What size and resolution pic do I need?
January 5, 2006 6:50 AM   Subscribe

What considerations should I use in determining file format and size with a digital database that will be available online?

Specifically, I need to specify what resolution, size, etc, will be used in the Master, Access, and thumbnail file, but I hardly know exactly what those terms mean, much less what standard protocol is for these files.

I basically want small museums and individuals to have the opportunity to upload scanned images to this new website to share for classroom and research uses.
posted by stormygrey to Computers & Internet (9 answers total)
Are you writing something from scratch or are you using an existing application.
posted by bshort at 7:03 AM on January 5, 2006

There should be a question mark on the end of that sentence.
posted by bshort at 7:03 AM on January 5, 2006

Unless there's a whole world of image size rules going on that I'm completely unaware of, I'd say that the resolutions are completely at your discretion.

Use whatever fits your ideas for the site, but I would suggest to leave the master at full uploaded resolution, so in the future, you'll always have the option to revisit the resolutions and change things around.
posted by jcruden at 7:08 AM on January 5, 2006

thumbnails are usually 72dpi and small--photoshop can create them automatically.

for the regular images, i'd go 300dpi, and at least 500 pixels wide, especially if they're going to be downloaded or printed ever. Or just have that as an option, linked.

Or copy what the Met does...there's a thumbnail on this page, with links to an enlargement. (but you should bigger than they do--i'd make it so that it's at least 500-600 pixels wide) Download them and copy the specs?
posted by amberglow at 7:41 AM on January 5, 2006

Space used is a function of file format (compression) and resolution, so when deciding the size you should estimate the number of images you expect to host and match it to the ammount of storage you are willing to have. Also, if "Access" means the size or sizes available for public access, the network bandwidth available should also be taken into consideration. And time access time - 2000 X 2000 high quality images may look good, but not many people will have the patience to wait for them to render in a browser window. Anyway, the "Master" file should probably have a high quality, so you don't have problems reducing it. What it means exactly depends on what kind of images you're talking about (paintings or objects or whatever) and what kind of research they will be used in (studying the action of time in ancient Greek utensils may require very high-res images, for instance).
posted by nkyad at 7:47 AM on January 5, 2006

Thumbnail: JPG format, 72 DPI, no bigger than 200x200 pixels (or whatever you're comfortable with)

Access: Not sure what that means, medium viewable size perhaps? JPG, 72dpi, no bigger than 800x800

Master: The original image, either digital photo or a hi-res scan: 300 dpi, TIF (uncompressed or LZW compressed), any size. Big.
posted by StarForce5 at 8:32 AM on January 5, 2006

Response by poster: bshort, we will be contracting out to write a new backend database and basically everything else from scratch.
posted by stormygrey at 9:01 AM on January 5, 2006

A clarification: For images that are only displayed on screen (such as thumbnails), dpi is irrelevant. Only the overall size matters. A 200 x 200 pixel image is the same size on screen regardless of dpi setting.
posted by strangeleftydoublethink at 9:31 AM on January 5, 2006

There are lots and lots of image hosting sites out there. I'd pick a dozen and take note of what the best of them (in your judgement) do for thumbnail and image size. Some names off the top of my head flickr, fotuki, imagevenue, photobucket.

Also, it might be worth considering that average screen resultion on Windows systems is probably closer to 90DPI, not 72DPI.

Be sure to preserve the metadata provided with the uploaded image
posted by Good Brain at 9:35 AM on January 5, 2006

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