RE: Calculating Scan Size

Sandy, These were files that were worked on as smaller components. In
sending out a file for film recorders, the required file size exceeded the
cd limits, but each component was only about 100mb. Working in grayscale my
files were each intended to be output to 4x5 film negatives. Making a 4 up
of 4x5s to an 8x10 negative allowed each file to be reasonable in size. It
was only after integrating the parts and preparing the file for the labs out
put requirements that I ran into the problem. They work in RGB.

I have yet to work on files that are 700 or 800 mb that need manipulation.
RAM, RAM and more RAM would be the answer. Having upgraded to Photoshop CS
( the whole CS package really) I will no doubt need all I can get. Much of
my computer work is going directly to an Epson 7000 with Cone inks and Image
Print software. I only need an output size of 360dpi to get very nice
results so even my 20x24 images are only 150mb or so.

Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://e.neilsen.home.att.net
http://ericneilsenphotography.com
 

> -----Original Message-----
> From: Sandy King [mailto:sanking@clemson.edu]
> Sent: Saturday, February 21, 2004 9:59 AM
> To: alt-photo-process-l@sask.usask.ca
> Subject: RE: Calculating Scan Size
>
> Eric,
>
> I am just curious how you are able to work on files that are too
> large to fit on a CD? It takes my Mac G4 forever to make changes in
> Photoshop on anything larger than 700mb-800mb.
>
> Sandy
>
>
>
>
> >Sandy, Perhaps it is time for a DVD burner and move up the scale. ; )
> >I had a couple of frustrations with files just a bit too bit for a cd.
> >
> >
> >Eric Neilsen Photography
> >4101 Commerce Street
> >Suite 9
> >Dallas, TX 75226
> >http://e.neilsen.home.att.net
> >http://ericneilsenphotography.com
> >
> >
> >> -----Original Message-----
> >> From: Sandy King [mailto:sanking@clemson.edu]
> >> Sent: Friday, February 20, 2004 2:41 PM
> >> To: alt-photo-process-l@sask.usask.ca
> >> Subject: Re: Calculating Scan Size
> >>
> >> My purpose in asking the question has nothing to do with arguing
> >> point. I am making some scans of large 5X7 negatives and want to keep
> >> total file size below 700mb so I can save the raw file to a CD.
> >> Unfortunately the scanning software that I am using does not tell me
> >> the final file size after I indicate resolution and target size, as
> >> some software does.
> >>
> >> Sandy
> >>
> >>
> >>
> >> >Good point. I always scan into an uncompressed 16 bit TIFF so I
> didn't
> >> even
> >> >think about getting into compression. Mike's right because there
> really
> >> is
> >> >no easy way to calculate size on disk.
> >> >
> >> >Those calculations are handy when you get in a digital vs. analog
> >> argument
> >> >and someone brings up megapixels as their only arguing point. My
> >> response?
> >> >Well if you're only counting megapixels then I've got way more on a
> 645
> >> >negative than you do.
> >> >
> >> >:p
> >> >
> >> >-Jon
> >> >----- Original Message -----
> >> >From: "Mike Finley" <ekng532@f2s.com>
> >> >To: <alt-photo-process-l@skyway.usask.ca>
> >> >Sent: Friday, February 20, 2004 2:26 PM
> >> >Subject: Re: Calculating Scan Size
> >> >
> >> >
> >> >> On Fri, 20 Feb 2004 14:11:43 -0500, Jon Danforth
> <jdanforth@sc.rr.com>
> >> >> wrote:
> >> >>
> >> >> >Sandy,
> >> >> >
> >> >> >Try using the scan calculator at scantips.com. I use this all
> the
> >> time.
> >> >> >
> >> >> >http://www.scantips.com/calc.html
> >> >> >
> >> >> >For instance, scanning a 645 negative at 2400dpi yields these
> >> results:
> >> >> >
> >> >> >Input
> >> >> >(2.205 inches x 2400 dpi) x (1.693 inches x 2400 dpi) = 5291 x
> 4063
> >> >pixels
> >> >> >Output
> >> >> >(10.419 inches x 508 dpi) x (8.000 inches x 508 dpi) = 5291 x
> 4063
> >> pixels
> >> >> >
> >> >> >This also gives you the equation for calculating it on your own
> later
> >> on.
> >> >> >To get the size in MB, you'll have to then multiply each value by
> the
> >> >number
> >> >> >of bits per channel (8 or 16) by the number of channels. Then
> you
> >> divide
> >> >> >multiply the number of bits by 8 to get the number of bytes and
> then
> >> >divide
> >> >> >that number by 1024 to get the number of megabytes.
> >> >> >
> >> >> >So if you have a grayscale image, that's 5291 * 8 = 42328 + 4063
> * 8
> >> =
> >> >32504
> >> >> >= 74832 bytes / 1024 = 73.08 MB.
> >> >> >
> >> >> >RGB color is just three times that (roughly). Keep in mind that
> >> these
> >> >> >calculations are based on scanning at 2400dpi.
> >> >> >
> >> >> >There's probably a more simple way of doing it but I'm a bit
> rushed
> >> right
> >> >> >now. The light outside is AWESOME.
> >> >> >
> >> >> >-Jon
> >> >> >
> >> >>
> >> >> This gives the megabytes of image data in the file, but doesn't
> >> >> necessarily equate to the file size on the disk, if that was what
> >> >> Sandy was asking about.
> >> >> Some formats compress heavily, and throw away data in the process,
> eg
> >> >> JPEG
> >> >> Some formats compress less heavily and can restore exactly the
> same
> >> >> data when opening the file.
> >> >> Some formats do not compress at all.
> >> >> Tiff files can be any of the above, depending on options chosen
> >> >>
> >> >> In addition to the image data there will be a small amount of
> >> >> additional data needed to identify the contents to software that
> is
> >> >> using it.
> >> >>
> >> >> So if you are talking about file sizes on disk, then there is no
> >> >> direct correlation to resolution and image size.
> >> >>
> >> >> mike
> >> >>
> >> >>
> >> >> mike
> > > >> Mike Finley, http://www.efikim.co.uk
Received on Sat Feb 21 11:34:34 2004