Tips for extreme file size reduction?

When I take large files from medium format film scans and shrink them to viewable jpeg or thumbnail sizes I lose a lot of the inherent image

This is taking files that might start out at say 11,000 x 8,800 pixels and reducing to 600 pixels wide for a web image or 90 pixels wide for a thumb.

I’ve tried the one step approach and also have written actions to do it in

increments and in 93% increments, which look better for most images. I’ve

tried re-scanning at 1,000 ppi instead of 4,000 ppi and this works well

but I want to avoid scanning twice at all costs.
I have two questions …

1) Anyone have any other magic numbers besides 50% and 93% for something

this? Whipping up the action is pretty trivial so I can try different

but life is too short to try all of them :).

From: "Bart van der Wolf"

I use one of 2 approaches.
1. Blur (radius depending on size reduction), and resample.

2. Filter|Pixelate|Mosaic…, single step averaging with Cell size 2=50%, 3=33.33%, 4=25%, etc., then resample with that percentage, and finish with the last bit of resizing to reach the required pixel size.

From: "Bart van der Wolf"

I use one of 2 approaches.
1. Blur (radius depending on size reduction), and resample.

Thanks Bart … I take it "blur" means Gaussian? Can you give me a

point for radius, say for one of your 5400 dpi Minolta scans?

2. Filter|Pixelate|Mosaic…, single step averaging with Cell size 2=50%, 3=33.33%, 4=25%, etc., then resample with that percentage, and finish

the last bit of resizing to reach the required pixel size.

Will try this …

When I take large files from medium format film scans and shrink them to viewable jpeg or thumbnail sizes I lose a lot of the inherent image

This is taking files that might start out at say 11,000 x 8,800 pixels and reducing to 600 pixels wide for a web image or 90 pixels wide for a thumb.
I’ve tried the one step approach and also have written actions to do it in

increments and in 93% increments, which look better for most images. I’ve

tried re-scanning at 1,000 ppi instead of 4,000 ppi and this works well

but I want to avoid scanning twice at all costs.

I have two questions …

1) Anyone have any other magic numbers besides 50% and 93% for something

this? Whipping up the action is pretty trivial so I can try different

but life is too short to try all of them :).

2) Anyone aware of a web site that has studied this in some detail in a systematic way? Got a link?

Thanks for any help.

Bill

From: "n8 skow"

Why do you scan at such hi-res if your gonna resize everything down?

From: "n8 skow"

Why do you scan at such hi-res if your gonna resize everything down?

Scanning to make large prints, I only put a few on the web so instead of "everything" it’s just a small % that need downsampling.
If my target was the web I’d probably scan at 1,000 dpi instead, but it isn’t so I don’t.

If my target was the web I’d probably scan at 1,000 dpi instead, but it

so I don’t.

Bill

In article ,
(Bill Hilton) wrote:

If my target was the web I’d probably scan at 1,000 dpi instead, but it

so I don’t.

Why 1000spi? 120 will do!

"jjs" wrote in message

In article ,
(Bill Hilton) wrote:

SNIP

If my target was the web I’d probably scan at 1,000 dpi instead, but it

isn’t

so I don’t.

Why 1000spi? 120 will do!

By scanning at a higher resolution, you can crop and resize by averaging or pixel binning. This will effectively reduce graininess, even of high speed film.