Best setting for scanning Negs

[tmc]

When scanning colour negs, I have found that scanning at low res (say 72 - 300dpi) and using a larger output size of 25x16.18 inches gives me the best results.

Scanning at 3200dpi at the original neg size, does not produce the same quality.. I get a grainy effect?

Is it better to scan at the larger size? Why is this so???????????

TMC

[LSI_Support]

You get this grainy effect because that grain is part of your image (very likely the material your image was produced onto). When you scan at a higher resolution your scanner reads more data from the scan bed. Sometimes it is data that you don't want to have - like dust or grain.

[tmc]

Hello again,


The 35mm negative is 3.36" x 2.13" (inches) @ 3200dpi = 32.6MB image in photoshop. .. But is grainy when I zoom into a persons eye in the photo.

The same 35mm Negative scanned at 25" x 16.18" @180dpi = 36.8m image in photoshop which is much clearer and not grainy when I zoom into the same eye in the photo?

This is true for all the negs I have scanned (about 30 now). Is this the best practice for neg scanning scanning when you need a >32MB image??

(you see to produce a photo for a magazine cover A4 size (300dpi), I need around a 29MB image)

Thanks
TMC

[Gregory C]

if your scanner has a maximum hardware resolution of 4000 dpi, then it can only produce 5527 x 3536 pixels for your 35mm negative (assuming your measurements of 3.36" x 2.13").

35mm negative is 3.36" x 2.13" @ 3200dpi

according to SilverFast, this calculates to 10752 x 6879 which is far more than the hardware limits of the scanner. a lot of interpolation is happening to create the final image, hence the 'grainy' effect.

35mm negative at 25" x 16.18" @ 180dpi

according to SilverFast, this calculates to 4500 x 2879 which is less than the hardware limits of the scanner. therefore, very little interpolation is happening and the image is much sharper.

if you're scanning negatives to archive, use the maximum hardware resolution of your scanner. use the resolution slider and select the second-highest resolution available on the slide. don't use the highest resolution because it is not a hardware resolution; it's an interpolated resolution which in my opinion should not be included in the slider's set of available hardware resolutions.