credit note beside
the image includes other institutions and individuals,
then these individuals must also be contacted for permission. More information on Copyright issues at STScI is available.
Posters and Photographs
Posters and prints are produced by many outside
vendors. Doing a net search on "Hubble Poster"
will point you to a number of these sources. Among
them, the Astronomical
Society of the Pacific and Sky
Publishing, have been known to sell posters
and prints of Hubble images.
For educators: There are some resources specifically
designed for education available here at the Education
Group at Space Telescope Science Institute and
NASA provides educational resources through NASA
CORE.
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