Getting a good scan

[Cynthia Daniel]

Here's my forumla for a good scan for the web:

1. Scan an 8x10 photo at 300 dpi. Smaller photos at a higher dpi. You want your scanner software to show a file size of around 30mb, give or take a few mb. Adjust your dpi to achieve a file of about this size. Glossy photos render a slightly better scan than matte.

2. Resize (some programs call it resampling) to the final size you want. For a web page, I use 400 pixels high so the image fits vertically within the browser screen area without vertical scrolling being necessary. The exception to this is horizontal portraits where I usually use 320 pixels high. These are not hard and fast rules, but a good rule of thumb.

3. Run unsharp mask on the image (better than sharpen), but be sure to not do so much that the image starts to "break apart" (look pixelated). Usually an image with a small face can't take as much as one with a larger face in the image.

4. Save the file and while doing this, select the file type and level of compression for .jpg files. (You'll have to select the file type of .jpg first to get this option.) For .jpg files select high quality, which will be a larger image. This is where many people go wrong by selecting a .jpg level of compression that produces an unclear, wavy or pixelated image. More and more web viewers have higher speed connections, so this is not as much of a concern as in previous days.

If you're scanning for printing:

The above dpi or higher still applies, but save the file as a tif. If you get a professonal scan in a print shop, they will likely scan at least at 600dpi, but that's more than most home computers can handle.

Be aware that tif format does not throw out any pixels and therefore is a huge file. If you're cramped for hard drive space, you can always burn these off onto a CD for later use.

If there's ever any chance you would want to do print reproduction of a painting, you might save your file as a tif and keep that as a master and create any other files, such as jpg from that one.

For the web, a good quality .jpg is what you want though, both for size considerations, plus .tif files do not display in web pages, so that's not a choice.

[Jim Riley]

My Umax scanner will scan transparencies and negatives but efforts so far have not produced sharp images and I have not found much to guide my efforts.

I would like to hear what others have learned about scanning or other services that could help me get get to editable digital files and quality prints.

Jim

[Cynthia Daniel]

Which Umax do you have? The Astra 2200? That model scans 4 x 5's fairly well, and slides seems to be very iffy.

Until I get a better scanner, I am sending most slides out to a one-hour photo place and get high-res scans put on a CD.

Probably I will end up buying a new flat-bed for photos and 4 x 5 transparencies and then a separate slide scanner. That's where my research has led to me to date.

Remember that web needs and print needs are different. Web doesn't require the quality that print does.

[Jim Riley]

Cynthia,

I have an Astra 6450 and though it scans photos adequately the slides have not been satisfactory. I returned my scanner for repair just before my last post and haven't been able to test 4" x 5" formats.

My paintings are all on slides that look pretty good but prints from those slides and scans from those prints are less then satisfactory.
Based on some of William Whitaker's comment's I am going to try shooting new work with my digital camera and print from those files.

Previously I had access to a Nikon 950 and agree with him on the quality of Nikons. I just purchased, however, a Minolta DiMage 5/ 3.3m with all the features of a single lens reflex and super controls. Prints are outstanding and I really love to be able to leave the "photo shoot" knowing that I have what I need and avoid the pain caused days later to find that what I shot was mostly useless.

Those considering a digital camera should be aware that storage media and batteries usually supplied with new cameras is not adequate and should budget for long life rechargable batteries and no less than 32 MB of storage media.

[Cynthia Daniel]

Jim,

You might want to post the digital camera part of your post in the Photography, Lighting and Techniques section of the forum. That's where most of the digital camera info is. I'm afraid it might get overlooked here in the Computer Corner.

2 tips that will result in better scans: 1. Use a photographer's Gray Scale. 2. When using the TIFF format select the LZW compression option. It makes a tremendous difference in size and information is not thrown out maintaining quality.

The gray scale is placed next to the photo and scanned. Then in Photoshop under Levels point the light dropper to the white square and the dark to the black square. This will define true black and white. Then crop out the scale and save the image.

A general rule in digital printing is to keep your file resolution between 150-300dpi at your intended output size unless you are printing Lino. Anything more will unnecesarily tie the system up with huge CPU and RAM demands. Side by side comparisons show little gain when throwing enormous amounts of resolution at a digital printer.

Printer resolution and image resolution are two different things. If your printer prints 1200x2400dpi you need only send a file with the above mentioned resolution to get a high quality print.

This is especially true with dye sublimation printers. The serve-yourself Kodak keosk printers commonly found in grocery and drug stores and your local Kinko's will produce a remarkable print from a 72dpi file.