Re: [OT] ideal file size of a jpeg or gif image

[James Brook <ajmbrook@ozemail.com.au>]

Chris Gordon wrote:
> 
> James, I have had a couple of my 640X480 photos, only in JPG format
> (around the 100kb mark) used on a number of internal reports in
> Victoria.  I have seen the covers with the photo printed in nice colour
> and about 1/3 of A4 size and they come out very nicely.
> 
> The first photo was pinched and they told me about that later.  (better
> not say who they are).
> 
> Second photo was used with prior permission by the government on a
> report.
> 

I was referring to full A4 size so if you print an image smaller, you
won't need as much data. However, 640x480 will not produce full photo
quality as the data just isn't there to begin with. While it may produce
a nice looking image, it will either be a little bit blurred or blocky,
depending on the program used to print it.

For a 1 to 1 transformation from the screen to paper output, a 600dpi
image at 910x600 from my site would need to be stretched to 2363x1557 to
print at 10cm wide. If you use photoshop to stretch it, you will end up
with a reasonable image, but it won't have the very sharp detail that
would be there if the image was originally 2363x1557. Again, if you want
to print it at 600dpi on a full A4 sheet, you would be looking at
6614x4360. Clearly, if you start off with a higher resolution, you will
have a better output than if you start off with a lower resolution. You
probably wouldn't be able to get anything more than 1/3 A4 size with
640x480, even then it is not true photo quality. The images on my site
will not provide true photo quality either.

-- 
- James Brook -

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