Digital scanning and software query

[Colin Myers]

Hi,
I am considering purchasing a scanner to cover the 5" x 7" and 8" x 10" formats, both monochrome and colour and the Epson 4990 is looking a likely contender. I have followed the recent discussions on these scanners with some interest. What advantages does Silverfast Ai have over the SE software which is bundled with the scanner? Especially if you are using an advanced version of Photoshop in conjuction with it. Many of the scanner manufacturers seem to quote scan resolution in d.p.i.
Surely they scan in p.p.i.? As an almost computer illiterate, I would be most grateful for any advice the forum can offer. Many Thanks
Colin Myers

[Ted Harris]

Colin, Silverfast Ai has many advantags in terms of the adjustments it permits during scanning, especially color adjutments that simplify getting rid of color casts when scanning. For basic black and white manipulations you may do just as well with the bundled Epson or Microtek software as with SE. Bottom line, if the scaner you want comes with Ai bundled it is worth the price but if you are looking at the "consumer scanners" the difference in price between the 4990 without Ai and the V750 with it is not a good value for scanning LF film. You are better off buying the 4990 and adding Ai if you feel you need it. Having said that, I use Ai almost exclusively with my Microtek 1800f but am usually comfortable with Epson's own software when using a 4990 or 4870.

As for nomenclature, actually scanners scan in spi, or samples per inch. Monitors read/construct images in ppi or pixels per inch and printers print in dpi o rdots per inch. However, since the general public often lump all three of these different measurements together as "dpi" the manufacturers do the same in their literature. Remember too that the quoted scan resolutionnumbers you see are largely marketing hype.

[Ted Harris]

Colin, Silverfast Ai has many advantags in terms of the adjustments it permits during scanning, especially color adjutments that simplify getting rid of color casts when scanning. For basic black and white manipulations you may do just as well with the bundled Epson or Microtek software as with SE. Bottom line, if the scaner you want comes with Ai bundled it is worth the price but if you are looking at the "consumer scanners" the difference in price between the 4990 without Ai and the V750 with it is not a good value for scanning LF film. You are better off buying the 4990 and adding Ai if you feel you need it. Having said that, I use Ai almost exclusively with my Microtek 1800f but am usually comfortable with Epson's own software when using a 4990 or 4870.

As for nomenclature, actually scanners scan in spi, or samples per inch. Monitors read/construct images in ppi or pixels per inch and printers print in dpi o rdots per inch. However, since the general public often lump all three of these different measurements together as "dpi" the manufacturers do the same in their literature. Remember too that the quoted scan resolution numbers you see are largely marketing hype.

[Walter Calahan]

Silverfast AI is bundled with the Epson V750 and other useful software that you don't have to buy extra for when buying the 4990.

dpi vs. ppi. ppi is the correct terminology for anything digital. dpi is a hold over from screen printing.

I've never used the SE version of Silverfast. I use the "studio" version of AI. You get what you pay for in this world. The AI version gives more features to do more. The studio version adds even more. Go to Silverfast's web site to get the info from the horse's mouth. http://www.silverfast.com/

[Doug Fisher]

I think the added Ai features people appreciate the most are the batch scanning capabilities and the larger number of options for higher bit (48 bit) output options.

If you have another scanner already that works with Vuescan and/or Silverfast, even if it is just an old flatbed, you might want to download the free demo versions of these software packages and try out their interfaces just to make sure they suit your working style. Some people who don't try them first end up wasting their money because they find the software interface too frustrating for their working style. Each software's interface is very different.

Doug
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www.BetterScanning.com

[Colin Myers]

Ted,Walter and Doug.
Many thanks for your prompt response,advice and pointers. Your efforts have helped clear up some of my misconceptions, perhaps you can help clarify the following on a similar tack. As stated previously, I know very little about digital, but try and apply a basic commonsense approach to most things.
"Total file sizes likely to result from scanning an 8" x 10" negative or transparency".
This would appear to be a combination of scanning resolution and bit depth. Presumably, one could have a low resolution scan carried out at 24 or 48 bit depth, giving a particular file size. conversely a high resolution scan at low bit depth might generate the same file size. Is this logic fatally flawed and if not, how does one determine the optimum balance between scan resolution/bit depth. I have read in other threads that as soon as an image file is imported into Photoshop it appears to be reduced to 8bit. If this is correct, what if any are the advantages of scanning at
greater than 8 bit resolution? Surely these 24 or 48 bit scans generate absolutely huge
files which are almost impossible to manipulate.All advice gratefully received
Colin Myers

[Kirk Gittings]

Colin,

Sanning images in 48bit does create large files but it also gives you greater resources for your edits. Most PS edits destroy information in some form. If you heavily edit 8 bit files they start to get gaps in the information which shows up as white bars in your histogram and poor tonal separation in a print. 48 bit files largely avoid this.