At what resolution would I have to scan a good Kodachrome 64 slide in order to put out a pro looking 16x20 print?

-- Jammer Jammer (boydoe69@dellnet.com), August 24, 2000

Answers

Depends on a host of things (your expectations in particular)

Broadly speaking you would want to print at about 300 pixels per inch.

Your image would therefore need to be:

6000 by 4800 pixels (20"x300ppi) x (16"x300ppi) pixels

This could be achieved with a raw scan at approx 4400 pixels per inch

which would suggest either the Polaroid Sprintscan 4000, or the Artix 4000 (essentially the same scanner)

Alternatively, an image scanned at a lower resolution can be interpolated to a larger resolution through something like Altamira's Genuine Fractals, which i have found to be more than satisfactory for prints up to A2 size (24"x16") - but again it depends upon your expectations.

The major problem with enlargeing to such a high ratio is not so much the scanner resolution but the quality of the transparency, even using good old photographic techiniques which are not limited by the same digital resolution, there are limitations imposed by the resolving power of lenses and film.

The ratio you are trying to achieve is a 14x enlargement, this will reveal any faults in the original (particularly a lack of focus) as well as film grain.

So even with a super scanner capable of 5000-6000 pixels per inch, don't expect miracles.

all the best

Martin Ellis

-- Martin Ellis (inca@globalnet.co.uk), August 24, 2000.

Also for those utilizing Photoshop go to http://www.ickybits.com and try out the Ultrasharpen 2 action. I believe Robert may also have it available as a plug-in now, but I use his action and on most scans it works very well. download the PDF and read it before loading and running the action. In my experience there are some saving problems (saving as jpg) associated with this action, but "save a copy" in photoshop works fine. Don't really remember what it does with a tif files, but I will try it out tomorrow and try to post findings. I really don't think it is a problem because most of my archiving is done in tif and most of my presentation (web) is in jpg. I am really looking forward to SVG (scaleable vector graphics) format which should be available in the next few months.

I guess I didn't offer much to answer your question, did I? Sorry about that! I don't know how you plan to output the file, but I would recommend a file size on the order of 150 to 200 meg. Everythin I have seen at your approximate sizing with this file size has looked good on the Lambdas and Lightjets. Looking forward to the ZBE output devices. http://www.zbe.com talk to Tony Baker tony@zbe.com The ZBE prices are much lower and the output is first quality, and these are output to RA-4 process.

-- fred (fdeaton@lycos.com), August 24, 2000.