Best scan size for 8x10 prints?

ColdCanuck wrote:

"Raphael Bustin" wrote in message
...
The only exception (in my experience) was the
Motorola 56K DSP, which has 24/48/56 bit accumulators
and internal data paths.


Hmmm...this is going back aways (and *really* OT), but didn't Data General
do something funky in their "Eagle" line?

...talk about being a geek, eh?

CC

From a programmer's point of view, the Eagle (officially MV8000) was an
ordinary 32 bit machine. Technically it had some tricks. For example, it
also supported the full 16 bit instruction set of the Eclipse, which
itself had the 16 bit Nova instruction set as a subset. It was possible,
because the Nova set had 2^11 instructions that either did nothing or
always skipped the next instruction. The Eclipse redefined the first
group, the Eagle the second.

-- Lassi

P.S. Tracy Kidders's book "The Soul of a New Machine" is still one of my
favourites...

Raphael Bustin wrote:

On Fri, 20 Feb 2004 13:23:32 GMT, "Reciprocity Failure"
wrote:

I understand (could be wrong, I'm not an expert) that Photoshop will show 16
bits in the mode window whenever the bits are more than 8 so the fact that
16 is checked doesn't necessarily mean it's really 16 bits, only that it's
something more than 8.

Yep, anything above 8 bits requires a 16-bit field,
since tradtional computer architectures support
data sizes of either 8, 16, 32, or 64 bits. (Floating
point is another story.)

Traditional computer architectures were usually multiples of 6 bits,
most commonly 12 or 36, sometimes 24, or even 60 (CDC). 6 bits was good
for most engineering purposes, because it was enough to represent the
full alphabet, and 12 bits was the industry standard for process
control.

IBM was the first to use 8 bits in a major way. In business applications
they needed both upper and lower case alphabets. Also telephone switches
were getting digital and needed 8 bit 'octets' to represent voice
amplitudes. So eventually everybody moved to 8 bit bytes. The main
reason, in the end, wasn't IBM but Intel. There were still many 36 bit
mainframes around, when almost all microprocessors used 8 bits. The only
exceptional chip was Intersil IM6100, which used 12 bits, but it was
really a PDP-8/E on CMOS.

Anyway, what Photoshop shows is the storage format. It uses either one
or two bytes per value. If the original source defined only 10 of the 16
bits, PS doesn't care. It processes all 16.

-- Lassi

Dear Rafe,
You might be interested in knowing about a product I love, called JPEG
Optimizer (at www.xat.com).

This program has a function that sets the compression higher for
certain parts of an image, and lower at others. If I set it at 95%,
and run this function, fields of a solid color will compress more, and
line areas, such as the edges of objects, will compress at the normal
95% I have set. I believe the term used before was "acutence." You
might want to look into it.
---
Scotty

On Fri, 20 Feb 2004 13:07:42 GMT, Raphael Bustin
wrote:

On Thu, 19 Feb 2004 23:03:26 -0800, "Lunaray"
wrote:

Thanks again for your help! Actually, my files are even bigger than I said,
I double checked and they're 565 megs each! I chose the highest bit-rate
available too, which I think was 14 bits per channel, though when I look at
the mode properties in Photoshop, "16 bits per channel" is checked, maybe
that's why they're so much bigger than the "300 meg" you quoted, ya think?


Yep, that's exactly what's happening. Scanning at 14 bits
doubles the file size.

Others have offered good advice on reducing your memory
requirements. Eg., do your high bit scans, followed by the
major color moves in Photoshop, followed finally by
conversion of your images to 8 bit mode, which will halve
their size.

Also, low-compression JPG gives a lot of bang for the buck.
Very minimal loss of image quality (I generally cannot
see it) and a very sizeable reduction in image size, usually
50-70%.


rafe b.
http://www.terrapinphoto.com