Welcome to Rich Franzen's

PNG Gallery

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    ( Wrong PNG?  Try Papua New Guinea Pictures )
    ( Right PNG?  More PNG images via libpng.org )

    Square Snakes

    Snake with 4096 grey scales
    21 kbytes  (320x320 by 12 bits)
    The above image contains 4096 shades of grey.

    Snake with 65536 grey scales

    317 kbytes  (1024x1024 by 16 bits)
    You will see an image with lots of shades of grey by clicking above.
    The raw pixels for both "snakes" were generated with
    a program which I wrote several years ago.

    Bookoo Colors and Greys

    For an interesting complement to the above Image of 65536 Greys, play with my interactive Page of 60,480 Colors
    color wheel

    66 kbytes (Adam7)
    (632x546 by 24 bits)

    For you square-snake lovers, click on over to the original home of pseudoGrey.  See how to squeeze 1786 levels of grey from an image which only provides 256.
    1x1 pseudoGrey Snake

    1132 bytes
    (64x64 by 24 bits)
    1786 levels of grey

    Round Snakes

    I have not forgotten the round snake lovers, but caution! The following image uses an "anomalous motion illusion", which might make sensitive observers dizzy or sick. Should you feel dizzy, you had better scroll past this image quickly.
    Rotating Snakes
    rotsnake_cropped.png, 115 kbytes, 599x477 pixels, 8-bit image
    from Rotating Snakes, Copyright A.Kitaoka 2003
    No, it's not really moving.  At least I don't think it's moving...

    Clicking the image above brings you to the English version of Akiyoshi's illusion pages.  Dr. Akiyoshi Kitaoka is an Associate Professor of psychology at the College of Letters, Ritsumeikan University, Kyoto, Japan. Unfortunately his site uses mostly GIF images along with a few JPEG images. Even so, they are amazing!

    The optical illusion of motion reminds me of the quest to build a perpetual motion "overbalanced wheel".  In the case of the rotating snakes, though, your eye and mind make it work.

    Dr. Donald Simanek is Professor of Physics at Lock Haven University of Pennsylvania. His Museum of Unworkable Devices is another great site (which unfortunately uses GIF images).
    ... <sigh>  Maybe it's a doctor thing ...

    overbalanced wheel
    134x124 by 64 greys

    Full Color Break!

    big file o' peppers
     (aka 'hell.png')
    659 kbytes  (512x512 by 24+8 bits)
    by Lee Crocker
    surf's up

    354 kbytes  (800x538 by 8 bits)

    Check out the PNG'd  (pang?)
    Kodak PhotoCD PCD0992
    Use above link to get to all 24 thumbnails.
    The images are large, 24 bits, and lossless.
    rustic dream
     686 kbytes

    Monitoring the Monitor

    grey bars and ramps

    11 kbytes  (1024x1024 by 11 bits)
    This monitor test image was built years ago
    by Chris Eizember of DuPont on their NDT Scan IV system.

    The two files below are the same SMPTE RP-133 image;
    the one on the left was saved using PNG's Adam7 interlacing format.
    4096x4096 by 12 bits/pixel (2 bytes/pixel)
    huge PNG-interlaced SMPTE RP-133 pattern

    156 kbytes
    huge PNG SMPTE RP-133 pattern

    104 kbytes

    Actual 16-bit Scan

    resolution chart, scanned at 42 microns

    2.5 Mbytes  (1280x1280 by 16 bits)
    Source image was a very old lab film.  Scratches are real!

    Graphics at Work

    business-graphics example
    , Business Graphics Example
    14 kbytes  (616x472 by 5 bits)
    equivalent GIF is 26 kbytes  —  75% quality JPEG is 38 kbytes
    Check out this clean, business-oriented slide-show.
    counter     Valid HTML 4.01!
    Accesses since 1998-08-15
    Last updated 2013-06-15
    Enjoy!  Rich

    RWF Home

    fish bowl, multiple levels of tranparancy
    teaser: Fishbowl Globe by Diana Todd