I would need to know more about your image "zoom" application or database but here is a suggestion. The bold areas are direct responses to your question.
Think of your computer as a portal. No matter what resolution your image, it will appear on the monitor as 72dpi. Whether zoomed in to 100%, which will reveal only a part of your image on the screen, or the full image, which would be more of a "zoom" out or another sample. Back to the portal analogy. Imagine that your monitor is a 10x13 inch frame and your walking up to a 8x8 feet painting. When your away from the painting you see the full image in the frame. When you step closer you begin to select portions of the painting using the frame until your frame is touching it (100%) This is what happens with a digital image. Since your screen is 72dpi it can increase the size of a 1200x1200 pixel image to 16.5 x 16.5 inch image at 100%, but since your monitor is only 10x13 that is the only part of the image you can see. When you zoom out you will see more of the image but still at 72dpi. So, the best way to decide on securing your image would be to view the image at 100% (in your image editing application) at various levels of quality (jpeg compression). Whatever your institution can deal with, in quality of web image vs. quality of printing or repurposing on the web by others(repurposing it for use on the web is almost impossible to prevent, but you can try to track it down), will be what to base the decision on, remembering that most images are printed at the minimum 300dpi. So a 1200x1200 pixel image would be a 4x4 inch print but of very poor quality due to the jpeg compression. That is how using a "zooming" technology for images would work. This also depends on how your "zoom" functions. It may resample the detail (zoomed) image from one file (unseen by visitors but accessible to the "zoom" technology) for both the overall and detail. Someone could possibly reassemble the image by puzzling the details together (tough). What we will do here at the Indianapolis Museum Art is select detail shots of points of interest and display them along side the overall image, compressed and just large enough to be viewed full size on the monitor, the image will be no smaller than 100K. Hope this is not too much information, you may already be aware of this. However, this allows me the opportunity to get it all out. Let me know if this makes sense to you. It will be a good example for our institution if it comes across clear enough. Contact me if you have more questions. Michael Rippy Indianapolis Museum of Art 1200 W. 38th St. Indianapolis, IN. 46208 (317)923-1331ext.188 >>> [email protected] 09/25/01 12:51PM >>> Hi, My name is Karen Hudson, I am the Collection Manager at the Connecticut Historical Society. We are ready to link digital images to our database records, and we want to get a sense of what dpi other institutions are loading images at. We want to take advantage of the zooming ability our data management package has, but we don't want to load images at such a high dpi that we tempt web visitors to misuse them. I'd appreciate any feedback about what other institutions are doing. Thanks. Karen Hudson
