Slide scanner resolution??

"Michael Meric" wrote in message

Dear Group,

I noticed that the CS IV slide scanner does about 2900 dpi. The CS4000

does

4000 dpi. Can anyone tell me how much dpi is represented in a quality

color

magazine image or in a quality color image in a book?

Is 4000 dpi over kill for almost any "non-billboard" use, or is it a versatile resolution which is good value for money?

How does one calculate the relationship between dpi, lines, pixels, bit depth?

Quality print means about 300 dots per inch, you do the math yourself I am too tired 😉

Stephan

"Michael Meric" wrote in message

I noticed that the CS IV slide scanner does about 2900 dpi. The CS4000

does

4000 dpi. Can anyone tell me how much dpi is represented in a quality

color

magazine image or in a quality color image in a book?

Is 4000 dpi over kill for almost any "non-billboard" use, or is it a versatile resolution which is good value for money?

How does one calculate the relationship between dpi, lines, pixels, bit depth?

Forget about everything except pixels. For the highest quality prints, you need 300 pixels per inch as measured on the print. So decide on the print size in inches, multiply by 300, and you have the required size of the image in pixels. For a merely very good print, 250 pixels per inch will be quite adequate.

A Nikon Coolscan 4000 produces 4000 pixels per inch as measured on the slide. A 35mm slide is about 1.5×1 inches, so that’s about 6000×4000 pixels. Printed at 300 pixels per inch, thats 20×13.33 inches, more than adequate for an excellent 19×13 inch print assuming that the slide was taken on excellent film using an excellent lens on a solid tripod by an excellent photographer.

For good, rather than excellent, slides, a Nikon Coolscan IV at 2900 pixels per inch provides quite enough resolution. But the big difference between these two scanners is the greater dynamic range of the 4000, which provides better highlight and shadow quality. For excellent film processed by an excellent lab, you will need the 4000 to avoid blocked up shadows and washed out highlights in high contrast scenes. But for low contrast scenes or merely good film processed by an average lab, the IV should be adequate.

A good drum scan will give you 8000 pixels per inch and, more importantly, even better dynamic range, which will be needed to get the absolute best results from professional quality slides.

The batch loader for the Nikon Coolscan 4000 is very finicky about slide mounts. I have never had much luck getting it to run unattended. If you have old cardboard slide mounts, forget it. If you have plastic slide mounts, check the user’s manual to be sure they are compatible with the batch loader (none of mine are).

For scanning a lot of slides, Digital Ice^3 is an absolute necessity for removing dust and scratches. It uses an infrared channel and is so much better than Photoshop for this purpose that you should not even consider Photoshop.

If you need to salvage badly exposed or off-color slides, it is important to make exposure and color corrections using the scanner hardware. For reasonably good slides, Photoshop
will do nicely.

Warren

Thanks for a really useful posting.

I have been scanning at too high a resolution for my print size needs, and just scanning noise. Not all of us were great film developers in the past and not all labs are that great, so sometimes a lower res is probably adequate. I agree about ICE.

Bobby D

"Warren Sarle" wrote in message

"Michael Meric" wrote in message

I noticed that the CS IV slide scanner does about 2900 dpi. The CS4000

does

4000 dpi. Can anyone tell me how much dpi is represented in a quality

color

magazine image or in a quality color image in a book?

Is 4000 dpi over kill for almost any "non-billboard" use, or is it a versatile resolution which is good value for money?

How does one calculate the relationship between dpi, lines, pixels, bit depth?

Forget about everything except pixels. For the highest quality prints, you need 300 pixels per inch as measured on the print. So decide on the print size in inches, multiply by 300, and you have the required size of the image in pixels. For a merely very good print, 250 pixels per inch will be quite adequate.

A Nikon Coolscan 4000 produces 4000 pixels per inch as measured on the slide. A 35mm slide is about 1.5×1 inches, so that’s about 6000×4000 pixels. Printed at 300 pixels per inch, thats 20×13.33 inches, more than adequate for an excellent 19×13 inch print assuming that the slide was taken on excellent film using an excellent lens on a solid tripod by an excellent photographer.

For good, rather than excellent, slides, a Nikon Coolscan IV at 2900 pixels per inch provides quite enough resolution. But the big difference between these two scanners is the greater dynamic range of the 4000, which provides better highlight and shadow quality. For excellent film processed by an excellent lab, you will need the 4000 to avoid blocked up shadows and washed out highlights in high contrast scenes. But for low contrast scenes or merely good film processed by an average lab, the IV should be adequate.

A good drum scan will give you 8000 pixels per inch and, more importantly, even better dynamic range, which will be needed to get the absolute best results from professional quality slides.
The batch loader for the Nikon Coolscan 4000 is very finicky about slide mounts. I have never had much luck getting it to run unattended. If you have old cardboard slide mounts, forget it. If you have plastic slide mounts, check the user’s manual to be sure they are compatible with the batch loader (none of mine are).
For scanning a lot of slides, Digital Ice^3 is an absolute necessity for removing dust and scratches. It uses an infrared channel and is so much better than Photoshop for this purpose that you should not even consider Photoshop.

If you need to salvage badly exposed or off-color slides, it is important to make exposure and color corrections using the scanner hardware. For reasonably good slides, Photoshop
will do nicely.

On Fri, 13 Feb 2004 05:56:24 GMT, "Warren Sarle" wrote:

For good, rather than excellent, slides, a Nikon Coolscan IV at 2900 pixels per inch provides quite enough resolution. But the big difference between these two scanners is the greater dynamic range of the 4000, which provides better highlight and shadow quality. For excellent film processed by an excellent lab, you will need the 4000 to avoid blocked up shadows and washed out highlights in high contrast scenes. But for low contrast scenes or merely good film processed by an average lab, the IV should be adequate.

Except… the Coolscan IV has now been replaced by the Coolscan V (LS50) and has 4000 dpi resolution. And if you *really* want dpi then the Minolta Dimage 5400 gives you 5400 dpi.

Of course, what’s *really* important in all that is the Dmax – the Nikon gives you 4.2 and the Minolta 4.8.

Just thought I’d mention that 🙂

—

Hecate

veni, vidi, reliqui

Michael Meric wrote:

Dear Group,

I noticed that the CS IV slide scanner does about 2900 dpi. The CS4000 does 4000 dpi. Can anyone tell me how much dpi is represented in a quality color magazine image or in a quality color image in a book?

Is 4000 dpi over kill for almost any "non-billboard" use, or is it a versatile resolution which is good value for money?

How does one calculate the relationship between dpi, lines, pixels, bit depth?

Thanks much,

Michael

well 2900 dpi gives ~ 12.5 megpixel scans – about the same as the best full frame 35mm digital cameras. if you use a "full frame" for the print it really is more than enough, but if you start cropping it quickly becomes marginal! i do a lot of "action" shots, you rarely get a full frame shot, to play it safe i shoot a little wide and crop for the composition. it’s a lot easier to take away what i don’t need than add what i didn’t catch. i find less than 3000 dpi is not good enough.

as others have said a DMAX over 4 is as important as anything else. and i’d try to get it as high as possible without sacrificing any other features.