[meteorite-list] Mystery

From: J. Fox <jfox_at_meteoritecentral.com>
Date: Thu Apr 22 10:07:05 2004
Message-ID: <3DBF6802.D9811A44_at_nevadalink.com>

Michael,

Your gif image is 141kb in size, and is 16 bit full color, and 453 x 432
pixels in size. It takes me approximately 28 seconds to download with
a 56k modem.

Your jpg image is 33kb in size, and is 16 bit full color, and 441 x 414
pixels in size. It takes me approximately 7 seconds to download with
a 56k modem.

I believe the reason for the smaller file size (hence faster download
time) for the jpg is that is is being processed using a file compression
algorithm (typical for a jpg), while the gif is a straight conversion
from your original image.

To convert the file to a gif, and keep a fair amount of color detail
in the image, I recommend the following procedure, although I haven't
used photoshop in about 5 years - so I may be a bit unclear in my
instructions (I use better software now.)

Take your raw file (tif, jpg, pict, etc.) and CONVERT it to an 8 bit
image, with optimized pallet, and reduced the colors to 64 (you may
be able to get away with 32 colors.) Next, save it as a gif. That's
all there is to it. You will now have a smaller file size, and it
will load quite fast.

I hope this is not too obscure. The key point is to reduce the amount
of information in the file. Reduce the sampling rate to 8 bit, and
reduce the number of colors to as few as you can get away with and still
have good definition and color rendition.

I hope others on the list will find this of use when preparing photos
for the web, either for items to sell, or to show their collections.

Best regards,

Jon Fox


Michael L Blood wrote:
>
> Hi all,
> I have a serious question:
> Well, this was the deal - I put up an image on my web site and
> decided to try a Photoshop feature that is SUPPOSED to make images
> much "smaller" in terms of data - and, therefore, download time. In
> Photoshop, it is under save this image as...."for the internet" and it
> makes it a "gif" instead of a JPG, and the "size" is listed at about
> 25% of a JPG, even though the dimensions are the same.
> Funny thing is, when Jim Hartman checked it out for me, he said
> the GIF took about 4 times as long than the JPG! (With cable, everything
> is "instant download," so, I can't tell)
> You all can check for yourself, if you like by going to my site,
> scrolling down to DHURMSALA. Try clicking on the JPG and then on
> the gif and see how long each one takes to come up.
> My question is: IF the gif is supposed to be using only 1/4 the
> memory of the JPG of the same image of the same dimensions, then
> WHY is it taking LONGER to download than the JPG???
> Anybody know?
> Thanks, Michael
>
> http://www.michaelbloodmeteorites.com/
>
> on 10/29/02 3:23 PM, Michael L Blood at mlblood_at_cox.net wrote:
>
> > Hi David & all,
> > I need some very brief assistance - from someone who does
> > NOT have cable or other ultra fast download capability to check
> > something for me.
> > Will anyone who is "up" on the list right now without such
> > high speed internet access please email me off line?
> > THANKS, Michael PS: Don't take any wooden meteorites.
Received on Wed 30 Oct 2002 12:02:58 AM PST